6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
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16 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès@*
17 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
18 Copyright @copyright{} 2013 Nikita Karetnikov@*
19 Copyright @copyright{} 2014, 2015, 2016 Alex Kost@*
20 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
21 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
22 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
23 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
24 Copyright @copyright{} 2015, 2016, 2017 Ricardo Wurmus@*
25 Copyright @copyright{} 2016 Ben Woodcroft@*
26 Copyright @copyright{} 2016 Chris Marusich@*
27 Copyright @copyright{} 2016, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert@*
38 Copyright @copyright{} 2017 humanitiesNerd@*
39 Copyright @copyright{} 2017 Christopher Allan Webber@*
40 Copyright @copyright{} 2017 Marius Bakke@*
41 Copyright @copyright{} 2017 Hartmut Goebel
42 Copyright @copyright{} 2017 Maxim Cournoyer@*
44 Permission is granted to copy, distribute and/or modify this document
45 under the terms of the GNU Free Documentation License, Version 1.3 or
46 any later version published by the Free Software Foundation; with no
47 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
48 copy of the license is included in the section entitled ``GNU Free
49 Documentation License''.
52 @dircategory System administration
54 * Guix: (guix). Manage installed software and system configuration.
55 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
56 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
57 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
58 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
61 @dircategory Software development
63 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
64 * guix build: (guix)Invoking guix build. Building packages.
65 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
69 @title GNU Guix Reference Manual
70 @subtitle Using the GNU Guix Functional Package Manager
71 @author The GNU Guix Developers
74 @vskip 0pt plus 1filll
75 Edition @value{EDITION} @*
83 @c *********************************************************************
87 This document describes GNU Guix version @value{VERSION}, a functional
88 package management tool written for the GNU system.
91 * Introduction:: What is Guix about?
92 * Installation:: Installing Guix.
93 * Package Management:: Package installation, upgrade, etc.
94 * Programming Interface:: Using Guix in Scheme.
95 * Utilities:: Package management commands.
96 * GNU Distribution:: Software for your friendly GNU system.
97 * Contributing:: Your help needed!
99 * Acknowledgments:: Thanks!
100 * GNU Free Documentation License:: The license of this manual.
101 * Concept Index:: Concepts.
102 * Programming Index:: Data types, functions, and variables.
105 --- The Detailed Node Listing ---
109 * Binary Installation:: Getting Guix running in no time!
110 * Requirements:: Software needed to build and run Guix.
111 * Running the Test Suite:: Testing Guix.
112 * Setting Up the Daemon:: Preparing the build daemon's environment.
113 * Invoking guix-daemon:: Running the build daemon.
114 * Application Setup:: Application-specific setup.
116 Setting Up the Daemon
118 * Build Environment Setup:: Preparing the isolated build environment.
119 * Daemon Offload Setup:: Offloading builds to remote machines.
123 * Features:: How Guix will make your life brighter.
124 * Invoking guix package:: Package installation, removal, etc.
125 * Substitutes:: Downloading pre-built binaries.
126 * Packages with Multiple Outputs:: Single source package, multiple outputs.
127 * Invoking guix gc:: Running the garbage collector.
128 * Invoking guix pull:: Fetching the latest Guix and distribution.
129 * Invoking guix pack:: Creating software bundles.
130 * Invoking guix archive:: Exporting and importing store files.
132 Programming Interface
134 * Defining Packages:: Defining new packages.
135 * Build Systems:: Specifying how packages are built.
136 * The Store:: Manipulating the package store.
137 * Derivations:: Low-level interface to package derivations.
138 * The Store Monad:: Purely functional interface to the store.
139 * G-Expressions:: Manipulating build expressions.
143 * package Reference :: The package data type.
144 * origin Reference:: The origin data type.
148 * Invoking guix build:: Building packages from the command line.
149 * Invoking guix edit:: Editing package definitions.
150 * Invoking guix download:: Downloading a file and printing its hash.
151 * Invoking guix hash:: Computing the cryptographic hash of a file.
152 * Invoking guix import:: Importing package definitions.
153 * Invoking guix refresh:: Updating package definitions.
154 * Invoking guix lint:: Finding errors in package definitions.
155 * Invoking guix size:: Profiling disk usage.
156 * Invoking guix graph:: Visualizing the graph of packages.
157 * Invoking guix environment:: Setting up development environments.
158 * Invoking guix publish:: Sharing substitutes.
159 * Invoking guix challenge:: Challenging substitute servers.
160 * Invoking guix copy:: Copying to and from a remote store.
161 * Invoking guix container:: Process isolation.
162 * Invoking guix weather:: Assessing substitute availability.
164 Invoking @command{guix build}
166 * Common Build Options:: Build options for most commands.
167 * Package Transformation Options:: Creating variants of packages.
168 * Additional Build Options:: Options specific to 'guix build'.
169 * Debugging Build Failures:: Real life packaging experience.
173 * System Installation:: Installing the whole operating system.
174 * System Configuration:: Configuring the operating system.
175 * Documentation:: Browsing software user manuals.
176 * Installing Debugging Files:: Feeding the debugger.
177 * Security Updates:: Deploying security fixes quickly.
178 * Package Modules:: Packages from the programmer's viewpoint.
179 * Packaging Guidelines:: Growing the distribution.
180 * Bootstrapping:: GNU/Linux built from scratch.
181 * Porting:: Targeting another platform or kernel.
185 * Limitations:: What you can expect.
186 * Hardware Considerations:: Supported hardware.
187 * USB Stick Installation:: Preparing the installation medium.
188 * Preparing for Installation:: Networking, partitioning, etc.
189 * Proceeding with the Installation:: The real thing.
190 * Installing GuixSD in a VM:: GuixSD playground.
191 * Building the Installation Image:: How this comes to be.
195 * Using the Configuration System:: Customizing your GNU system.
196 * operating-system Reference:: Detail of operating-system declarations.
197 * File Systems:: Configuring file system mounts.
198 * Mapped Devices:: Block device extra processing.
199 * User Accounts:: Specifying user accounts.
200 * Locales:: Language and cultural convention settings.
201 * Services:: Specifying system services.
202 * Setuid Programs:: Programs running with root privileges.
203 * X.509 Certificates:: Authenticating HTTPS servers.
204 * Name Service Switch:: Configuring libc's name service switch.
205 * Initial RAM Disk:: Linux-Libre bootstrapping.
206 * Bootloader Configuration:: Configuring the boot loader.
207 * Invoking guix system:: Instantiating a system configuration.
208 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
209 * Defining Services:: Adding new service definitions.
213 * Base Services:: Essential system services.
214 * Scheduled Job Execution:: The mcron service.
215 * Log Rotation:: The rottlog service.
216 * Networking Services:: Network setup, SSH daemon, etc.
217 * X Window:: Graphical display.
218 * Printing Services:: Local and remote printer support.
219 * Desktop Services:: D-Bus and desktop services.
220 * Database Services:: SQL databases, key-value stores, etc.
221 * Mail Services:: IMAP, POP3, SMTP, and all that.
222 * Messaging Services:: Messaging services.
223 * Monitoring Services:: Monitoring services.
224 * Kerberos Services:: Kerberos services.
225 * Web Services:: Web servers.
226 * DNS Services:: DNS daemons.
227 * VPN Services:: VPN daemons.
228 * Network File System:: NFS related services.
229 * Continuous Integration:: The Cuirass service.
230 * Power management Services:: The TLP tool.
231 * Audio Services:: The MPD.
232 * Virtualization Services:: Virtualization services.
233 * Miscellaneous Services:: Other services.
237 * Service Composition:: The model for composing services.
238 * Service Types and Services:: Types and services.
239 * Service Reference:: API reference.
240 * Shepherd Services:: A particular type of service.
244 * Software Freedom:: What may go into the distribution.
245 * Package Naming:: What's in a name?
246 * Version Numbers:: When the name is not enough.
247 * Synopses and Descriptions:: Helping users find the right package.
248 * Python Modules:: A touch of British comedy.
249 * Perl Modules:: Little pearls.
250 * Java Packages:: Coffee break.
251 * Fonts:: Fond of fonts.
255 * Building from Git:: The latest and greatest.
256 * Running Guix Before It Is Installed:: Hacker tricks.
257 * The Perfect Setup:: The right tools.
258 * Coding Style:: Hygiene of the contributor.
259 * Submitting Patches:: Share your work.
263 * Programming Paradigm:: How to compose your elements.
264 * Modules:: Where to store your code?
265 * Data Types and Pattern Matching:: Implementing data structures.
266 * Formatting Code:: Writing conventions.
271 @c *********************************************************************
273 @chapter Introduction
276 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
277 using the international phonetic alphabet (IPA).} is a package
278 management tool for the GNU system. Guix makes it easy for unprivileged
279 users to install, upgrade, or remove packages, to roll back to a
280 previous package set, to build packages from source, and generally
281 assists with the creation and maintenance of software environments.
283 @cindex user interfaces
284 Guix provides a command-line package management interface
285 (@pxref{Invoking guix package}), a set of command-line utilities
286 (@pxref{Utilities}), as well as Scheme programming interfaces
287 (@pxref{Programming Interface}).
289 Its @dfn{build daemon} is responsible for building packages on behalf of
290 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
291 binaries from authorized sources (@pxref{Substitutes}).
293 @cindex extensibility of the distribution
294 @cindex customization, of packages
295 Guix includes package definitions for many GNU and non-GNU packages, all
296 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
297 user's computing freedom}. It is @emph{extensible}: users can write
298 their own package definitions (@pxref{Defining Packages}) and make them
299 available as independent package modules (@pxref{Package Modules}). It
300 is also @emph{customizable}: users can @emph{derive} specialized package
301 definitions from existing ones, including from the command line
302 (@pxref{Package Transformation Options}).
304 @cindex Guix System Distribution
306 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
307 where it complements the available tools without interference
308 (@pxref{Installation}), or you can use it as part of the standalone
309 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
310 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
311 system configuration and Guix takes care of instantiating the
312 configuration in a transactional, reproducible, and stateless fashion
313 (@pxref{System Configuration}).
315 @cindex functional package management
316 Under the hood, Guix implements the @dfn{functional package management}
317 discipline pioneered by Nix (@pxref{Acknowledgments}).
318 In Guix, the package build and installation process is seen
319 as a @emph{function}, in the mathematical sense. That function takes inputs,
320 such as build scripts, a compiler, and libraries, and
321 returns an installed package. As a pure function, its result depends
322 solely on its inputs---for instance, it cannot refer to software or
323 scripts that were not explicitly passed as inputs. A build function
324 always produces the same result when passed a given set of inputs. It
325 cannot alter the environment of the running system in
326 any way; for instance, it cannot create, modify, or delete files outside
327 of its build and installation directories. This is achieved by running
328 build processes in isolated environments (or @dfn{containers}), where only their
329 explicit inputs are visible.
332 The result of package build functions is @dfn{cached} in the file
333 system, in a special directory called @dfn{the store} (@pxref{The
334 Store}). Each package is installed in a directory of its own in the
335 store---by default under @file{/gnu/store}. The directory name contains
336 a hash of all the inputs used to build that package; thus, changing an
337 input yields a different directory name.
339 This approach is the foundation for the salient features of Guix: support
340 for transactional package upgrade and rollback, per-user installation, and
341 garbage collection of packages (@pxref{Features}).
344 @c *********************************************************************
346 @chapter Installation
348 @cindex installing Guix
349 GNU Guix is available for download from its website at
350 @url{http://www.gnu.org/software/guix/}. This section describes the
351 software requirements of Guix, as well as how to install it and get
354 Note that this section is concerned with the installation of the package
355 manager, which can be done on top of a running GNU/Linux system. If,
356 instead, you want to install the complete GNU operating system,
357 @pxref{System Installation}.
359 @cindex foreign distro
360 When installed on a running GNU/Linux system---thereafter called a
361 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
362 without interference. Its data lives exclusively in two directories,
363 usually @file{/gnu/store} and @file{/var/guix}; other files on your
364 system, such as @file{/etc}, are left untouched.
366 Once installed, Guix can be updated by running @command{guix pull}
367 (@pxref{Invoking guix pull}).
370 * Binary Installation:: Getting Guix running in no time!
371 * Requirements:: Software needed to build and run Guix.
372 * Running the Test Suite:: Testing Guix.
373 * Setting Up the Daemon:: Preparing the build daemon's environment.
374 * Invoking guix-daemon:: Running the build daemon.
375 * Application Setup:: Application-specific setup.
378 @node Binary Installation
379 @section Binary Installation
381 @cindex installing Guix from binaries
382 This section describes how to install Guix on an arbitrary system from a
383 self-contained tarball providing binaries for Guix and for all its
384 dependencies. This is often quicker than installing from source, which
385 is described in the next sections. The only requirement is to have
388 Installing goes along these lines:
392 @cindex downloading Guix binary
393 Download the binary tarball from
394 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
395 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
396 already running the kernel Linux, and so on.
398 @c The following is somewhat duplicated in ``System Installation''.
399 Make sure to download the associated @file{.sig} file and to verify the
400 authenticity of the tarball against it, along these lines:
403 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
404 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
407 If that command fails because you do not have the required public key,
408 then run this command to import it:
411 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
415 and rerun the @code{gpg --verify} command.
416 @c end authentication part
423 # tar --warning=no-timestamp -xf \
424 guix-binary-@value{VERSION}.@var{system}.tar.xz
425 # mv var/guix /var/ && mv gnu /
428 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
429 The latter contains a ready-to-use profile for @code{root} (see next
432 Do @emph{not} unpack the tarball on a working Guix system since that
433 would overwrite its own essential files.
435 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
436 not emit warnings about ``implausibly old time stamps'' (such
437 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
439 They stem from the fact that all the
440 files in the archive have their modification time set to zero (which
441 means January 1st, 1970.) This is done on purpose to make sure the
442 archive content is independent of its creation time, thus making it
446 Make @code{root}'s profile available under @file{~/.guix-profile}:
449 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
453 Source @file{etc/profile} to augment @code{PATH} and other relevant
454 environment variables:
457 # GUIX_PROFILE=$HOME/.guix-profile \
458 source $GUIX_PROFILE/etc/profile
462 Create the group and user accounts for build users as explained below
463 (@pxref{Build Environment Setup}).
466 Run the daemon, and set it to automatically start on boot.
468 If your host distro uses the systemd init system, this can be achieved
471 @c Versions of systemd that supported symlinked service files are not
472 @c yet widely deployed, so we should suggest that users copy the service
475 @c See this thread for more information:
476 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
479 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
481 # systemctl start guix-daemon && systemctl enable guix-daemon
484 If your host distro uses the Upstart init system:
487 # initctl reload-configuration
488 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
492 Otherwise, you can still start the daemon manually with:
495 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
499 Make the @command{guix} command available to other users on the machine,
503 # mkdir -p /usr/local/bin
505 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
508 It is also a good idea to make the Info version of this manual available
512 # mkdir -p /usr/local/share/info
513 # cd /usr/local/share/info
514 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
518 That way, assuming @file{/usr/local/share/info} is in the search path,
519 running @command{info guix} will open this manual (@pxref{Other Info
520 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
524 @cindex substitutes, authorization thereof
525 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
526 (@pxref{Substitutes}), authorize them:
529 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
533 Each user may need to perform a few additional steps to make their Guix
534 environment ready for use, @pxref{Application Setup}.
537 Voilà, the installation is complete!
539 You can confirm that Guix is working by installing a sample package into
543 # guix package -i hello
546 The @code{guix} package must remain available in @code{root}'s profile,
547 or it would become subject to garbage collection---in which case you
548 would find yourself badly handicapped by the lack of the @command{guix}
549 command. In other words, do not remove @code{guix} by running
550 @code{guix package -r guix}.
552 The binary installation tarball can be (re)produced and verified simply
553 by running the following command in the Guix source tree:
556 make guix-binary.@var{system}.tar.xz
560 ... which, in turn, runs:
563 guix pack -s @var{system} --localstatedir guix
566 @xref{Invoking guix pack}, for more info on this handy tool.
569 @section Requirements
571 This section lists requirements when building Guix from source. The
572 build procedure for Guix is the same as for other GNU software, and is
573 not covered here. Please see the files @file{README} and @file{INSTALL}
574 in the Guix source tree for additional details.
576 GNU Guix depends on the following packages:
579 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
580 later, including 2.2.x;
581 @item @url{http://gnupg.org/, GNU libgcrypt};
583 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
584 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
585 Guile,, gnutls-guile, GnuTLS-Guile});
587 @c FIXME: Specify a version number once a release has been made.
588 @uref{https://gitlab.com/guile-git/guile-git, Guile-Git}, from August
590 @item @url{http://www.gnu.org/software/make/, GNU Make}.
593 The following dependencies are optional:
598 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
599 allow you to use the @command{guix import pypi} command (@pxref{Invoking
600 guix import}). It is of
601 interest primarily for developers and not for casual users.
604 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
605 Support for build offloading (@pxref{Daemon Offload Setup}) and
606 @command{guix copy} (@pxref{Invoking guix copy}) depends on
607 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
608 version 0.10.2 or later.
611 When @url{http://zlib.net, zlib} is available, @command{guix publish}
612 can compress build byproducts (@pxref{Invoking guix publish}).
615 Unless @code{--disable-daemon} was passed to @command{configure}, the
616 following packages are also needed:
619 @item @url{http://sqlite.org, SQLite 3};
620 @item @url{http://www.bzip.org, libbz2};
621 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
625 @cindex state directory
626 When configuring Guix on a system that already has a Guix installation,
627 be sure to specify the same state directory as the existing installation
628 using the @code{--localstatedir} option of the @command{configure}
629 script (@pxref{Directory Variables, @code{localstatedir},, standards,
630 GNU Coding Standards}). The @command{configure} script protects against
631 unintended misconfiguration of @var{localstatedir} so you do not
632 inadvertently corrupt your store (@pxref{The Store}).
634 @cindex Nix, compatibility
635 When a working installation of @url{http://nixos.org/nix/, the Nix package
636 manager} is available, you
637 can instead configure Guix with @code{--disable-daemon}. In that case,
638 Nix replaces the three dependencies above.
640 Guix is compatible with Nix, so it is possible to share the same store
641 between both. To do so, you must pass @command{configure} not only the
642 same @code{--with-store-dir} value, but also the same
643 @code{--localstatedir} value. The latter is essential because it
644 specifies where the database that stores metadata about the store is
645 located, among other things. The default values for Nix are
646 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
647 Note that @code{--disable-daemon} is not required if
648 your goal is to share the store with Nix.
650 @node Running the Test Suite
651 @section Running the Test Suite
654 After a successful @command{configure} and @code{make} run, it is a good
655 idea to run the test suite. It can help catch issues with the setup or
656 environment, or bugs in Guix itself---and really, reporting test
657 failures is a good way to help improve the software. To run the test
664 Test cases can run in parallel: you can use the @code{-j} option of
665 GNU@tie{}make to speed things up. The first run may take a few minutes
666 on a recent machine; subsequent runs will be faster because the store
667 that is created for test purposes will already have various things in
670 It is also possible to run a subset of the tests by defining the
671 @code{TESTS} makefile variable as in this example:
674 make check TESTS="tests/store.scm tests/cpio.scm"
677 By default, tests results are displayed at a file level. In order to
678 see the details of every individual test cases, it is possible to define
679 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
682 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
685 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
686 @file{test-suite.log} file. Please specify the Guix version being used
687 as well as version numbers of the dependencies (@pxref{Requirements}) in
690 Guix also comes with a whole-system test suite that tests complete
691 GuixSD operating system instances. It can only run on systems where
692 Guix is already installed, using:
699 or, again, by defining @code{TESTS} to select a subset of tests to run:
702 make check-system TESTS="basic mcron"
705 These system tests are defined in the @code{(gnu tests @dots{})}
706 modules. They work by running the operating systems under test with
707 lightweight instrumentation in a virtual machine (VM). They can be
708 computationally intensive or rather cheap, depending on whether
709 substitutes are available for their dependencies (@pxref{Substitutes}).
710 Some of them require a lot of storage space to hold VM images.
712 Again in case of test failures, please send @email{bug-guix@@gnu.org}
715 @node Setting Up the Daemon
716 @section Setting Up the Daemon
719 Operations such as building a package or running the garbage collector
720 are all performed by a specialized process, the @dfn{build daemon}, on
721 behalf of clients. Only the daemon may access the store and its
722 associated database. Thus, any operation that manipulates the store
723 goes through the daemon. For instance, command-line tools such as
724 @command{guix package} and @command{guix build} communicate with the
725 daemon (@i{via} remote procedure calls) to instruct it what to do.
727 The following sections explain how to prepare the build daemon's
728 environment. See also @ref{Substitutes}, for information on how to allow
729 the daemon to download pre-built binaries.
732 * Build Environment Setup:: Preparing the isolated build environment.
733 * Daemon Offload Setup:: Offloading builds to remote machines.
736 @node Build Environment Setup
737 @subsection Build Environment Setup
739 @cindex build environment
740 In a standard multi-user setup, Guix and its daemon---the
741 @command{guix-daemon} program---are installed by the system
742 administrator; @file{/gnu/store} is owned by @code{root} and
743 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
744 Guix tools to build packages or otherwise access the store, and the
745 daemon will do it on their behalf, ensuring that the store is kept in a
746 consistent state, and allowing built packages to be shared among users.
749 When @command{guix-daemon} runs as @code{root}, you may not want package
750 build processes themselves to run as @code{root} too, for obvious
751 security reasons. To avoid that, a special pool of @dfn{build users}
752 should be created for use by build processes started by the daemon.
753 These build users need not have a shell and a home directory: they will
754 just be used when the daemon drops @code{root} privileges in build
755 processes. Having several such users allows the daemon to launch
756 distinct build processes under separate UIDs, which guarantees that they
757 do not interfere with each other---an essential feature since builds are
758 regarded as pure functions (@pxref{Introduction}).
760 On a GNU/Linux system, a build user pool may be created like this (using
761 Bash syntax and the @code{shadow} commands):
763 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
764 @c for why `-G' is needed.
766 # groupadd --system guixbuild
767 # for i in `seq -w 1 10`;
769 useradd -g guixbuild -G guixbuild \
770 -d /var/empty -s `which nologin` \
771 -c "Guix build user $i" --system \
777 The number of build users determines how many build jobs may run in
778 parallel, as specified by the @option{--max-jobs} option
779 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
780 @command{guix system vm} and related commands, you may need to add the
781 build users to the @code{kvm} group so they can access @file{/dev/kvm},
782 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
783 (@pxref{Invoking guix system}).
785 The @code{guix-daemon} program may then be run as @code{root} with the
786 following command@footnote{If your machine uses the systemd init system,
787 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
788 file in @file{/etc/systemd/system} will ensure that
789 @command{guix-daemon} is automatically started. Similarly, if your
790 machine uses the Upstart init system, drop the
791 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
792 file in @file{/etc/init}.}:
795 # guix-daemon --build-users-group=guixbuild
800 This way, the daemon starts build processes in a chroot, under one of
801 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
802 environment contains nothing but:
804 @c Keep this list in sync with libstore/build.cc! -----------------------
807 a minimal @code{/dev} directory, created mostly independently from the
808 host @code{/dev}@footnote{``Mostly'', because while the set of files
809 that appear in the chroot's @code{/dev} is fixed, most of these files
810 can only be created if the host has them.};
813 the @code{/proc} directory; it only shows the processes of the container
814 since a separate PID name space is used;
817 @file{/etc/passwd} with an entry for the current user and an entry for
821 @file{/etc/group} with an entry for the user's group;
824 @file{/etc/hosts} with an entry that maps @code{localhost} to
828 a writable @file{/tmp} directory.
831 You can influence the directory where the daemon stores build trees
832 @i{via} the @code{TMPDIR} environment variable. However, the build tree
833 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
834 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
835 This way, the value of @code{TMPDIR} does not leak inside build
836 environments, which avoids discrepancies in cases where build processes
837 capture the name of their build tree.
840 The daemon also honors the @code{http_proxy} environment variable for
841 HTTP downloads it performs, be it for fixed-output derivations
842 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
844 If you are installing Guix as an unprivileged user, it is still possible
845 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
846 However, build processes will not be isolated from one another, and not
847 from the rest of the system. Thus, build processes may interfere with
848 each other, and may access programs, libraries, and other files
849 available on the system---making it much harder to view them as
850 @emph{pure} functions.
853 @node Daemon Offload Setup
854 @subsection Using the Offload Facility
858 When desired, the build daemon can @dfn{offload} derivation builds to
859 other machines running Guix, using the @code{offload} @dfn{build
860 hook}@footnote{This feature is available only when
861 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
863 feature is enabled, a list of user-specified build machines is read from
864 @file{/etc/guix/machines.scm}; every time a build is requested, for
865 instance via @code{guix build}, the daemon attempts to offload it to one
866 of the machines that satisfy the constraints of the derivation, in
867 particular its system type---e.g., @file{x86_64-linux}. Missing
868 prerequisites for the build are copied over SSH to the target machine,
869 which then proceeds with the build; upon success the output(s) of the
870 build are copied back to the initial machine.
872 The @file{/etc/guix/machines.scm} file typically looks like this:
876 (name "eightysix.example.org")
877 (system "x86_64-linux")
878 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
880 (speed 2.)) ;incredibly fast!
883 (name "meeps.example.org")
884 (system "mips64el-linux")
885 (host-key "ssh-rsa AAAAB3Nza@dots{}")
888 (string-append (getenv "HOME")
889 "/.ssh/identity-for-guix"))))
893 In the example above we specify a list of two build machines, one for
894 the @code{x86_64} architecture and one for the @code{mips64el}
897 In fact, this file is---not surprisingly!---a Scheme file that is
898 evaluated when the @code{offload} hook is started. Its return value
899 must be a list of @code{build-machine} objects. While this example
900 shows a fixed list of build machines, one could imagine, say, using
901 DNS-SD to return a list of potential build machines discovered in the
902 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
903 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
906 @deftp {Data Type} build-machine
907 This data type represents build machines to which the daemon may offload
908 builds. The important fields are:
913 The host name of the remote machine.
916 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
919 The user account to use when connecting to the remote machine over SSH.
920 Note that the SSH key pair must @emph{not} be passphrase-protected, to
921 allow non-interactive logins.
924 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
925 This is used to authenticate the machine when we connect to it. It is a
926 long string that looks like this:
929 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
932 If the machine is running the OpenSSH daemon, @command{sshd}, the host
933 key can be found in a file such as
934 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
936 If the machine is running the SSH daemon of GNU@tie{}lsh,
937 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
938 similar file. It can be converted to the OpenSSH format using
939 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
942 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
943 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
948 A number of optional fields may be specified:
952 @item @code{port} (default: @code{22})
953 Port number of SSH server on the machine.
955 @item @code{private-key} (default: @file{~root/.ssh/id_rsa})
956 The SSH private key file to use when connecting to the machine, in
959 Note that the default value is the private key @emph{of the root
960 account}. Make sure it exists if you use the default.
962 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
963 @itemx @code{compression-level} (default: @code{3})
964 The SSH-level compression methods and compression level requested.
966 Note that offloading relies on SSH compression to reduce bandwidth usage
967 when transferring files to and from build machines.
969 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
970 File name of the Unix-domain socket @command{guix-daemon} is listening
973 @item @code{parallel-builds} (default: @code{1})
974 The number of builds that may run in parallel on the machine.
976 @item @code{speed} (default: @code{1.0})
977 A ``relative speed factor''. The offload scheduler will tend to prefer
978 machines with a higher speed factor.
980 @item @code{features} (default: @code{'()})
981 A list of strings denoting specific features supported by the machine.
982 An example is @code{"kvm"} for machines that have the KVM Linux modules
983 and corresponding hardware support. Derivations can request features by
984 name, and they will be scheduled on matching build machines.
989 The @code{guile} command must be in the search path on the build
990 machines. In addition, the Guix modules must be in
991 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
992 this is the case by running:
995 ssh build-machine guile -c "'(use-modules (guix config))'"
998 There is one last thing to do once @file{machines.scm} is in place. As
999 explained above, when offloading, files are transferred back and forth
1000 between the machine stores. For this to work, you first need to
1001 generate a key pair on each machine to allow the daemon to export signed
1002 archives of files from the store (@pxref{Invoking guix archive}):
1005 # guix archive --generate-key
1009 Each build machine must authorize the key of the master machine so that
1010 it accepts store items it receives from the master:
1013 # guix archive --authorize < master-public-key.txt
1017 Likewise, the master machine must authorize the key of each build machine.
1019 All the fuss with keys is here to express pairwise mutual trust
1020 relations between the master and the build machines. Concretely, when
1021 the master receives files from a build machine (and @i{vice versa}), its
1022 build daemon can make sure they are genuine, have not been tampered
1023 with, and that they are signed by an authorized key.
1025 @cindex offload test
1026 To test whether your setup is operational, run this command on the
1033 This will attempt to connect to each of the build machines specified in
1034 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1035 available on each machine, attempt to export to the machine and import
1036 from it, and report any error in the process.
1038 If you want to test a different machine file, just specify it on the
1042 # guix offload test machines-qualif.scm
1045 Last, you can test the subset of the machines whose name matches a
1046 regular expression like this:
1049 # guix offload test machines.scm '\.gnu\.org$'
1052 @node Invoking guix-daemon
1053 @section Invoking @command{guix-daemon}
1055 The @command{guix-daemon} program implements all the functionality to
1056 access the store. This includes launching build processes, running the
1057 garbage collector, querying the availability of a build result, etc. It
1058 is normally run as @code{root} like this:
1061 # guix-daemon --build-users-group=guixbuild
1065 For details on how to set it up, @pxref{Setting Up the Daemon}.
1068 @cindex container, build environment
1069 @cindex build environment
1070 @cindex reproducible builds
1071 By default, @command{guix-daemon} launches build processes under
1072 different UIDs, taken from the build group specified with
1073 @code{--build-users-group}. In addition, each build process is run in a
1074 chroot environment that only contains the subset of the store that the
1075 build process depends on, as specified by its derivation
1076 (@pxref{Programming Interface, derivation}), plus a set of specific
1077 system directories. By default, the latter contains @file{/dev} and
1078 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1079 @dfn{container}: in addition to having its own file system tree, it has
1080 a separate mount name space, its own PID name space, network name space,
1081 etc. This helps achieve reproducible builds (@pxref{Features}).
1083 When the daemon performs a build on behalf of the user, it creates a
1084 build directory under @file{/tmp} or under the directory specified by
1085 its @code{TMPDIR} environment variable; this directory is shared with
1086 the container for the duration of the build. Be aware that using a
1087 directory other than @file{/tmp} can affect build results---for example,
1088 with a longer directory name, a build process that uses Unix-domain
1089 sockets might hit the name length limitation for @code{sun_path}, which
1090 it would otherwise not hit.
1092 The build directory is automatically deleted upon completion, unless the
1093 build failed and the client specified @option{--keep-failed}
1094 (@pxref{Invoking guix build, @option{--keep-failed}}).
1096 The following command-line options are supported:
1099 @item --build-users-group=@var{group}
1100 Take users from @var{group} to run build processes (@pxref{Setting Up
1101 the Daemon, build users}).
1103 @item --no-substitutes
1105 Do not use substitutes for build products. That is, always build things
1106 locally instead of allowing downloads of pre-built binaries
1107 (@pxref{Substitutes}).
1109 By default substitutes are used, unless the client---such as the
1110 @command{guix package} command---is explicitly invoked with
1111 @code{--no-substitutes}.
1113 When the daemon runs with @code{--no-substitutes}, clients can still
1114 explicitly enable substitution @i{via} the @code{set-build-options}
1115 remote procedure call (@pxref{The Store}).
1117 @item --substitute-urls=@var{urls}
1118 @anchor{daemon-substitute-urls}
1119 Consider @var{urls} the default whitespace-separated list of substitute
1120 source URLs. When this option is omitted,
1121 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1122 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1124 This means that substitutes may be downloaded from @var{urls}, as long
1125 as they are signed by a trusted signature (@pxref{Substitutes}).
1128 @item --no-build-hook
1129 Do not use the @dfn{build hook}.
1131 The build hook is a helper program that the daemon can start and to
1132 which it submits build requests. This mechanism is used to offload
1133 builds to other machines (@pxref{Daemon Offload Setup}).
1135 @item --cache-failures
1136 Cache build failures. By default, only successful builds are cached.
1138 When this option is used, @command{guix gc --list-failures} can be used
1139 to query the set of store items marked as failed; @command{guix gc
1140 --clear-failures} removes store items from the set of cached failures.
1141 @xref{Invoking guix gc}.
1143 @item --cores=@var{n}
1145 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1148 The default value is @code{0}, but it may be overridden by clients, such
1149 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1152 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1153 in the build process, which can then use it to exploit internal
1154 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1156 @item --max-jobs=@var{n}
1158 Allow at most @var{n} build jobs in parallel. The default value is
1159 @code{1}. Setting it to @code{0} means that no builds will be performed
1160 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1161 Setup}), or simply fail.
1163 @item --max-silent-time=@var{seconds}
1164 When the build or substitution process remains silent for more than
1165 @var{seconds}, terminate it and report a build failure.
1167 The default value is @code{0}, which disables the timeout.
1169 The value specified here can be overridden by clients (@pxref{Common
1170 Build Options, @code{--max-silent-time}}).
1172 @item --timeout=@var{seconds}
1173 Likewise, when the build or substitution process lasts for more than
1174 @var{seconds}, terminate it and report a build failure.
1176 The default value is @code{0}, which disables the timeout.
1178 The value specified here can be overridden by clients (@pxref{Common
1179 Build Options, @code{--timeout}}).
1181 @item --rounds=@var{N}
1182 Build each derivation @var{n} times in a row, and raise an error if
1183 consecutive build results are not bit-for-bit identical. Note that this
1184 setting can be overridden by clients such as @command{guix build}
1185 (@pxref{Invoking guix build}).
1187 When used in conjunction with @option{--keep-failed}, the differing
1188 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1189 This makes it easy to look for differences between the two results.
1192 Produce debugging output.
1194 This is useful to debug daemon start-up issues, but then it may be
1195 overridden by clients, for example the @code{--verbosity} option of
1196 @command{guix build} (@pxref{Invoking guix build}).
1198 @item --chroot-directory=@var{dir}
1199 Add @var{dir} to the build chroot.
1201 Doing this may change the result of build processes---for instance if
1202 they use optional dependencies found in @var{dir} when it is available,
1203 and not otherwise. For that reason, it is not recommended to do so.
1204 Instead, make sure that each derivation declares all the inputs that it
1207 @item --disable-chroot
1208 Disable chroot builds.
1210 Using this option is not recommended since, again, it would allow build
1211 processes to gain access to undeclared dependencies. It is necessary,
1212 though, when @command{guix-daemon} is running under an unprivileged user
1215 @item --disable-log-compression
1216 Disable compression of the build logs.
1218 Unless @code{--lose-logs} is used, all the build logs are kept in the
1219 @var{localstatedir}. To save space, the daemon automatically compresses
1220 them with bzip2 by default. This option disables that.
1222 @item --disable-deduplication
1223 @cindex deduplication
1224 Disable automatic file ``deduplication'' in the store.
1226 By default, files added to the store are automatically ``deduplicated'':
1227 if a newly added file is identical to another one found in the store,
1228 the daemon makes the new file a hard link to the other file. This can
1229 noticeably reduce disk usage, at the expense of slightly increased
1230 input/output load at the end of a build process. This option disables
1233 @item --gc-keep-outputs[=yes|no]
1234 Tell whether the garbage collector (GC) must keep outputs of live
1237 When set to ``yes'', the GC will keep the outputs of any live derivation
1238 available in the store---the @code{.drv} files. The default is ``no'',
1239 meaning that derivation outputs are kept only if they are GC roots.
1241 @item --gc-keep-derivations[=yes|no]
1242 Tell whether the garbage collector (GC) must keep derivations
1243 corresponding to live outputs.
1245 When set to ``yes'', as is the case by default, the GC keeps
1246 derivations---i.e., @code{.drv} files---as long as at least one of their
1247 outputs is live. This allows users to keep track of the origins of
1248 items in their store. Setting it to ``no'' saves a bit of disk space.
1250 Note that when both @code{--gc-keep-derivations} and
1251 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1252 prerequisites (the sources, compiler, libraries, and other build-time
1253 tools) of live objects in the store, regardless of whether these
1254 prerequisites are live. This is convenient for developers since it
1255 saves rebuilds or downloads.
1257 @item --impersonate-linux-2.6
1258 On Linux-based systems, impersonate Linux 2.6. This means that the
1259 kernel's @code{uname} system call will report 2.6 as the release number.
1261 This might be helpful to build programs that (usually wrongfully) depend
1262 on the kernel version number.
1265 Do not keep build logs. By default they are kept under
1266 @code{@var{localstatedir}/guix/log}.
1268 @item --system=@var{system}
1269 Assume @var{system} as the current system type. By default it is the
1270 architecture/kernel pair found at configure time, such as
1271 @code{x86_64-linux}.
1273 @item --listen=@var{endpoint}
1274 Listen for connections on @var{endpoint}. @var{endpoint} is interpreted
1275 as the file name of a Unix-domain socket if it starts with
1276 @code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a
1277 host name or host name and port to listen to. Here are a few examples:
1280 @item --listen=/gnu/var/daemon
1281 Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket,
1282 creating it if needed.
1284 @item --listen=localhost
1285 @cindex daemon, remote access
1286 @cindex remote access to the daemon
1287 @cindex daemon, cluster setup
1288 @cindex clusters, daemon setup
1289 Listen for TCP connections on the network interface corresponding to
1290 @code{localhost}, on port 44146.
1292 @item --listen=128.0.0.42:1234
1293 Listen for TCP connections on the network interface corresponding to
1294 @code{128.0.0.42}, on port 1234.
1297 This option can be repeated multiple times, in which case
1298 @command{guix-daemon} accepts connections on all the specified
1299 endpoints. Users can tell client commands what endpoint to connect to
1300 by setting the @code{GUIX_DAEMON_SOCKET} environment variable
1301 (@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}).
1304 The daemon protocol is @emph{unauthenticated and unencrypted}. Using
1305 @code{--listen=@var{host}} is suitable on local networks, such as
1306 clusters, where only trusted nodes may connect to the build daemon. In
1307 other cases where remote access to the daemon is needed, we recommend
1308 using Unix-domain sockets along with SSH.
1311 When @code{--listen} is omitted, @command{guix-daemon} listens for
1312 connections on the Unix-domain socket located at
1313 @file{@var{localstatedir}/daemon-socket/socket}.
1317 @node Application Setup
1318 @section Application Setup
1320 @cindex foreign distro
1321 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1322 so-called @dfn{foreign distro}---a few additional steps are needed to
1323 get everything in place. Here are some of them.
1327 @anchor{locales-and-locpath}
1328 @cindex locales, when not on GuixSD
1330 @vindex GUIX_LOCPATH
1331 Packages installed @i{via} Guix will not use the locale data of the
1332 host system. Instead, you must first install one of the locale packages
1333 available with Guix and then define the @code{GUIX_LOCPATH} environment
1337 $ guix package -i glibc-locales
1338 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1341 Note that the @code{glibc-locales} package contains data for all the
1342 locales supported by the GNU@tie{}libc and weighs in at around
1343 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1344 limited to a few UTF-8 locales.
1346 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1347 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1348 Manual}). There are two important differences though:
1352 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1353 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1354 to make sure the programs of the foreign distro will not end up loading
1355 incompatible locale data.
1358 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1359 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1360 should your Guix profile contain a mixture of programs linked against
1361 different libc version, each libc version will only try to load locale
1362 data in the right format.
1365 This is important because the locale data format used by different libc
1366 versions may be incompatible.
1368 @subsection Name Service Switch
1370 @cindex name service switch, glibc
1371 @cindex NSS (name service switch), glibc
1372 @cindex nscd (name service caching daemon)
1373 @cindex name service caching daemon (nscd)
1374 When using Guix on a foreign distro, we @emph{strongly recommend} that
1375 the system run the GNU C library's @dfn{name service cache daemon},
1376 @command{nscd}, which should be listening on the
1377 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1378 installed with Guix may fail to look up host names or user accounts, or
1379 may even crash. The next paragraphs explain why.
1381 @cindex @file{nsswitch.conf}
1382 The GNU C library implements a @dfn{name service switch} (NSS), which is
1383 an extensible mechanism for ``name lookups'' in general: host name
1384 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1385 The GNU C Library Reference Manual}).
1387 @cindex Network information service (NIS)
1388 @cindex NIS (Network information service)
1389 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1390 lookup implementations: for example, the @code{nss-mdns} plugin allow
1391 resolution of @code{.local} host names, the @code{nis} plugin allows
1392 user account lookup using the Network information service (NIS), and so
1393 on. These extra ``lookup services'' are configured system-wide in
1394 @file{/etc/nsswitch.conf}, and all the programs running on the system
1395 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1398 When they perform a name lookup---for instance by calling the
1399 @code{getaddrinfo} function in C---applications first try to connect to
1400 the nscd; on success, nscd performs name lookups on their behalf. If
1401 the nscd is not running, then they perform the name lookup by
1402 themselves, by loading the name lookup services into their own address
1403 space and running it. These name lookup services---the
1404 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1405 the host system's C library, rather than from the C library the
1406 application is linked against (the C library coming from Guix).
1408 And this is where the problem is: if your application is linked against
1409 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1410 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1411 likely crash or have its name lookups fail unexpectedly.
1413 Running @command{nscd} on the system, among other advantages, eliminates
1414 this binary incompatibility problem because those @code{libnss_*.so}
1415 files are loaded in the @command{nscd} process, not in applications
1418 @subsection X11 Fonts
1421 The majority of graphical applications use Fontconfig to locate and
1422 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1423 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1424 by default. Thus, to allow graphical applications installed with Guix
1425 to display fonts, you have to install fonts with Guix as well.
1426 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1427 @code{font-gnu-freefont-ttf}.
1429 To display text written in Chinese languages, Japanese, or Korean in
1430 graphical applications, consider installing
1431 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1432 has multiple outputs, one per language family (@pxref{Packages with
1433 Multiple Outputs}). For instance, the following command installs fonts
1434 for Chinese languages:
1437 guix package -i font-adobe-source-han-sans:cn
1440 @cindex @code{xterm}
1441 Older programs such as @command{xterm} do not use Fontconfig and instead
1442 rely on server-side font rendering. Such programs require to specify a
1443 full name of a font using XLFD (X Logical Font Description), like this:
1446 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1449 To be able to use such full names for the TrueType fonts installed in
1450 your Guix profile, you need to extend the font path of the X server:
1453 xset +fp ~/.guix-profile/share/fonts/truetype
1456 @cindex @code{xlsfonts}
1457 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1458 to make sure your TrueType fonts are listed there.
1460 @cindex @code{fc-cache}
1462 After installing fonts you may have to refresh the font cache to use
1463 them in applications. The same applies when applications installed via
1464 Guix do not seem to find fonts. To force rebuilding of the font cache
1465 run @code{fc-cache -f}. The @code{fc-cache} command is provided by the
1466 @code{fontconfig} package.
1468 @subsection X.509 Certificates
1470 @cindex @code{nss-certs}
1471 The @code{nss-certs} package provides X.509 certificates, which allow
1472 programs to authenticate Web servers accessed over HTTPS.
1474 When using Guix on a foreign distro, you can install this package and
1475 define the relevant environment variables so that packages know where to
1476 look for certificates. @xref{X.509 Certificates}, for detailed
1479 @subsection Emacs Packages
1481 @cindex @code{emacs}
1482 When you install Emacs packages with Guix, the elisp files may be placed
1483 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1485 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1486 directory exists because potentially there may exist thousands of Emacs
1487 packages and storing all their files in a single directory may be not
1488 reliable (because of name conflicts). So we think using a separate
1489 directory for each package is a good idea. It is very similar to how
1490 the Emacs package system organizes the file structure (@pxref{Package
1491 Files,,, emacs, The GNU Emacs Manual}).
1493 By default, Emacs (installed with Guix) ``knows'' where these packages
1494 are placed, so you do not need to perform any configuration. If, for
1495 some reason, you want to avoid auto-loading Emacs packages installed
1496 with Guix, you can do so by running Emacs with @code{--no-site-file}
1497 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1499 @subsection The GCC toolchain
1504 Guix offers individual compiler packages such as @code{gcc} but if you
1505 are in need of a complete toolchain for compiling and linking source
1506 code what you really want is the @code{gcc-toolchain} package. This
1507 package provides a complete GCC toolchain for C/C++ development,
1508 including GCC itself, the GNU C Library (headers and binaries, plus
1509 debugging symbols in the @code{debug} output), Binutils, and a linker
1512 @cindex attempt to use impure library, error message
1514 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1515 passed to the linker, add corresponding @code{-rpath} arguments, and
1516 invoke the actual linker with this new set of arguments. By default,
1517 the linker wrapper refuses to link to libraries outside the store to
1518 ensure ``purity''. This can be annoying when using the toolchain to
1519 link with local libraries. To allow references to libraries outside the
1520 store you need to define the environment variable
1521 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1525 @c *********************************************************************
1526 @node Package Management
1527 @chapter Package Management
1530 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1531 remove software packages, without having to know about their build
1532 procedures or dependencies. Guix also goes beyond this obvious set of
1535 This chapter describes the main features of Guix, as well as the
1536 package management tools it provides. Along with the command-line
1537 interface described below (@pxref{Invoking guix package, @code{guix
1538 package}}), you may also use Emacs Interface (@pxref{Top,,,
1539 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1540 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1544 guix package -i emacs-guix
1548 * Features:: How Guix will make your life brighter.
1549 * Invoking guix package:: Package installation, removal, etc.
1550 * Substitutes:: Downloading pre-built binaries.
1551 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1552 * Invoking guix gc:: Running the garbage collector.
1553 * Invoking guix pull:: Fetching the latest Guix and distribution.
1554 * Invoking guix pack:: Creating software bundles.
1555 * Invoking guix archive:: Exporting and importing store files.
1561 When using Guix, each package ends up in the @dfn{package store}, in its
1562 own directory---something that resembles
1563 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1565 Instead of referring to these directories, users have their own
1566 @dfn{profile}, which points to the packages that they actually want to
1567 use. These profiles are stored within each user's home directory, at
1568 @code{$HOME/.guix-profile}.
1570 For example, @code{alice} installs GCC 4.7.2. As a result,
1571 @file{/home/alice/.guix-profile/bin/gcc} points to
1572 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1573 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1574 simply continues to point to
1575 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1576 coexist on the same system without any interference.
1578 The @command{guix package} command is the central tool to manage
1579 packages (@pxref{Invoking guix package}). It operates on the per-user
1580 profiles, and can be used @emph{with normal user privileges}.
1582 @cindex transactions
1583 The command provides the obvious install, remove, and upgrade
1584 operations. Each invocation is actually a @emph{transaction}: either
1585 the specified operation succeeds, or nothing happens. Thus, if the
1586 @command{guix package} process is terminated during the transaction,
1587 or if a power outage occurs during the transaction, then the user's
1588 profile remains in its previous state, and remains usable.
1590 In addition, any package transaction may be @emph{rolled back}. So, if,
1591 for example, an upgrade installs a new version of a package that turns
1592 out to have a serious bug, users may roll back to the previous instance
1593 of their profile, which was known to work well. Similarly, the global
1594 system configuration on GuixSD is subject to
1595 transactional upgrades and roll-back
1596 (@pxref{Using the Configuration System}).
1598 All packages in the package store may be @emph{garbage-collected}.
1599 Guix can determine which packages are still referenced by user
1600 profiles, and remove those that are provably no longer referenced
1601 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1602 generations of their profile so that the packages they refer to can be
1605 @cindex reproducibility
1606 @cindex reproducible builds
1607 Finally, Guix takes a @dfn{purely functional} approach to package
1608 management, as described in the introduction (@pxref{Introduction}).
1609 Each @file{/gnu/store} package directory name contains a hash of all the
1610 inputs that were used to build that package---compiler, libraries, build
1611 scripts, etc. This direct correspondence allows users to make sure a
1612 given package installation matches the current state of their
1613 distribution. It also helps maximize @dfn{build reproducibility}:
1614 thanks to the isolated build environments that are used, a given build
1615 is likely to yield bit-identical files when performed on different
1616 machines (@pxref{Invoking guix-daemon, container}).
1619 This foundation allows Guix to support @dfn{transparent binary/source
1620 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1621 available from an external source---a @dfn{substitute}, Guix just
1622 downloads it and unpacks it;
1623 otherwise, it builds the package from source, locally
1624 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1625 reproducible, users do not have to trust servers that provide
1626 substitutes: they can force a local build and @emph{challenge} providers
1627 (@pxref{Invoking guix challenge}).
1629 Control over the build environment is a feature that is also useful for
1630 developers. The @command{guix environment} command allows developers of
1631 a package to quickly set up the right development environment for their
1632 package, without having to manually install the dependencies of the
1633 package into their profile (@pxref{Invoking guix environment}).
1635 @node Invoking guix package
1636 @section Invoking @command{guix package}
1638 @cindex installing packages
1639 @cindex removing packages
1640 @cindex package installation
1641 @cindex package removal
1642 The @command{guix package} command is the tool that allows users to
1643 install, upgrade, and remove packages, as well as rolling back to
1644 previous configurations. It operates only on the user's own profile,
1645 and works with normal user privileges (@pxref{Features}). Its syntax
1649 guix package @var{options}
1651 @cindex transactions
1652 Primarily, @var{options} specifies the operations to be performed during
1653 the transaction. Upon completion, a new profile is created, but
1654 previous @dfn{generations} of the profile remain available, should the user
1657 For example, to remove @code{lua} and install @code{guile} and
1658 @code{guile-cairo} in a single transaction:
1661 guix package -r lua -i guile guile-cairo
1664 @command{guix package} also supports a @dfn{declarative approach}
1665 whereby the user specifies the exact set of packages to be available and
1666 passes it @i{via} the @option{--manifest} option
1667 (@pxref{profile-manifest, @option{--manifest}}).
1670 For each user, a symlink to the user's default profile is automatically
1671 created in @file{$HOME/.guix-profile}. This symlink always points to the
1672 current generation of the user's default profile. Thus, users can add
1673 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1674 variable, and so on.
1675 @cindex search paths
1676 If you are not using the Guix System Distribution, consider adding the
1677 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1678 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1679 shells get all the right environment variable definitions:
1682 GUIX_PROFILE="$HOME/.guix-profile" \
1683 source "$HOME/.guix-profile/etc/profile"
1686 In a multi-user setup, user profiles are stored in a place registered as
1687 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1688 to (@pxref{Invoking guix gc}). That directory is normally
1689 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1690 @var{localstatedir} is the value passed to @code{configure} as
1691 @code{--localstatedir}, and @var{user} is the user name. The
1692 @file{per-user} directory is created when @command{guix-daemon} is
1693 started, and the @var{user} sub-directory is created by @command{guix
1696 The @var{options} can be among the following:
1700 @item --install=@var{package} @dots{}
1701 @itemx -i @var{package} @dots{}
1702 Install the specified @var{package}s.
1704 Each @var{package} may specify either a simple package name, such as
1705 @code{guile}, or a package name followed by an at-sign and version number,
1706 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1707 case, the newest version prefixed by @code{1.8} is selected.)
1709 If no version number is specified, the
1710 newest available version will be selected. In addition, @var{package}
1711 may contain a colon, followed by the name of one of the outputs of the
1712 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1713 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1714 name (and optionally version) are searched for among the GNU
1715 distribution modules (@pxref{Package Modules}).
1717 @cindex propagated inputs
1718 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1719 that automatically get installed along with the required package
1720 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1721 @code{package} objects}, for information about propagated inputs in
1722 package definitions).
1724 @anchor{package-cmd-propagated-inputs}
1725 An example is the GNU MPC library: its C header files refer to those of
1726 the GNU MPFR library, which in turn refer to those of the GMP library.
1727 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1728 in the profile; removing MPC also removes MPFR and GMP---unless they had
1729 also been explicitly installed by the user.
1731 Besides, packages sometimes rely on the definition of environment
1732 variables for their search paths (see explanation of
1733 @code{--search-paths} below). Any missing or possibly incorrect
1734 environment variable definitions are reported here.
1736 @item --install-from-expression=@var{exp}
1738 Install the package @var{exp} evaluates to.
1740 @var{exp} must be a Scheme expression that evaluates to a
1741 @code{<package>} object. This option is notably useful to disambiguate
1742 between same-named variants of a package, with expressions such as
1743 @code{(@@ (gnu packages base) guile-final)}.
1745 Note that this option installs the first output of the specified
1746 package, which may be insufficient when needing a specific output of a
1747 multiple-output package.
1749 @item --install-from-file=@var{file}
1750 @itemx -f @var{file}
1751 Install the package that the code within @var{file} evaluates to.
1753 As an example, @var{file} might contain a definition like this
1754 (@pxref{Defining Packages}):
1757 @verbatiminclude package-hello.scm
1760 Developers may find it useful to include such a @file{guix.scm} file
1761 in the root of their project source tree that can be used to test
1762 development snapshots and create reproducible development environments
1763 (@pxref{Invoking guix environment}).
1765 @item --remove=@var{package} @dots{}
1766 @itemx -r @var{package} @dots{}
1767 Remove the specified @var{package}s.
1769 As for @code{--install}, each @var{package} may specify a version number
1770 and/or output name in addition to the package name. For instance,
1771 @code{-r glibc:debug} would remove the @code{debug} output of
1774 @item --upgrade[=@var{regexp} @dots{}]
1775 @itemx -u [@var{regexp} @dots{}]
1776 @cindex upgrading packages
1777 Upgrade all the installed packages. If one or more @var{regexp}s are
1778 specified, upgrade only installed packages whose name matches a
1779 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1781 Note that this upgrades package to the latest version of packages found
1782 in the distribution currently installed. To update your distribution,
1783 you should regularly run @command{guix pull} (@pxref{Invoking guix
1786 @item --do-not-upgrade[=@var{regexp} @dots{}]
1787 When used together with the @code{--upgrade} option, do @emph{not}
1788 upgrade any packages whose name matches a @var{regexp}. For example, to
1789 upgrade all packages in the current profile except those containing the
1790 substring ``emacs'':
1793 $ guix package --upgrade . --do-not-upgrade emacs
1796 @item @anchor{profile-manifest}--manifest=@var{file}
1797 @itemx -m @var{file}
1798 @cindex profile declaration
1799 @cindex profile manifest
1800 Create a new generation of the profile from the manifest object
1801 returned by the Scheme code in @var{file}.
1803 This allows you to @emph{declare} the profile's contents rather than
1804 constructing it through a sequence of @code{--install} and similar
1805 commands. The advantage is that @var{file} can be put under version
1806 control, copied to different machines to reproduce the same profile, and
1809 @c FIXME: Add reference to (guix profile) documentation when available.
1810 @var{file} must return a @dfn{manifest} object, which is roughly a list
1813 @findex packages->manifest
1815 (use-package-modules guile emacs)
1820 ;; Use a specific package output.
1821 (list guile-2.0 "debug")))
1824 @findex specifications->manifest
1825 In this example we have to know which modules define the @code{emacs}
1826 and @code{guile-2.0} variables to provide the right
1827 @code{use-package-modules} line, which can be cumbersome. We can
1828 instead provide regular package specifications and let
1829 @code{specifications->manifest} look up the corresponding package
1833 (specifications->manifest
1834 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1838 @cindex rolling back
1839 @cindex undoing transactions
1840 @cindex transactions, undoing
1841 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1842 the last transaction.
1844 When combined with options such as @code{--install}, roll back occurs
1845 before any other actions.
1847 When rolling back from the first generation that actually contains
1848 installed packages, the profile is made to point to the @dfn{zeroth
1849 generation}, which contains no files apart from its own metadata.
1851 After having rolled back, installing, removing, or upgrading packages
1852 overwrites previous future generations. Thus, the history of the
1853 generations in a profile is always linear.
1855 @item --switch-generation=@var{pattern}
1856 @itemx -S @var{pattern}
1858 Switch to a particular generation defined by @var{pattern}.
1860 @var{pattern} may be either a generation number or a number prefixed
1861 with ``+'' or ``-''. The latter means: move forward/backward by a
1862 specified number of generations. For example, if you want to return to
1863 the latest generation after @code{--roll-back}, use
1864 @code{--switch-generation=+1}.
1866 The difference between @code{--roll-back} and
1867 @code{--switch-generation=-1} is that @code{--switch-generation} will
1868 not make a zeroth generation, so if a specified generation does not
1869 exist, the current generation will not be changed.
1871 @item --search-paths[=@var{kind}]
1872 @cindex search paths
1873 Report environment variable definitions, in Bash syntax, that may be
1874 needed in order to use the set of installed packages. These environment
1875 variables are used to specify @dfn{search paths} for files used by some
1876 of the installed packages.
1878 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1879 environment variables to be defined so it can look for headers and
1880 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1881 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1882 library are installed in the profile, then @code{--search-paths} will
1883 suggest setting these variables to @code{@var{profile}/include} and
1884 @code{@var{profile}/lib}, respectively.
1886 The typical use case is to define these environment variables in the
1890 $ eval `guix package --search-paths`
1893 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1894 meaning that the returned environment variable definitions will either
1895 be exact settings, or prefixes or suffixes of the current value of these
1896 variables. When omitted, @var{kind} defaults to @code{exact}.
1898 This option can also be used to compute the @emph{combined} search paths
1899 of several profiles. Consider this example:
1902 $ guix package -p foo -i guile
1903 $ guix package -p bar -i guile-json
1904 $ guix package -p foo -p bar --search-paths
1907 The last command above reports about the @code{GUILE_LOAD_PATH}
1908 variable, even though, taken individually, neither @file{foo} nor
1909 @file{bar} would lead to that recommendation.
1912 @item --profile=@var{profile}
1913 @itemx -p @var{profile}
1914 Use @var{profile} instead of the user's default profile.
1917 Produce verbose output. In particular, emit the build log of the
1918 environment on the standard error port.
1921 Use the bootstrap Guile to build the profile. This option is only
1922 useful to distribution developers.
1926 In addition to these actions, @command{guix package} supports the
1927 following options to query the current state of a profile, or the
1928 availability of packages:
1932 @item --search=@var{regexp}
1933 @itemx -s @var{regexp}
1934 @cindex searching for packages
1935 List the available packages whose name, synopsis, or description matches
1936 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1937 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1938 GNU recutils manual}).
1940 This allows specific fields to be extracted using the @command{recsel}
1941 command, for instance:
1944 $ guix package -s malloc | recsel -p name,version,relevance
1958 Similarly, to show the name of all the packages available under the
1959 terms of the GNU@tie{}LGPL version 3:
1962 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1969 It is also possible to refine search results using several @code{-s}
1970 flags. For example, the following command returns a list of board
1974 $ guix package -s '\<board\>' -s game | recsel -p name
1979 If we were to omit @code{-s game}, we would also get software packages
1980 that deal with printed circuit boards; removing the angle brackets
1981 around @code{board} would further add packages that have to do with
1984 And now for a more elaborate example. The following command searches
1985 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1986 libraries, and prints the name and synopsis of the matching packages:
1989 $ guix package -s crypto -s library | \
1990 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1994 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1995 information on @dfn{selection expressions} for @code{recsel -e}.
1997 @item --show=@var{package}
1998 Show details about @var{package}, taken from the list of available packages, in
1999 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
2003 $ guix package --show=python | recsel -p name,version
2011 You may also specify the full name of a package to only get details about a
2012 specific version of it:
2014 $ guix package --show=python@@3.4 | recsel -p name,version
2021 @item --list-installed[=@var{regexp}]
2022 @itemx -I [@var{regexp}]
2023 List the currently installed packages in the specified profile, with the
2024 most recently installed packages shown last. When @var{regexp} is
2025 specified, list only installed packages whose name matches @var{regexp}.
2027 For each installed package, print the following items, separated by
2028 tabs: the package name, its version string, the part of the package that
2029 is installed (for instance, @code{out} for the default output,
2030 @code{include} for its headers, etc.), and the path of this package in
2033 @item --list-available[=@var{regexp}]
2034 @itemx -A [@var{regexp}]
2035 List packages currently available in the distribution for this system
2036 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
2037 installed packages whose name matches @var{regexp}.
2039 For each package, print the following items separated by tabs: its name,
2040 its version string, the parts of the package (@pxref{Packages with
2041 Multiple Outputs}), and the source location of its definition.
2043 @item --list-generations[=@var{pattern}]
2044 @itemx -l [@var{pattern}]
2046 Return a list of generations along with their creation dates; for each
2047 generation, show the installed packages, with the most recently
2048 installed packages shown last. Note that the zeroth generation is never
2051 For each installed package, print the following items, separated by
2052 tabs: the name of a package, its version string, the part of the package
2053 that is installed (@pxref{Packages with Multiple Outputs}), and the
2054 location of this package in the store.
2056 When @var{pattern} is used, the command returns only matching
2057 generations. Valid patterns include:
2060 @item @emph{Integers and comma-separated integers}. Both patterns denote
2061 generation numbers. For instance, @code{--list-generations=1} returns
2064 And @code{--list-generations=1,8,2} outputs three generations in the
2065 specified order. Neither spaces nor trailing commas are allowed.
2067 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2068 specified generations and everything in between. Note that the start of
2069 a range must be smaller than its end.
2071 It is also possible to omit the endpoint. For example,
2072 @code{--list-generations=2..}, returns all generations starting from the
2075 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2076 or months by passing an integer along with the first letter of the
2077 duration. For example, @code{--list-generations=20d} lists generations
2078 that are up to 20 days old.
2081 @item --delete-generations[=@var{pattern}]
2082 @itemx -d [@var{pattern}]
2083 When @var{pattern} is omitted, delete all generations except the current
2086 This command accepts the same patterns as @option{--list-generations}.
2087 When @var{pattern} is specified, delete the matching generations. When
2088 @var{pattern} specifies a duration, generations @emph{older} than the
2089 specified duration match. For instance, @code{--delete-generations=1m}
2090 deletes generations that are more than one month old.
2092 If the current generation matches, it is @emph{not} deleted. Also, the
2093 zeroth generation is never deleted.
2095 Note that deleting generations prevents rolling back to them.
2096 Consequently, this command must be used with care.
2100 Finally, since @command{guix package} may actually start build
2101 processes, it supports all the common build options (@pxref{Common Build
2102 Options}). It also supports package transformation options, such as
2103 @option{--with-source} (@pxref{Package Transformation Options}).
2104 However, note that package transformations are lost when upgrading; to
2105 preserve transformations across upgrades, you should define your own
2106 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2107 (@pxref{Defining Packages}).
2111 @section Substitutes
2114 @cindex pre-built binaries
2115 Guix supports transparent source/binary deployment, which means that it
2116 can either build things locally, or download pre-built items from a
2117 server. We call these pre-built items @dfn{substitutes}---they are
2118 substitutes for local build results. In many cases, downloading a
2119 substitute is much faster than building things locally.
2121 Substitutes can be anything resulting from a derivation build
2122 (@pxref{Derivations}). Of course, in the common case, they are
2123 pre-built package binaries, but source tarballs, for instance, which
2124 also result from derivation builds, can be available as substitutes.
2126 The @code{hydra.gnu.org} server is a front-end to a build farm that
2127 builds packages from the GNU distribution continuously for some
2128 architectures, and makes them available as substitutes. This is the
2129 default source of substitutes; it can be overridden by passing the
2130 @option{--substitute-urls} option either to @command{guix-daemon}
2131 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2132 or to client tools such as @command{guix package}
2133 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2136 Substitute URLs can be either HTTP or HTTPS.
2137 HTTPS is recommended because communications are encrypted; conversely,
2138 using HTTP makes all communications visible to an eavesdropper, who
2139 could use the information gathered to determine, for instance, whether
2140 your system has unpatched security vulnerabilities.
2143 @cindex digital signatures
2144 @cindex substitutes, authorization thereof
2145 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2147 must add its public key to the access control list (ACL) of archive
2148 imports, using the @command{guix archive} command (@pxref{Invoking guix
2149 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2150 be compromised and to serve genuine substitutes.
2152 This public key is installed along with Guix, in
2153 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2154 the installation prefix of Guix. If you installed Guix from source,
2155 make sure you checked the GPG signature of
2156 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2157 Then, you can run something like this:
2160 # guix archive --authorize < hydra.gnu.org.pub
2163 Once this is in place, the output of a command like @code{guix build}
2164 should change from something like:
2167 $ guix build emacs --dry-run
2168 The following derivations would be built:
2169 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2170 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2171 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2172 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2180 $ guix build emacs --dry-run
2181 The following files would be downloaded:
2182 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2183 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2184 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2185 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2190 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2191 will be downloaded, when possible, for future builds.
2193 Guix ignores substitutes that are not signed, or that are not signed by
2194 one of the keys listed in the ACL. It also detects and raises an error
2195 when attempting to use a substitute that has been tampered with.
2198 Substitutes are downloaded over HTTP or HTTPS.
2199 The @code{http_proxy} environment
2200 variable can be set in the environment of @command{guix-daemon} and is
2201 honored for downloads of substitutes. Note that the value of
2202 @code{http_proxy} in the environment where @command{guix build},
2203 @command{guix package}, and other client commands are run has
2204 @emph{absolutely no effect}.
2206 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2207 (in other words, the server is not authenticated), contrary to what
2208 HTTPS clients such as Web browsers usually do. This is because Guix
2209 authenticates substitute information itself, as explained above, which
2210 is what we care about (whereas X.509 certificates are about
2211 authenticating bindings between domain names and public keys.)
2213 You can get statistics on the substitutes provided by a server using the
2214 @command{guix weather} command (@pxref{Invoking guix weather}).
2216 The substitute mechanism can be disabled globally by running
2217 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2218 guix-daemon}). It can also be disabled temporarily by passing the
2219 @code{--no-substitutes} option to @command{guix package}, @command{guix
2220 build}, and other command-line tools.
2223 @unnumberedsubsec On Trusting Binaries
2225 Today, each individual's control over their own computing is at the
2226 mercy of institutions, corporations, and groups with enough power and
2227 determination to subvert the computing infrastructure and exploit its
2228 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2229 convenient, we encourage users to also build on their own, or even run
2230 their own build farm, such that @code{hydra.gnu.org} is less of an
2231 interesting target. One way to help is by publishing the software you
2232 build using @command{guix publish} so that others have one more choice
2233 of server to download substitutes from (@pxref{Invoking guix publish}).
2235 Guix has the foundations to maximize build reproducibility
2236 (@pxref{Features}). In most cases, independent builds of a given
2237 package or derivation should yield bit-identical results. Thus, through
2238 a diverse set of independent package builds, we can strengthen the
2239 integrity of our systems. The @command{guix challenge} command aims to
2240 help users assess substitute servers, and to assist developers in
2241 finding out about non-deterministic package builds (@pxref{Invoking guix
2242 challenge}). Similarly, the @option{--check} option of @command{guix
2243 build} allows users to check whether previously-installed substitutes
2244 are genuine by rebuilding them locally (@pxref{build-check,
2245 @command{guix build --check}}).
2247 In the future, we want Guix to have support to publish and retrieve
2248 binaries to/from other users, in a peer-to-peer fashion. If you would
2249 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2252 @node Packages with Multiple Outputs
2253 @section Packages with Multiple Outputs
2255 @cindex multiple-output packages
2256 @cindex package outputs
2259 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2260 source package leads to exactly one directory in the store. When running
2261 @command{guix package -i glibc}, one installs the default output of the
2262 GNU libc package; the default output is called @code{out}, but its name
2263 can be omitted as shown in this command. In this particular case, the
2264 default output of @code{glibc} contains all the C header files, shared
2265 libraries, static libraries, Info documentation, and other supporting
2268 Sometimes it is more appropriate to separate the various types of files
2269 produced from a single source package into separate outputs. For
2270 instance, the GLib C library (used by GTK+ and related packages)
2271 installs more than 20 MiB of reference documentation as HTML pages.
2272 To save space for users who do not need it, the documentation goes to a
2273 separate output, called @code{doc}. To install the main GLib output,
2274 which contains everything but the documentation, one would run:
2277 guix package -i glib
2280 @cindex documentation
2281 The command to install its documentation is:
2284 guix package -i glib:doc
2287 Some packages install programs with different ``dependency footprints''.
2288 For instance, the WordNet package installs both command-line tools and
2289 graphical user interfaces (GUIs). The former depend solely on the C
2290 library, whereas the latter depend on Tcl/Tk and the underlying X
2291 libraries. In this case, we leave the command-line tools in the default
2292 output, whereas the GUIs are in a separate output. This allows users
2293 who do not need the GUIs to save space. The @command{guix size} command
2294 can help find out about such situations (@pxref{Invoking guix size}).
2295 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2297 There are several such multiple-output packages in the GNU distribution.
2298 Other conventional output names include @code{lib} for libraries and
2299 possibly header files, @code{bin} for stand-alone programs, and
2300 @code{debug} for debugging information (@pxref{Installing Debugging
2301 Files}). The outputs of a packages are listed in the third column of
2302 the output of @command{guix package --list-available} (@pxref{Invoking
2306 @node Invoking guix gc
2307 @section Invoking @command{guix gc}
2309 @cindex garbage collector
2311 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2312 The @command{guix gc} command allows users to explicitly run the garbage
2313 collector to reclaim space from the @file{/gnu/store} directory. It is
2314 the @emph{only} way to remove files from @file{/gnu/store}---removing
2315 files or directories manually may break it beyond repair!
2317 The garbage collector has a set of known @dfn{roots}: any file under
2318 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2319 cannot be deleted; any other file is considered @dfn{dead} and may be
2320 deleted. The set of garbage collector roots includes default user
2321 profiles, and may be augmented with @command{guix build --root}, for
2322 example (@pxref{Invoking guix build}).
2324 Prior to running @code{guix gc --collect-garbage} to make space, it is
2325 often useful to remove old generations from user profiles; that way, old
2326 package builds referenced by those generations can be reclaimed. This
2327 is achieved by running @code{guix package --delete-generations}
2328 (@pxref{Invoking guix package}).
2330 Our recommendation is to run a garbage collection periodically, or when
2331 you are short on disk space. For instance, to guarantee that at least
2332 5@tie{}GB are available on your disk, simply run:
2338 It is perfectly safe to run as a non-interactive periodic job
2339 (@pxref{Scheduled Job Execution}, for how to set up such a job on
2340 GuixSD). Running @command{guix gc} with no arguments will collect as
2341 much garbage as it can, but that is often inconvenient: you may find
2342 yourself having to rebuild or re-download software that is ``dead'' from
2343 the GC viewpoint but that is necessary to build other pieces of
2344 software---e.g., the compiler tool chain.
2346 The @command{guix gc} command has three modes of operation: it can be
2347 used to garbage-collect any dead files (the default), to delete specific
2348 files (the @code{--delete} option), to print garbage-collector
2349 information, or for more advanced queries. The garbage collection
2350 options are as follows:
2353 @item --collect-garbage[=@var{min}]
2354 @itemx -C [@var{min}]
2355 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2356 sub-directories. This is the default operation when no option is
2359 When @var{min} is given, stop once @var{min} bytes have been collected.
2360 @var{min} may be a number of bytes, or it may include a unit as a
2361 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2362 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2364 When @var{min} is omitted, collect all the garbage.
2366 @item --free-space=@var{free}
2367 @itemx -F @var{free}
2368 Collect garbage until @var{free} space is available under
2369 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2370 as @code{500MiB}, as described above.
2372 When @var{free} or more is already available in @file{/gnu/store}, do
2373 nothing and exit immediately.
2377 Attempt to delete all the store files and directories specified as
2378 arguments. This fails if some of the files are not in the store, or if
2379 they are still live.
2381 @item --list-failures
2382 List store items corresponding to cached build failures.
2384 This prints nothing unless the daemon was started with
2385 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2386 @option{--cache-failures}}).
2388 @item --clear-failures
2389 Remove the specified store items from the failed-build cache.
2391 Again, this option only makes sense when the daemon is started with
2392 @option{--cache-failures}. Otherwise, it does nothing.
2395 Show the list of dead files and directories still present in the
2396 store---i.e., files and directories no longer reachable from any root.
2399 Show the list of live store files and directories.
2403 In addition, the references among existing store files can be queried:
2409 @cindex package dependencies
2410 List the references (respectively, the referrers) of store files given
2416 List the requisites of the store files passed as arguments. Requisites
2417 include the store files themselves, their references, and the references
2418 of these, recursively. In other words, the returned list is the
2419 @dfn{transitive closure} of the store files.
2421 @xref{Invoking guix size}, for a tool to profile the size of the closure
2422 of an element. @xref{Invoking guix graph}, for a tool to visualize
2423 the graph of references.
2427 Lastly, the following options allow you to check the integrity of the
2428 store and to control disk usage.
2432 @item --verify[=@var{options}]
2433 @cindex integrity, of the store
2434 @cindex integrity checking
2435 Verify the integrity of the store.
2437 By default, make sure that all the store items marked as valid in the
2438 database of the daemon actually exist in @file{/gnu/store}.
2440 When provided, @var{options} must be a comma-separated list containing one
2441 or more of @code{contents} and @code{repair}.
2443 When passing @option{--verify=contents}, the daemon computes the
2444 content hash of each store item and compares it against its hash in the
2445 database. Hash mismatches are reported as data corruptions. Because it
2446 traverses @emph{all the files in the store}, this command can take a
2447 long time, especially on systems with a slow disk drive.
2449 @cindex repairing the store
2450 @cindex corruption, recovering from
2451 Using @option{--verify=repair} or @option{--verify=contents,repair}
2452 causes the daemon to try to repair corrupt store items by fetching
2453 substitutes for them (@pxref{Substitutes}). Because repairing is not
2454 atomic, and thus potentially dangerous, it is available only to the
2455 system administrator. A lightweight alternative, when you know exactly
2456 which items in the store are corrupt, is @command{guix build --repair}
2457 (@pxref{Invoking guix build}).
2460 @cindex deduplication
2461 Optimize the store by hard-linking identical files---this is
2462 @dfn{deduplication}.
2464 The daemon performs deduplication after each successful build or archive
2465 import, unless it was started with @code{--disable-deduplication}
2466 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2467 this option is primarily useful when the daemon was running with
2468 @code{--disable-deduplication}.
2472 @node Invoking guix pull
2473 @section Invoking @command{guix pull}
2475 @cindex upgrading Guix
2476 @cindex updating Guix
2477 @cindex @command{guix pull}
2479 Packages are installed or upgraded to the latest version available in
2480 the distribution currently available on your local machine. To update
2481 that distribution, along with the Guix tools, you must run @command{guix
2482 pull}: the command downloads the latest Guix source code and package
2483 descriptions, and deploys it. Source code is downloaded from a
2484 @uref{https://git-scm.com, Git} repository.
2486 On completion, @command{guix package} will use packages and package
2487 versions from this just-retrieved copy of Guix. Not only that, but all
2488 the Guix commands and Scheme modules will also be taken from that latest
2489 version. New @command{guix} sub-commands added by the update also
2492 Any user can update their Guix copy using @command{guix pull}, and the
2493 effect is limited to the user who run @command{guix pull}. For
2494 instance, when user @code{root} runs @command{guix pull}, this has no
2495 effect on the version of Guix that user @code{alice} sees, and vice
2496 versa@footnote{Under the hood, @command{guix pull} updates the
2497 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2498 and the @command{guix} command loads code from there. Currently, the
2499 only way to roll back an invocation of @command{guix pull} is to
2500 manually update this symlink to point to the previous Guix.}.
2502 The @command{guix pull} command is usually invoked with no arguments,
2503 but it supports the following options:
2507 Produce verbose output, writing build logs to the standard error output.
2509 @item --url=@var{url}
2510 Download Guix from the Git repository at @var{url}.
2512 By default, the source is taken from its canonical Git repository at
2513 @code{gnu.org}, for the stable branch of Guix.
2515 @item --commit=@var{commit}
2516 Deploy @var{commit}, a valid Git commit ID represented as a hexadecimal
2519 @item --branch=@var{branch}
2520 Deploy the tip of @var{branch}, the name of a Git branch available on
2521 the repository at @var{url}.
2524 Use the bootstrap Guile to build the latest Guix. This option is only
2525 useful to Guix developers.
2528 In addition, @command{guix pull} supports all the common build options
2529 (@pxref{Common Build Options}).
2531 @node Invoking guix pack
2532 @section Invoking @command{guix pack}
2534 Occasionally you want to pass software to people who are not (yet!)
2535 lucky enough to be using Guix. You'd tell them to run @command{guix
2536 package -i @var{something}}, but that's not possible in this case. This
2537 is where @command{guix pack} comes in.
2541 @cindex application bundle
2542 @cindex software bundle
2543 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2544 @dfn{software bundle}: it creates a tarball or some other archive
2545 containing the binaries of the software you're interested in, and all
2546 its dependencies. The resulting archive can be used on any machine that
2547 does not have Guix, and people can run the exact same binaries as those
2548 you have with Guix. The pack itself is created in a bit-reproducible
2549 fashion, so anyone can verify that it really contains the build results
2550 that you pretend to be shipping.
2552 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2553 their dependencies, you can run:
2556 $ guix pack guile emacs geiser
2558 /gnu/store/@dots{}-pack.tar.gz
2561 The result here is a tarball containing a @file{/gnu/store} directory
2562 with all the relevant packages. The resulting tarball contains a
2563 @dfn{profile} with the three packages of interest; the profile is the
2564 same as would be created by @command{guix package -i}. It is this
2565 mechanism that is used to create Guix's own standalone binary tarball
2566 (@pxref{Binary Installation}).
2568 Users of this pack would have to run
2569 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2570 find inconvenient. To work around it, you can create, say, a
2571 @file{/opt/gnu/bin} symlink to the profile:
2574 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2578 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2580 Alternatively, you can produce a pack in the Docker image format using
2581 the following command:
2584 guix pack -f docker guile emacs geiser
2588 The result is a tarball that can be passed to the @command{docker load}
2590 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2591 documentation} for more information.
2593 Several command-line options allow you to customize your pack:
2596 @item --format=@var{format}
2597 @itemx -f @var{format}
2598 Produce a pack in the given @var{format}.
2600 The available formats are:
2604 This is the default format. It produces a tarball containing all the
2605 specified binaries and symlinks.
2608 This produces a tarball that follows the
2609 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2610 Docker Image Specification}.
2613 @item --expression=@var{expr}
2614 @itemx -e @var{expr}
2615 Consider the package @var{expr} evaluates to.
2617 This has the same purpose as the same-named option in @command{guix
2618 build} (@pxref{Additional Build Options, @code{--expression} in
2619 @command{guix build}}).
2621 @item --system=@var{system}
2622 @itemx -s @var{system}
2623 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2624 the system type of the build host.
2626 @item --target=@var{triplet}
2627 @cindex cross-compilation
2628 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2629 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2630 configuration triplets,, autoconf, Autoconf}).
2632 @item --compression=@var{tool}
2633 @itemx -C @var{tool}
2634 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2635 @code{bzip2}, @code{xz}, @code{lzip}, or @code{none} for no compression.
2637 @item --symlink=@var{spec}
2638 @itemx -S @var{spec}
2639 Add the symlinks specified by @var{spec} to the pack. This option can
2640 appear several times.
2642 @var{spec} has the form @code{@var{source}=@var{target}}, where
2643 @var{source} is the symlink that will be created and @var{target} is the
2646 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2647 symlink pointing to the @file{bin} sub-directory of the profile.
2649 @item --localstatedir
2650 Include the ``local state directory'', @file{/var/guix}, in the
2653 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2654 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2655 the pack means that the store is ``complete'' and manageable by Guix;
2656 not providing it pack means that the store is ``dead'': items cannot be
2657 added to it or removed from it after extraction of the pack.
2659 One use case for this is the Guix self-contained binary tarball
2660 (@pxref{Binary Installation}).
2663 In addition, @command{guix pack} supports all the common build options
2664 (@pxref{Common Build Options}) and all the package transformation
2665 options (@pxref{Package Transformation Options}).
2668 @node Invoking guix archive
2669 @section Invoking @command{guix archive}
2671 @cindex @command{guix archive}
2673 The @command{guix archive} command allows users to @dfn{export} files
2674 from the store into a single archive, and to later @dfn{import} them.
2675 In particular, it allows store files to be transferred from one machine
2676 to the store on another machine.
2678 @cindex exporting store items
2679 To export store files as an archive to standard output, run:
2682 guix archive --export @var{options} @var{specifications}...
2685 @var{specifications} may be either store file names or package
2686 specifications, as for @command{guix package} (@pxref{Invoking guix
2687 package}). For instance, the following command creates an archive
2688 containing the @code{gui} output of the @code{git} package and the main
2689 output of @code{emacs}:
2692 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2695 If the specified packages are not built yet, @command{guix archive}
2696 automatically builds them. The build process may be controlled with the
2697 common build options (@pxref{Common Build Options}).
2699 To transfer the @code{emacs} package to a machine connected over SSH,
2703 guix archive --export -r emacs | ssh the-machine guix archive --import
2707 Similarly, a complete user profile may be transferred from one machine
2708 to another like this:
2711 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2712 ssh the-machine guix-archive --import
2716 However, note that, in both examples, all of @code{emacs} and the
2717 profile as well as all of their dependencies are transferred (due to
2718 @code{-r}), regardless of what is already available in the store on the
2719 target machine. The @code{--missing} option can help figure out which
2720 items are missing from the target store. The @command{guix copy}
2721 command simplifies and optimizes this whole process, so this is probably
2722 what you should use in this case (@pxref{Invoking guix copy}).
2724 @cindex nar, archive format
2725 @cindex normalized archive (nar)
2726 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2727 comparable in spirit to `tar', but with differences
2728 that make it more appropriate for our purposes. First, rather than
2729 recording all Unix metadata for each file, the nar format only mentions
2730 the file type (regular, directory, or symbolic link); Unix permissions
2731 and owner/group are dismissed. Second, the order in which directory
2732 entries are stored always follows the order of file names according to
2733 the C locale collation order. This makes archive production fully
2736 When exporting, the daemon digitally signs the contents of the archive,
2737 and that digital signature is appended. When importing, the daemon
2738 verifies the signature and rejects the import in case of an invalid
2739 signature or if the signing key is not authorized.
2740 @c FIXME: Add xref to daemon doc about signatures.
2742 The main options are:
2746 Export the specified store files or packages (see below.) Write the
2747 resulting archive to the standard output.
2749 Dependencies are @emph{not} included in the output, unless
2750 @code{--recursive} is passed.
2754 When combined with @code{--export}, this instructs @command{guix
2755 archive} to include dependencies of the given items in the archive.
2756 Thus, the resulting archive is self-contained: it contains the closure
2757 of the exported store items.
2760 Read an archive from the standard input, and import the files listed
2761 therein into the store. Abort if the archive has an invalid digital
2762 signature, or if it is signed by a public key not among the authorized
2763 keys (see @code{--authorize} below.)
2766 Read a list of store file names from the standard input, one per line,
2767 and write on the standard output the subset of these files missing from
2770 @item --generate-key[=@var{parameters}]
2771 @cindex signing, archives
2772 Generate a new key pair for the daemon. This is a prerequisite before
2773 archives can be exported with @code{--export}. Note that this operation
2774 usually takes time, because it needs to gather enough entropy to
2775 generate the key pair.
2777 The generated key pair is typically stored under @file{/etc/guix}, in
2778 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2779 key, which must be kept secret.) When @var{parameters} is omitted,
2780 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2781 versions before 1.6.0, it is a 4096-bit RSA key.
2782 Alternatively, @var{parameters} can specify
2783 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2784 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2785 Libgcrypt Reference Manual}).
2788 @cindex authorizing, archives
2789 Authorize imports signed by the public key passed on standard input.
2790 The public key must be in ``s-expression advanced format''---i.e., the
2791 same format as the @file{signing-key.pub} file.
2793 The list of authorized keys is kept in the human-editable file
2794 @file{/etc/guix/acl}. The file contains
2795 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2796 s-expressions''} and is structured as an access-control list in the
2797 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2800 @item --extract=@var{directory}
2801 @itemx -x @var{directory}
2802 Read a single-item archive as served by substitute servers
2803 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2804 low-level operation needed in only very narrow use cases; see below.
2806 For example, the following command extracts the substitute for Emacs
2807 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2811 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2812 | bunzip2 | guix archive -x /tmp/emacs
2815 Single-item archives are different from multiple-item archives produced
2816 by @command{guix archive --export}; they contain a single store item,
2817 and they do @emph{not} embed a signature. Thus this operation does
2818 @emph{no} signature verification and its output should be considered
2821 The primary purpose of this operation is to facilitate inspection of
2822 archive contents coming from possibly untrusted substitute servers.
2826 @c *********************************************************************
2827 @node Programming Interface
2828 @chapter Programming Interface
2830 GNU Guix provides several Scheme programming interfaces (APIs) to
2831 define, build, and query packages. The first interface allows users to
2832 write high-level package definitions. These definitions refer to
2833 familiar packaging concepts, such as the name and version of a package,
2834 its build system, and its dependencies. These definitions can then be
2835 turned into concrete build actions.
2837 Build actions are performed by the Guix daemon, on behalf of users. In a
2838 standard setup, the daemon has write access to the store---the
2839 @file{/gnu/store} directory---whereas users do not. The recommended
2840 setup also has the daemon perform builds in chroots, under a specific
2841 build users, to minimize interference with the rest of the system.
2844 Lower-level APIs are available to interact with the daemon and the
2845 store. To instruct the daemon to perform a build action, users actually
2846 provide it with a @dfn{derivation}. A derivation is a low-level
2847 representation of the build actions to be taken, and the environment in
2848 which they should occur---derivations are to package definitions what
2849 assembly is to C programs. The term ``derivation'' comes from the fact
2850 that build results @emph{derive} from them.
2852 This chapter describes all these APIs in turn, starting from high-level
2853 package definitions.
2856 * Defining Packages:: Defining new packages.
2857 * Build Systems:: Specifying how packages are built.
2858 * The Store:: Manipulating the package store.
2859 * Derivations:: Low-level interface to package derivations.
2860 * The Store Monad:: Purely functional interface to the store.
2861 * G-Expressions:: Manipulating build expressions.
2864 @node Defining Packages
2865 @section Defining Packages
2867 The high-level interface to package definitions is implemented in the
2868 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2869 example, the package definition, or @dfn{recipe}, for the GNU Hello
2870 package looks like this:
2873 (define-module (gnu packages hello)
2874 #:use-module (guix packages)
2875 #:use-module (guix download)
2876 #:use-module (guix build-system gnu)
2877 #:use-module (guix licenses)
2878 #:use-module (gnu packages gawk))
2880 (define-public hello
2886 (uri (string-append "mirror://gnu/hello/hello-" version
2890 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2891 (build-system gnu-build-system)
2892 (arguments '(#:configure-flags '("--enable-silent-rules")))
2893 (inputs `(("gawk" ,gawk)))
2894 (synopsis "Hello, GNU world: An example GNU package")
2895 (description "Guess what GNU Hello prints!")
2896 (home-page "http://www.gnu.org/software/hello/")
2901 Without being a Scheme expert, the reader may have guessed the meaning
2902 of the various fields here. This expression binds the variable
2903 @code{hello} to a @code{<package>} object, which is essentially a record
2904 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2905 This package object can be inspected using procedures found in the
2906 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2907 returns---surprise!---@code{"hello"}.
2909 With luck, you may be able to import part or all of the definition of
2910 the package you are interested in from another repository, using the
2911 @code{guix import} command (@pxref{Invoking guix import}).
2913 In the example above, @var{hello} is defined in a module of its own,
2914 @code{(gnu packages hello)}. Technically, this is not strictly
2915 necessary, but it is convenient to do so: all the packages defined in
2916 modules under @code{(gnu packages @dots{})} are automatically known to
2917 the command-line tools (@pxref{Package Modules}).
2919 There are a few points worth noting in the above package definition:
2923 The @code{source} field of the package is an @code{<origin>} object
2924 (@pxref{origin Reference}, for the complete reference).
2925 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2926 meaning that the source is a file to be downloaded over FTP or HTTP.
2928 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2929 the GNU mirrors defined in @code{(guix download)}.
2931 The @code{sha256} field specifies the expected SHA256 hash of the file
2932 being downloaded. It is mandatory, and allows Guix to check the
2933 integrity of the file. The @code{(base32 @dots{})} form introduces the
2934 base32 representation of the hash. You can obtain this information with
2935 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2936 hash} (@pxref{Invoking guix hash}).
2939 When needed, the @code{origin} form can also have a @code{patches} field
2940 listing patches to be applied, and a @code{snippet} field giving a
2941 Scheme expression to modify the source code.
2944 @cindex GNU Build System
2945 The @code{build-system} field specifies the procedure to build the
2946 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2947 represents the familiar GNU Build System, where packages may be
2948 configured, built, and installed with the usual @code{./configure &&
2949 make && make check && make install} command sequence.
2952 The @code{arguments} field specifies options for the build system
2953 (@pxref{Build Systems}). Here it is interpreted by
2954 @var{gnu-build-system} as a request run @file{configure} with the
2955 @code{--enable-silent-rules} flag.
2961 What about these quote (@code{'}) characters? They are Scheme syntax to
2962 introduce a literal list; @code{'} is synonymous with @code{quote}.
2963 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2964 for details. Here the value of the @code{arguments} field is a list of
2965 arguments passed to the build system down the road, as with @code{apply}
2966 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2969 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2970 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2971 @code{#:configure-flags} is a keyword used to pass a keyword argument
2972 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2976 The @code{inputs} field specifies inputs to the build process---i.e.,
2977 build-time or run-time dependencies of the package. Here, we define an
2978 input called @code{"gawk"} whose value is that of the @var{gawk}
2979 variable; @var{gawk} is itself bound to a @code{<package>} object.
2981 @cindex backquote (quasiquote)
2984 @cindex comma (unquote)
2988 @findex unquote-splicing
2989 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2990 us to introduce a literal list in the @code{inputs} field, while
2991 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2992 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2995 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2996 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2997 of ensuring that they are present (@pxref{Build Systems}).
2999 However, any other dependencies need to be specified in the
3000 @code{inputs} field. Any dependency not specified here will simply be
3001 unavailable to the build process, possibly leading to a build failure.
3004 @xref{package Reference}, for a full description of possible fields.
3006 Once a package definition is in place, the
3007 package may actually be built using the @code{guix build} command-line
3008 tool (@pxref{Invoking guix build}), troubleshooting any build failures
3009 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
3010 package definition using the @command{guix edit} command
3011 (@pxref{Invoking guix edit}).
3012 @xref{Packaging Guidelines}, for
3013 more information on how to test package definitions, and
3014 @ref{Invoking guix lint}, for information on how to check a definition
3015 for style conformance.
3016 @vindex GUIX_PACKAGE_PATH
3017 Lastly, @pxref{Package Modules}, for information
3018 on how to extend the distribution by adding your own package definitions
3019 to @code{GUIX_PACKAGE_PATH}.
3021 Finally, updating the package definition to a new upstream version
3022 can be partly automated by the @command{guix refresh} command
3023 (@pxref{Invoking guix refresh}).
3025 Behind the scenes, a derivation corresponding to the @code{<package>}
3026 object is first computed by the @code{package-derivation} procedure.
3027 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
3028 The build actions it prescribes may then be realized by using the
3029 @code{build-derivations} procedure (@pxref{The Store}).
3031 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
3032 Return the @code{<derivation>} object of @var{package} for @var{system}
3033 (@pxref{Derivations}).
3035 @var{package} must be a valid @code{<package>} object, and @var{system}
3036 must be a string denoting the target system type---e.g.,
3037 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
3038 must be a connection to the daemon, which operates on the store
3039 (@pxref{The Store}).
3043 @cindex cross-compilation
3044 Similarly, it is possible to compute a derivation that cross-builds a
3045 package for some other system:
3047 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
3048 @var{package} @var{target} [@var{system}]
3049 Return the @code{<derivation>} object of @var{package} cross-built from
3050 @var{system} to @var{target}.
3052 @var{target} must be a valid GNU triplet denoting the target hardware
3053 and operating system, such as @code{"mips64el-linux-gnu"}
3054 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
3055 Configure and Build System}).
3058 @cindex package transformations
3059 @cindex input rewriting
3060 @cindex dependency tree rewriting
3061 Packages can be manipulated in arbitrary ways. An example of a useful
3062 transformation is @dfn{input rewriting}, whereby the dependency tree of
3063 a package is rewritten by replacing specific inputs by others:
3065 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
3066 [@var{rewrite-name}]
3067 Return a procedure that, when passed a package, replaces its direct and
3068 indirect dependencies (but not its implicit inputs) according to
3069 @var{replacements}. @var{replacements} is a list of package pairs; the
3070 first element of each pair is the package to replace, and the second one
3073 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3074 the name of a package and returns its new name after rewrite.
3078 Consider this example:
3081 (define libressl-instead-of-openssl
3082 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3084 (package-input-rewriting `((,openssl . ,libressl))))
3086 (define git-with-libressl
3087 (libressl-instead-of-openssl git))
3091 Here we first define a rewriting procedure that replaces @var{openssl}
3092 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3093 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3094 This is exactly what the @option{--with-input} command-line option does
3095 (@pxref{Package Transformation Options, @option{--with-input}}).
3097 A more generic procedure to rewrite a package dependency graph is
3098 @code{package-mapping}: it supports arbitrary changes to nodes in the
3101 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3102 Return a procedure that, given a package, applies @var{proc} to all the packages
3103 depended on and returns the resulting package. The procedure stops recursion
3104 when @var{cut?} returns true for a given package.
3108 * package Reference :: The package data type.
3109 * origin Reference:: The origin data type.
3113 @node package Reference
3114 @subsection @code{package} Reference
3116 This section summarizes all the options available in @code{package}
3117 declarations (@pxref{Defining Packages}).
3119 @deftp {Data Type} package
3120 This is the data type representing a package recipe.
3124 The name of the package, as a string.
3126 @item @code{version}
3127 The version of the package, as a string.
3130 An object telling how the source code for the package should be
3131 acquired. Most of the time, this is an @code{origin} object, which
3132 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3133 can also be any other ``file-like'' object such as a @code{local-file},
3134 which denotes a file from the local file system (@pxref{G-Expressions,
3135 @code{local-file}}).
3137 @item @code{build-system}
3138 The build system that should be used to build the package (@pxref{Build
3141 @item @code{arguments} (default: @code{'()})
3142 The arguments that should be passed to the build system. This is a
3143 list, typically containing sequential keyword-value pairs.
3145 @item @code{inputs} (default: @code{'()})
3146 @itemx @code{native-inputs} (default: @code{'()})
3147 @itemx @code{propagated-inputs} (default: @code{'()})
3148 @cindex inputs, of packages
3149 These fields list dependencies of the package. Each one is a list of
3150 tuples, where each tuple has a label for the input (a string) as its
3151 first element, a package, origin, or derivation as its second element,
3152 and optionally the name of the output thereof that should be used, which
3153 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3154 more on package outputs). For example, the list below specifies three
3158 `(("libffi" ,libffi)
3159 ("libunistring" ,libunistring)
3160 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3163 @cindex cross compilation, package dependencies
3164 The distinction between @code{native-inputs} and @code{inputs} is
3165 necessary when considering cross-compilation. When cross-compiling,
3166 dependencies listed in @code{inputs} are built for the @emph{target}
3167 architecture; conversely, dependencies listed in @code{native-inputs}
3168 are built for the architecture of the @emph{build} machine.
3170 @code{native-inputs} is typically used to list tools needed at
3171 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3172 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3173 this area (@pxref{Invoking guix lint}).
3175 @anchor{package-propagated-inputs}
3176 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3177 specified packages will be automatically installed alongside the package
3178 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3179 package}}, for information on how @command{guix package} deals with
3182 For example this is necessary when a C/C++ library needs headers of
3183 another library to compile, or when a pkg-config file refers to another
3184 one @i{via} its @code{Requires} field.
3186 Another example where @code{propagated-inputs} is useful is for languages
3187 that lack a facility to record the run-time search path akin to the
3188 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3189 more. To ensure that libraries written in those languages can find
3190 library code they depend on at run time, run-time dependencies must be
3191 listed in @code{propagated-inputs} rather than @code{inputs}.
3193 @item @code{self-native-input?} (default: @code{#f})
3194 This is a Boolean field telling whether the package should use itself as
3195 a native input when cross-compiling.
3197 @item @code{outputs} (default: @code{'("out")})
3198 The list of output names of the package. @xref{Packages with Multiple
3199 Outputs}, for typical uses of additional outputs.
3201 @item @code{native-search-paths} (default: @code{'()})
3202 @itemx @code{search-paths} (default: @code{'()})
3203 A list of @code{search-path-specification} objects describing
3204 search-path environment variables honored by the package.
3206 @item @code{replacement} (default: @code{#f})
3207 This must be either @code{#f} or a package object that will be used as a
3208 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3211 @item @code{synopsis}
3212 A one-line description of the package.
3214 @item @code{description}
3215 A more elaborate description of the package.
3217 @item @code{license}
3218 @cindex license, of packages
3219 The license of the package; a value from @code{(guix licenses)},
3220 or a list of such values.
3222 @item @code{home-page}
3223 The URL to the home-page of the package, as a string.
3225 @item @code{supported-systems} (default: @var{%supported-systems})
3226 The list of systems supported by the package, as strings of the form
3227 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3229 @item @code{maintainers} (default: @code{'()})
3230 The list of maintainers of the package, as @code{maintainer} objects.
3232 @item @code{location} (default: source location of the @code{package} form)
3233 The source location of the package. It is useful to override this when
3234 inheriting from another package, in which case this field is not
3235 automatically corrected.
3240 @node origin Reference
3241 @subsection @code{origin} Reference
3243 This section summarizes all the options available in @code{origin}
3244 declarations (@pxref{Defining Packages}).
3246 @deftp {Data Type} origin
3247 This is the data type representing a source code origin.
3251 An object containing the URI of the source. The object type depends on
3252 the @code{method} (see below). For example, when using the
3253 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3254 values are: a URL represented as a string, or a list thereof.
3257 A procedure that handles the URI.
3262 @item @var{url-fetch} from @code{(guix download)}
3263 download a file from the HTTP, HTTPS, or FTP URL specified in the
3267 @item @var{git-fetch} from @code{(guix git-download)}
3268 clone the Git version control repository, and check out the revision
3269 specified in the @code{uri} field as a @code{git-reference} object; a
3270 @code{git-reference} looks like this:
3274 (url "git://git.debian.org/git/pkg-shadow/shadow")
3275 (commit "v4.1.5.1"))
3280 A bytevector containing the SHA-256 hash of the source. Typically the
3281 @code{base32} form is used here to generate the bytevector from a
3284 You can obtain this information using @code{guix download}
3285 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3288 @item @code{file-name} (default: @code{#f})
3289 The file name under which the source code should be saved. When this is
3290 @code{#f}, a sensible default value will be used in most cases. In case
3291 the source is fetched from a URL, the file name from the URL will be
3292 used. For version control checkouts, it is recommended to provide the
3293 file name explicitly because the default is not very descriptive.
3295 @item @code{patches} (default: @code{'()})
3296 A list of file names, origins, or file-like objects (@pxref{G-Expressions,
3297 file-like objects}) pointing to patches to be applied to the source.
3299 This list of patches must be unconditional. In particular, it cannot
3300 depend on the value of @code{%current-system} or
3301 @code{%current-target-system}.
3303 @item @code{snippet} (default: @code{#f})
3304 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3305 in the source directory. This is a convenient way to modify the source,
3306 sometimes more convenient than a patch.
3308 @item @code{patch-flags} (default: @code{'("-p1")})
3309 A list of command-line flags that should be passed to the @code{patch}
3312 @item @code{patch-inputs} (default: @code{#f})
3313 Input packages or derivations to the patching process. When this is
3314 @code{#f}, the usual set of inputs necessary for patching are provided,
3315 such as GNU@tie{}Patch.
3317 @item @code{modules} (default: @code{'()})
3318 A list of Guile modules that should be loaded during the patching
3319 process and while running the code in the @code{snippet} field.
3321 @item @code{patch-guile} (default: @code{#f})
3322 The Guile package that should be used in the patching process. When
3323 this is @code{#f}, a sensible default is used.
3329 @section Build Systems
3331 @cindex build system
3332 Each package definition specifies a @dfn{build system} and arguments for
3333 that build system (@pxref{Defining Packages}). This @code{build-system}
3334 field represents the build procedure of the package, as well as implicit
3335 dependencies of that build procedure.
3337 Build systems are @code{<build-system>} objects. The interface to
3338 create and manipulate them is provided by the @code{(guix build-system)}
3339 module, and actual build systems are exported by specific modules.
3341 @cindex bag (low-level package representation)
3342 Under the hood, build systems first compile package objects to
3343 @dfn{bags}. A @dfn{bag} is like a package, but with less
3344 ornamentation---in other words, a bag is a lower-level representation of
3345 a package, which includes all the inputs of that package, including some
3346 that were implicitly added by the build system. This intermediate
3347 representation is then compiled to a derivation (@pxref{Derivations}).
3349 Build systems accept an optional list of @dfn{arguments}. In package
3350 definitions, these are passed @i{via} the @code{arguments} field
3351 (@pxref{Defining Packages}). They are typically keyword arguments
3352 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3353 Guile Reference Manual}). The value of these arguments is usually
3354 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3355 by the daemon (@pxref{Derivations}).
3357 The main build system is @var{gnu-build-system}, which implements the
3358 standard build procedure for GNU and many other packages. It
3359 is provided by the @code{(guix build-system gnu)} module.
3361 @defvr {Scheme Variable} gnu-build-system
3362 @var{gnu-build-system} represents the GNU Build System, and variants
3363 thereof (@pxref{Configuration, configuration and makefile conventions,,
3364 standards, GNU Coding Standards}).
3366 @cindex build phases
3367 In a nutshell, packages using it are configured, built, and installed with
3368 the usual @code{./configure && make && make check && make install}
3369 command sequence. In practice, a few additional steps are often needed.
3370 All these steps are split up in separate @dfn{phases},
3371 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3372 modules for more details about the build phases.}:
3376 Unpack the source tarball, and change the current directory to the
3377 extracted source tree. If the source is actually a directory, copy it
3378 to the build tree, and enter that directory.
3380 @item patch-source-shebangs
3381 Patch shebangs encountered in source files so they refer to the right
3382 store file names. For instance, this changes @code{#!/bin/sh} to
3383 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3386 Run the @file{configure} script with a number of default options, such
3387 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3388 by the @code{#:configure-flags} argument.
3391 Run @code{make} with the list of flags specified with
3392 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3393 (the default), build with @code{make -j}.
3396 Run @code{make check}, or some other target specified with
3397 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3398 @code{#:parallel-tests?} argument is true (the default), run @code{make
3402 Run @code{make install} with the flags listed in @code{#:make-flags}.
3404 @item patch-shebangs
3405 Patch shebangs on the installed executable files.
3408 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3409 is false), copying them to the @code{debug} output when available
3410 (@pxref{Installing Debugging Files}).
3413 @vindex %standard-phases
3414 The build-side module @code{(guix build gnu-build-system)} defines
3415 @var{%standard-phases} as the default list of build phases.
3416 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3417 procedure implements the actual phase.
3419 The list of phases used for a particular package can be changed with the
3420 @code{#:phases} parameter. For instance, passing:
3423 #:phases (modify-phases %standard-phases (delete 'configure))
3426 means that all the phases described above will be used, except the
3427 @code{configure} phase.
3429 In addition, this build system ensures that the ``standard'' environment
3430 for GNU packages is available. This includes tools such as GCC, libc,
3431 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3432 build-system gnu)} module for a complete list). We call these the
3433 @dfn{implicit inputs} of a package, because package definitions do not
3434 have to mention them.
3437 Other @code{<build-system>} objects are defined to support other
3438 conventions and tools used by free software packages. They inherit most
3439 of @var{gnu-build-system}, and differ mainly in the set of inputs
3440 implicitly added to the build process, and in the list of phases
3441 executed. Some of these build systems are listed below.
3443 @defvr {Scheme Variable} ant-build-system
3444 This variable is exported by @code{(guix build-system ant)}. It
3445 implements the build procedure for Java packages that can be built with
3446 @url{http://ant.apache.org/, Ant build tool}.
3448 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3449 provided by the @code{icedtea} package to the set of inputs. Different
3450 packages can be specified with the @code{#:ant} and @code{#:jdk}
3451 parameters, respectively.
3453 When the original package does not provide a suitable Ant build file,
3454 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3455 build file @file{build.xml} with tasks to build the specified jar
3456 archive. In this case the parameter @code{#:source-dir} can be used to
3457 specify the source sub-directory, defaulting to ``src''.
3459 The parameter @code{#:build-target} can be used to specify the Ant task
3460 that should be run during the @code{build} phase. By default the
3461 ``jar'' task will be run.
3465 @defvr {Scheme Variable} asdf-build-system/source
3466 @defvrx {Scheme Variable} asdf-build-system/sbcl
3467 @defvrx {Scheme Variable} asdf-build-system/ecl
3469 These variables, exported by @code{(guix build-system asdf)}, implement
3470 build procedures for Common Lisp packages using
3471 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3472 definition facility for Common Lisp programs and libraries.
3474 The @code{asdf-build-system/source} system installs the packages in
3475 source form, and can be loaded using any common lisp implementation, via
3476 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3477 systems in the format which a particular implementation understands.
3478 These build systems can also be used to produce executable programs, or
3479 lisp images which contain a set of packages pre-loaded.
3481 The build system uses naming conventions. For binary packages, the
3482 package name should be prefixed with the lisp implementation, such as
3483 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3485 Additionally, the corresponding source package should be labeled using
3486 the same convention as python packages (see @ref{Python Modules}), using
3487 the @code{cl-} prefix.
3489 For binary packages, each system should be defined as a Guix package.
3490 If one package @code{origin} contains several systems, package variants
3491 can be created in order to build all the systems. Source packages,
3492 which use @code{asdf-build-system/source}, may contain several systems.
3494 In order to create executable programs and images, the build-side
3495 procedures @code{build-program} and @code{build-image} can be used.
3496 They should be called in a build phase after the @code{create-symlinks}
3497 phase, so that the system which was just built can be used within the
3498 resulting image. @code{build-program} requires a list of Common Lisp
3499 expressions to be passed as the @code{#:entry-program} argument.
3501 If the system is not defined within its own @code{.asd} file of the same
3502 name, then the @code{#:asd-file} parameter should be used to specify
3503 which file the system is defined in. Furthermore, if the package
3504 defines a system for its tests in a separate file, it will be loaded
3505 before the tests are run if it is specified by the
3506 @code{#:test-asd-file} parameter. If it is not set, the files
3507 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3508 and @code{test.asd} will be tried if they exist.
3510 If for some reason the package must be named in a different way than the
3511 naming conventions suggest, the @code{#:asd-system-name} parameter can
3512 be used to specify the name of the system.
3516 @defvr {Scheme Variable} cargo-build-system
3517 @cindex Rust programming language
3518 @cindex Cargo (Rust build system)
3519 This variable is exported by @code{(guix build-system cargo)}. It
3520 supports builds of packages using Cargo, the build tool of the
3521 @uref{https://www.rust-lang.org, Rust programming language}.
3523 In its @code{configure} phase, this build system replaces dependencies
3524 specified in the @file{Carto.toml} file with inputs to the Guix package.
3525 The @code{install} phase installs the binaries, and it also installs the
3526 source code and @file{Cargo.toml} file.
3529 @defvr {Scheme Variable} cmake-build-system
3530 This variable is exported by @code{(guix build-system cmake)}. It
3531 implements the build procedure for packages using the
3532 @url{http://www.cmake.org, CMake build tool}.
3534 It automatically adds the @code{cmake} package to the set of inputs.
3535 Which package is used can be specified with the @code{#:cmake}
3538 The @code{#:configure-flags} parameter is taken as a list of flags
3539 passed to the @command{cmake} command. The @code{#:build-type}
3540 parameter specifies in abstract terms the flags passed to the compiler;
3541 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3542 debugging information''), which roughly means that code is compiled with
3543 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3546 @defvr {Scheme Variable} glib-or-gtk-build-system
3547 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3548 is intended for use with packages making use of GLib or GTK+.
3550 This build system adds the following two phases to the ones defined by
3551 @var{gnu-build-system}:
3554 @item glib-or-gtk-wrap
3555 The phase @code{glib-or-gtk-wrap} ensures that programs in
3556 @file{bin/} are able to find GLib ``schemas'' and
3557 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3558 modules}. This is achieved by wrapping the programs in launch scripts
3559 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3560 environment variables.
3562 It is possible to exclude specific package outputs from that wrapping
3563 process by listing their names in the
3564 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3565 when an output is known not to contain any GLib or GTK+ binaries, and
3566 where wrapping would gratuitously add a dependency of that output on
3569 @item glib-or-gtk-compile-schemas
3570 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3571 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3572 GSettings schemas} of GLib are compiled. Compilation is performed by the
3573 @command{glib-compile-schemas} program. It is provided by the package
3574 @code{glib:bin} which is automatically imported by the build system.
3575 The @code{glib} package providing @command{glib-compile-schemas} can be
3576 specified with the @code{#:glib} parameter.
3579 Both phases are executed after the @code{install} phase.
3582 @defvr {Scheme Variable} minify-build-system
3583 This variable is exported by @code{(guix build-system minify)}. It
3584 implements a minification procedure for simple JavaScript packages.
3586 It adds @code{uglify-js} to the set of inputs and uses it to compress
3587 all JavaScript files in the @file{src} directory. A different minifier
3588 package can be specified with the @code{#:uglify-js} parameter, but it
3589 is expected that the package writes the minified code to the standard
3592 When the input JavaScript files are not all located in the @file{src}
3593 directory, the parameter @code{#:javascript-files} can be used to
3594 specify a list of file names to feed to the minifier.
3597 @defvr {Scheme Variable} ocaml-build-system
3598 This variable is exported by @code{(guix build-system ocaml)}. It implements
3599 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3600 of choosing the correct set of commands to run for each package. OCaml
3601 packages can expect many different commands to be run. This build system will
3604 When the package has a @file{setup.ml} file present at the top-level, it will
3605 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3606 @code{ocaml setup.ml -install}. The build system will assume that this file
3607 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3608 care of setting the prefix and enabling tests if they are not disabled. You
3609 can pass configure and build flags with the @code{#:configure-flags} and
3610 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3611 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3612 bypass this system in the build and install phases.
3614 When the package has a @file{configure} file, it is assumed that it is a
3615 hand-made configure script that requires a different argument format than
3616 in the @code{gnu-build-system}. You can add more flags with the
3617 @code{#:configure-flags} key.
3619 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3620 @code{#t}), it will be used and more flags can be passed to the build and
3621 install phases with the @code{#:make-flags} key.
3623 Finally, some packages do not have these files and use a somewhat standard
3624 location for its build system. In that case, the build system will run
3625 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3626 providing the path to the required findlib module. Additional flags can
3627 be passed via the @code{#:build-flags} key. Install is taken care of by
3628 @command{opam-installer}. In this case, the @code{opam} package must
3629 be added to the @code{native-inputs} field of the package definition.
3631 Note that most OCaml packages assume they will be installed in the same
3632 directory as OCaml, which is not what we want in guix. In particular, they
3633 will install @file{.so} files in their module's directory, which is usually
3634 fine because it is in the OCaml compiler directory. In guix though, these
3635 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3636 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3637 @file{.so} libraries should be installed.
3640 @defvr {Scheme Variable} python-build-system
3641 This variable is exported by @code{(guix build-system python)}. It
3642 implements the more or less standard build procedure used by Python
3643 packages, which consists in running @code{python setup.py build} and
3644 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3646 For packages that install stand-alone Python programs under @code{bin/},
3647 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3648 environment variable points to all the Python libraries they depend on.
3650 Which Python package is used to perform the build can be specified with
3651 the @code{#:python} parameter. This is a useful way to force a package
3652 to be built for a specific version of the Python interpreter, which
3653 might be necessary if the package is only compatible with a single
3654 interpreter version.
3656 By default guix calls @code{setup.py} under control of
3657 @code{setuptools}, much like @command{pip} does. Some packages are not
3658 compatible with setuptools (and pip), thus you can disable this by
3659 setting the @code{#:use-setuptools} parameter to @code{#f}.
3662 @defvr {Scheme Variable} perl-build-system
3663 This variable is exported by @code{(guix build-system perl)}. It
3664 implements the standard build procedure for Perl packages, which either
3665 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3666 followed by @code{Build} and @code{Build install}; or in running
3667 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3668 @code{make} and @code{make install}, depending on which of
3669 @code{Build.PL} or @code{Makefile.PL} is present in the package
3670 distribution. Preference is given to the former if both @code{Build.PL}
3671 and @code{Makefile.PL} exist in the package distribution. This
3672 preference can be reversed by specifying @code{#t} for the
3673 @code{#:make-maker?} parameter.
3675 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3676 passes flags specified by the @code{#:make-maker-flags} or
3677 @code{#:module-build-flags} parameter, respectively.
3679 Which Perl package is used can be specified with @code{#:perl}.
3682 @defvr {Scheme Variable} r-build-system
3683 This variable is exported by @code{(guix build-system r)}. It
3684 implements the build procedure used by @uref{http://r-project.org, R}
3685 packages, which essentially is little more than running @code{R CMD
3686 INSTALL --library=/gnu/store/@dots{}} in an environment where
3687 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3688 are run after installation using the R function
3689 @code{tools::testInstalledPackage}.
3692 @defvr {Scheme Variable} texlive-build-system
3693 This variable is exported by @code{(guix build-system texlive)}. It is
3694 used to build TeX packages in batch mode with a specified engine. The
3695 build system sets the @code{TEXINPUTS} variable to find all TeX source
3696 files in the inputs.
3698 By default it runs @code{luatex} on all files ending on @code{ins}. A
3699 different engine and format can be specified with the
3700 @code{#:tex-format} argument. Different build targets can be specified
3701 with the @code{#:build-targets} argument, which expects a list of file
3702 names. The build system adds only @code{texlive-bin} and
3703 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3704 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3705 and @code{#:texlive-latex-base}, respectively.
3707 The @code{#:tex-directory} parameter tells the build system where to
3708 install the built files under the texmf tree.
3711 @defvr {Scheme Variable} ruby-build-system
3712 This variable is exported by @code{(guix build-system ruby)}. It
3713 implements the RubyGems build procedure used by Ruby packages, which
3714 involves running @code{gem build} followed by @code{gem install}.
3716 The @code{source} field of a package that uses this build system
3717 typically references a gem archive, since this is the format that Ruby
3718 developers use when releasing their software. The build system unpacks
3719 the gem archive, potentially patches the source, runs the test suite,
3720 repackages the gem, and installs it. Additionally, directories and
3721 tarballs may be referenced to allow building unreleased gems from Git or
3722 a traditional source release tarball.
3724 Which Ruby package is used can be specified with the @code{#:ruby}
3725 parameter. A list of additional flags to be passed to the @command{gem}
3726 command can be specified with the @code{#:gem-flags} parameter.
3729 @defvr {Scheme Variable} waf-build-system
3730 This variable is exported by @code{(guix build-system waf)}. It
3731 implements a build procedure around the @code{waf} script. The common
3732 phases---@code{configure}, @code{build}, and @code{install}---are
3733 implemented by passing their names as arguments to the @code{waf}
3736 The @code{waf} script is executed by the Python interpreter. Which
3737 Python package is used to run the script can be specified with the
3738 @code{#:python} parameter.
3741 @defvr {Scheme Variable} haskell-build-system
3742 This variable is exported by @code{(guix build-system haskell)}. It
3743 implements the Cabal build procedure used by Haskell packages, which
3744 involves running @code{runhaskell Setup.hs configure
3745 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3746 Instead of installing the package by running @code{runhaskell Setup.hs
3747 install}, to avoid trying to register libraries in the read-only
3748 compiler store directory, the build system uses @code{runhaskell
3749 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3750 addition, the build system generates the package documentation by
3751 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3752 is passed. Optional Haddock parameters can be passed with the help of
3753 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3754 not found, the build system looks for @code{Setup.lhs} instead.
3756 Which Haskell compiler is used can be specified with the @code{#:haskell}
3757 parameter which defaults to @code{ghc}.
3760 @defvr {Scheme Variable} dub-build-system
3761 This variable is exported by @code{(guix build-system dub)}. It
3762 implements the Dub build procedure used by D packages, which
3763 involves running @code{dub build} and @code{dub run}.
3764 Installation is done by copying the files manually.
3766 Which D compiler is used can be specified with the @code{#:ldc}
3767 parameter which defaults to @code{ldc}.
3770 @defvr {Scheme Variable} emacs-build-system
3771 This variable is exported by @code{(guix build-system emacs)}. It
3772 implements an installation procedure similar to the packaging system
3773 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3775 It first creates the @code{@var{package}-autoloads.el} file, then it
3776 byte compiles all Emacs Lisp files. Differently from the Emacs
3777 packaging system, the Info documentation files are moved to the standard
3778 documentation directory and the @file{dir} file is deleted. Each
3779 package is installed in its own directory under
3780 @file{share/emacs/site-lisp/guix.d}.
3783 @defvr {Scheme Variable} font-build-system
3784 This variable is exported by @code{(guix build-system font)}. It
3785 implements an installation procedure for font packages where upstream
3786 provides pre-compiled TrueType, OpenType, etc. font files that merely
3787 need to be copied into place. It copies font files to standard
3788 locations in the output directory.
3791 Lastly, for packages that do not need anything as sophisticated, a
3792 ``trivial'' build system is provided. It is trivial in the sense that
3793 it provides basically no support: it does not pull any implicit inputs,
3794 and does not have a notion of build phases.
3796 @defvr {Scheme Variable} trivial-build-system
3797 This variable is exported by @code{(guix build-system trivial)}.
3799 This build system requires a @code{#:builder} argument. This argument
3800 must be a Scheme expression that builds the package output(s)---as
3801 with @code{build-expression->derivation} (@pxref{Derivations,
3802 @code{build-expression->derivation}}).
3812 Conceptually, the @dfn{store} is the place where derivations that have
3813 been built successfully are stored---by default, @file{/gnu/store}.
3814 Sub-directories in the store are referred to as @dfn{store items} or
3815 sometimes @dfn{store paths}. The store has an associated database that
3816 contains information such as the store paths referred to by each store
3817 path, and the list of @emph{valid} store items---results of successful
3818 builds. This database resides in @file{@var{localstatedir}/guix/db},
3819 where @var{localstatedir} is the state directory specified @i{via}
3820 @option{--localstatedir} at configure time, usually @file{/var}.
3822 The store is @emph{always} accessed by the daemon on behalf of its clients
3823 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3824 connect to the daemon over a Unix-domain socket, send requests to it,
3825 and read the result---these are remote procedure calls, or RPCs.
3828 Users must @emph{never} modify files under @file{/gnu/store} directly.
3829 This would lead to inconsistencies and break the immutability
3830 assumptions of Guix's functional model (@pxref{Introduction}).
3832 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3833 how to check the integrity of the store and attempt recovery from
3834 accidental modifications.
3837 The @code{(guix store)} module provides procedures to connect to the
3838 daemon, and to perform RPCs. These are described below. By default,
3839 @code{open-connection}, and thus all the @command{guix} commands,
3840 connect to the local daemon or to the URI specified by the
3841 @code{GUIX_DAEMON_SOCKET} environment variable.
3843 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3844 When set, the value of this variable should be a file name or a URI
3845 designating the daemon endpoint. When it is a file name, it denotes a
3846 Unix-domain socket to connect to. In addition to file names, the
3847 supported URI schemes are:
3852 These are for Unix-domain sockets.
3853 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3854 @file{/var/guix/daemon-socket/socket}.
3857 @cindex daemon, remote access
3858 @cindex remote access to the daemon
3859 @cindex daemon, cluster setup
3860 @cindex clusters, daemon setup
3861 These URIs denote connections over TCP/IP, without encryption nor
3862 authentication of the remote host. The URI must specify the host name
3863 and optionally a port number (by default port 44146 is used):
3866 guix://master.guix.example.org:1234
3869 This setup is suitable on local networks, such as clusters, where only
3870 trusted nodes may connect to the build daemon at
3871 @code{master.guix.example.org}.
3873 The @code{--listen} option of @command{guix-daemon} can be used to
3874 instruct it to listen for TCP connections (@pxref{Invoking guix-daemon,
3878 @cindex SSH access to build daemons
3879 These URIs allow you to connect to a remote daemon over
3880 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3881 A typical URL might look like this:
3884 ssh://charlie@@guix.example.org:22
3887 As for @command{guix copy}, the usual OpenSSH client configuration files
3888 are honored (@pxref{Invoking guix copy}).
3891 Additional URI schemes may be supported in the future.
3893 @c XXX: Remove this note when the protocol incurs fewer round trips
3894 @c and when (guix derivations) no longer relies on file system access.
3896 The ability to connect to remote build daemons is considered
3897 experimental as of @value{VERSION}. Please get in touch with us to
3898 share any problems or suggestions you may have (@pxref{Contributing}).
3902 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3903 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3904 @var{reserve-space?} is true, instruct it to reserve a little bit of
3905 extra space on the file system so that the garbage collector can still
3906 operate should the disk become full. Return a server object.
3908 @var{file} defaults to @var{%default-socket-path}, which is the normal
3909 location given the options that were passed to @command{configure}.
3912 @deffn {Scheme Procedure} close-connection @var{server}
3913 Close the connection to @var{server}.
3916 @defvr {Scheme Variable} current-build-output-port
3917 This variable is bound to a SRFI-39 parameter, which refers to the port
3918 where build and error logs sent by the daemon should be written.
3921 Procedures that make RPCs all take a server object as their first
3924 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3925 @cindex invalid store items
3926 Return @code{#t} when @var{path} designates a valid store item and
3927 @code{#f} otherwise (an invalid item may exist on disk but still be
3928 invalid, for instance because it is the result of an aborted or failed
3931 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3932 prefixed by the store directory (@file{/gnu/store}).
3935 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3936 Add @var{text} under file @var{name} in the store, and return its store
3937 path. @var{references} is the list of store paths referred to by the
3938 resulting store path.
3941 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3942 Build @var{derivations} (a list of @code{<derivation>} objects or
3943 derivation paths), and return when the worker is done building them.
3944 Return @code{#t} on success.
3947 Note that the @code{(guix monads)} module provides a monad as well as
3948 monadic versions of the above procedures, with the goal of making it
3949 more convenient to work with code that accesses the store (@pxref{The
3953 @i{This section is currently incomplete.}
3956 @section Derivations
3959 Low-level build actions and the environment in which they are performed
3960 are represented by @dfn{derivations}. A derivation contains the
3961 following pieces of information:
3965 The outputs of the derivation---derivations produce at least one file or
3966 directory in the store, but may produce more.
3969 The inputs of the derivations, which may be other derivations or plain
3970 files in the store (patches, build scripts, etc.)
3973 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3976 The file name of a build script in the store, along with the arguments
3980 A list of environment variables to be defined.
3984 @cindex derivation path
3985 Derivations allow clients of the daemon to communicate build actions to
3986 the store. They exist in two forms: as an in-memory representation,
3987 both on the client- and daemon-side, and as files in the store whose
3988 name end in @code{.drv}---these files are referred to as @dfn{derivation
3989 paths}. Derivations paths can be passed to the @code{build-derivations}
3990 procedure to perform the build actions they prescribe (@pxref{The
3993 The @code{(guix derivations)} module provides a representation of
3994 derivations as Scheme objects, along with procedures to create and
3995 otherwise manipulate derivations. The lowest-level primitive to create
3996 a derivation is the @code{derivation} procedure:
3998 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3999 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4000 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
4001 [#:system (%current-system)] [#:references-graphs #f] @
4002 [#:allowed-references #f] [#:disallowed-references #f] @
4003 [#:leaked-env-vars #f] [#:local-build? #f] @
4004 [#:substitutable? #t]
4005 Build a derivation with the given arguments, and return the resulting
4006 @code{<derivation>} object.
4008 When @var{hash} and @var{hash-algo} are given, a
4009 @dfn{fixed-output derivation} is created---i.e., one whose result is
4010 known in advance, such as a file download. If, in addition,
4011 @var{recursive?} is true, then that fixed output may be an executable
4012 file or a directory and @var{hash} must be the hash of an archive
4013 containing this output.
4015 When @var{references-graphs} is true, it must be a list of file
4016 name/store path pairs. In that case, the reference graph of each store
4017 path is exported in the build environment in the corresponding file, in
4018 a simple text format.
4020 When @var{allowed-references} is true, it must be a list of store items
4021 or outputs that the derivation's output may refer to. Likewise,
4022 @var{disallowed-references}, if true, must be a list of things the
4023 outputs may @emph{not} refer to.
4025 When @var{leaked-env-vars} is true, it must be a list of strings
4026 denoting environment variables that are allowed to ``leak'' from the
4027 daemon's environment to the build environment. This is only applicable
4028 to fixed-output derivations---i.e., when @var{hash} is true. The main
4029 use is to allow variables such as @code{http_proxy} to be passed to
4030 derivations that download files.
4032 When @var{local-build?} is true, declare that the derivation is not a
4033 good candidate for offloading and should rather be built locally
4034 (@pxref{Daemon Offload Setup}). This is the case for small derivations
4035 where the costs of data transfers would outweigh the benefits.
4037 When @var{substitutable?} is false, declare that substitutes of the
4038 derivation's output should not be used (@pxref{Substitutes}). This is
4039 useful, for instance, when building packages that capture details of the
4040 host CPU instruction set.
4044 Here's an example with a shell script as its builder, assuming
4045 @var{store} is an open connection to the daemon, and @var{bash} points
4046 to a Bash executable in the store:
4049 (use-modules (guix utils)
4053 (let ((builder ; add the Bash script to the store
4054 (add-text-to-store store "my-builder.sh"
4055 "echo hello world > $out\n" '())))
4056 (derivation store "foo"
4057 bash `("-e" ,builder)
4058 #:inputs `((,bash) (,builder))
4059 #:env-vars '(("HOME" . "/homeless"))))
4060 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
4063 As can be guessed, this primitive is cumbersome to use directly. A
4064 better approach is to write build scripts in Scheme, of course! The
4065 best course of action for that is to write the build code as a
4066 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
4067 information, @pxref{G-Expressions}.
4069 Once upon a time, @code{gexp->derivation} did not exist and constructing
4070 derivations with build code written in Scheme was achieved with
4071 @code{build-expression->derivation}, documented below. This procedure
4072 is now deprecated in favor of the much nicer @code{gexp->derivation}.
4074 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
4075 @var{name} @var{exp} @
4076 [#:system (%current-system)] [#:inputs '()] @
4077 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4078 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4079 [#:references-graphs #f] [#:allowed-references #f] @
4080 [#:disallowed-references #f] @
4081 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4082 Return a derivation that executes Scheme expression @var{exp} as a
4083 builder for derivation @var{name}. @var{inputs} must be a list of
4084 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
4085 @code{"out"} is assumed. @var{modules} is a list of names of Guile
4086 modules from the current search path to be copied in the store,
4087 compiled, and made available in the load path during the execution of
4088 @var{exp}---e.g., @code{((guix build utils) (guix build
4089 gnu-build-system))}.
4091 @var{exp} is evaluated in an environment where @code{%outputs} is bound
4092 to a list of output/path pairs, and where @code{%build-inputs} is bound
4093 to a list of string/output-path pairs made from @var{inputs}.
4094 Optionally, @var{env-vars} is a list of string pairs specifying the name
4095 and value of environment variables visible to the builder. The builder
4096 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4097 @var{exp} returns @code{#f}, the build is considered to have failed.
4099 @var{exp} is built using @var{guile-for-build} (a derivation). When
4100 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4101 @code{%guile-for-build} fluid is used instead.
4103 See the @code{derivation} procedure for the meaning of
4104 @var{references-graphs}, @var{allowed-references},
4105 @var{disallowed-references}, @var{local-build?}, and
4106 @var{substitutable?}.
4110 Here's an example of a single-output derivation that creates a directory
4111 containing one file:
4114 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4115 (mkdir out) ; create /gnu/store/@dots{}-goo
4116 (call-with-output-file (string-append out "/test")
4118 (display '(hello guix) p))))))
4119 (build-expression->derivation store "goo" builder))
4121 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4125 @node The Store Monad
4126 @section The Store Monad
4130 The procedures that operate on the store described in the previous
4131 sections all take an open connection to the build daemon as their first
4132 argument. Although the underlying model is functional, they either have
4133 side effects or depend on the current state of the store.
4135 The former is inconvenient: the connection to the build daemon has to be
4136 carried around in all those functions, making it impossible to compose
4137 functions that do not take that parameter with functions that do. The
4138 latter can be problematic: since store operations have side effects
4139 and/or depend on external state, they have to be properly sequenced.
4141 @cindex monadic values
4142 @cindex monadic functions
4143 This is where the @code{(guix monads)} module comes in. This module
4144 provides a framework for working with @dfn{monads}, and a particularly
4145 useful monad for our uses, the @dfn{store monad}. Monads are a
4146 construct that allows two things: associating ``context'' with values
4147 (in our case, the context is the store), and building sequences of
4148 computations (here computations include accesses to the store). Values
4149 in a monad---values that carry this additional context---are called
4150 @dfn{monadic values}; procedures that return such values are called
4151 @dfn{monadic procedures}.
4153 Consider this ``normal'' procedure:
4156 (define (sh-symlink store)
4157 ;; Return a derivation that symlinks the 'bash' executable.
4158 (let* ((drv (package-derivation store bash))
4159 (out (derivation->output-path drv))
4160 (sh (string-append out "/bin/bash")))
4161 (build-expression->derivation store "sh"
4162 `(symlink ,sh %output))))
4165 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4166 as a monadic function:
4169 (define (sh-symlink)
4170 ;; Same, but return a monadic value.
4171 (mlet %store-monad ((drv (package->derivation bash)))
4172 (gexp->derivation "sh"
4173 #~(symlink (string-append #$drv "/bin/bash")
4177 There are several things to note in the second version: the @code{store}
4178 parameter is now implicit and is ``threaded'' in the calls to the
4179 @code{package->derivation} and @code{gexp->derivation} monadic
4180 procedures, and the monadic value returned by @code{package->derivation}
4181 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4183 As it turns out, the call to @code{package->derivation} can even be
4184 omitted since it will take place implicitly, as we will see later
4185 (@pxref{G-Expressions}):
4188 (define (sh-symlink)
4189 (gexp->derivation "sh"
4190 #~(symlink (string-append #$bash "/bin/bash")
4195 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4196 @c for the funny quote.
4197 Calling the monadic @code{sh-symlink} has no effect. As someone once
4198 said, ``you exit a monad like you exit a building on fire: by running''.
4199 So, to exit the monad and get the desired effect, one must use
4200 @code{run-with-store}:
4203 (run-with-store (open-connection) (sh-symlink))
4204 @result{} /gnu/store/...-sh-symlink
4207 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4208 new ``meta-commands'' to make it easier to deal with monadic procedures:
4209 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4210 to ``run'' a single monadic value through the store:
4213 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4214 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4217 The latter enters a recursive REPL, where all the return values are
4218 automatically run through the store:
4221 scheme@@(guile-user)> ,enter-store-monad
4222 store-monad@@(guile-user) [1]> (package->derivation hello)
4223 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4224 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4225 $3 = "/gnu/store/@dots{}-foo"
4226 store-monad@@(guile-user) [1]> ,q
4227 scheme@@(guile-user)>
4231 Note that non-monadic values cannot be returned in the
4232 @code{store-monad} REPL.
4234 The main syntactic forms to deal with monads in general are provided by
4235 the @code{(guix monads)} module and are described below.
4237 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4238 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4242 @deffn {Scheme Syntax} return @var{val}
4243 Return a monadic value that encapsulates @var{val}.
4246 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4247 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4248 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4249 referred to as ``bind'', but that name denotes an unrelated procedure in
4250 Guile. Thus we use this somewhat cryptic symbol inherited from the
4251 Haskell language.}. There can be one @var{mproc} or several of them, as
4256 (with-monad %state-monad
4258 (lambda (x) (return (+ 1 x)))
4259 (lambda (x) (return (* 2 x)))))
4263 @result{} some-state
4267 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4269 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4271 Bind the variables @var{var} to the monadic values @var{mval} in
4272 @var{body}, which is a sequence of expressions. As with the bind
4273 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4274 value ``contained'' in @var{mval} and making @var{var} refer to that
4275 raw, non-monadic value within the scope of the @var{body}. The form
4276 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4277 @var{val}, as per @code{let}. The binding operations occur in sequence
4278 from left to right. The last expression of @var{body} must be a monadic
4279 expression, and its result will become the result of the @code{mlet} or
4280 @code{mlet*} when run in the @var{monad}.
4282 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4283 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4286 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4287 Bind @var{mexp} and the following monadic expressions in sequence,
4288 returning the result of the last expression. Every expression in the
4289 sequence must be a monadic expression.
4291 This is akin to @code{mlet}, except that the return values of the
4292 monadic expressions are ignored. In that sense, it is analogous to
4293 @code{begin}, but applied to monadic expressions.
4296 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4297 When @var{condition} is true, evaluate the sequence of monadic
4298 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4299 @var{condition} is false, return @code{*unspecified*} in the current
4300 monad. Every expression in the sequence must be a monadic expression.
4303 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4304 When @var{condition} is false, evaluate the sequence of monadic
4305 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4306 @var{condition} is true, return @code{*unspecified*} in the current
4307 monad. Every expression in the sequence must be a monadic expression.
4311 The @code{(guix monads)} module provides the @dfn{state monad}, which
4312 allows an additional value---the state---to be @emph{threaded} through
4313 monadic procedure calls.
4315 @defvr {Scheme Variable} %state-monad
4316 The state monad. Procedures in the state monad can access and change
4317 the state that is threaded.
4319 Consider the example below. The @code{square} procedure returns a value
4320 in the state monad. It returns the square of its argument, but also
4321 increments the current state value:
4325 (mlet %state-monad ((count (current-state)))
4326 (mbegin %state-monad
4327 (set-current-state (+ 1 count))
4330 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4335 When ``run'' through @var{%state-monad}, we obtain that additional state
4336 value, which is the number of @code{square} calls.
4339 @deffn {Monadic Procedure} current-state
4340 Return the current state as a monadic value.
4343 @deffn {Monadic Procedure} set-current-state @var{value}
4344 Set the current state to @var{value} and return the previous state as a
4348 @deffn {Monadic Procedure} state-push @var{value}
4349 Push @var{value} to the current state, which is assumed to be a list,
4350 and return the previous state as a monadic value.
4353 @deffn {Monadic Procedure} state-pop
4354 Pop a value from the current state and return it as a monadic value.
4355 The state is assumed to be a list.
4358 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4359 Run monadic value @var{mval} starting with @var{state} as the initial
4360 state. Return two values: the resulting value, and the resulting state.
4363 The main interface to the store monad, provided by the @code{(guix
4364 store)} module, is as follows.
4366 @defvr {Scheme Variable} %store-monad
4367 The store monad---an alias for @var{%state-monad}.
4369 Values in the store monad encapsulate accesses to the store. When its
4370 effect is needed, a value of the store monad must be ``evaluated'' by
4371 passing it to the @code{run-with-store} procedure (see below.)
4374 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4375 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4376 open store connection.
4379 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4380 Return as a monadic value the absolute file name in the store of the file
4381 containing @var{text}, a string. @var{references} is a list of store items that the
4382 resulting text file refers to; it defaults to the empty list.
4385 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4386 [#:recursive? #t] [#:select? (const #t)]
4387 Return the name of @var{file} once interned in the store. Use
4388 @var{name} as its store name, or the basename of @var{file} if
4389 @var{name} is omitted.
4391 When @var{recursive?} is true, the contents of @var{file} are added
4392 recursively; if @var{file} designates a flat file and @var{recursive?}
4393 is true, its contents are added, and its permission bits are kept.
4395 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4396 @var{stat})} for each directory entry, where @var{file} is the entry's
4397 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4398 entries for which @var{select?} does not return true.
4400 The example below adds a file to the store, under two different names:
4403 (run-with-store (open-connection)
4404 (mlet %store-monad ((a (interned-file "README"))
4405 (b (interned-file "README" "LEGU-MIN")))
4406 (return (list a b))))
4408 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4413 The @code{(guix packages)} module exports the following package-related
4416 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4417 [#:system (%current-system)] [#:target #f] @
4420 value in the absolute file name of @var{file} within the @var{output}
4421 directory of @var{package}. When @var{file} is omitted, return the name
4422 of the @var{output} directory of @var{package}. When @var{target} is
4423 true, use it as a cross-compilation target triplet.
4426 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4427 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4428 @var{target} [@var{system}]
4429 Monadic version of @code{package-derivation} and
4430 @code{package-cross-derivation} (@pxref{Defining Packages}).
4435 @section G-Expressions
4437 @cindex G-expression
4438 @cindex build code quoting
4439 So we have ``derivations'', which represent a sequence of build actions
4440 to be performed to produce an item in the store (@pxref{Derivations}).
4441 These build actions are performed when asking the daemon to actually
4442 build the derivations; they are run by the daemon in a container
4443 (@pxref{Invoking guix-daemon}).
4445 @cindex strata of code
4446 It should come as no surprise that we like to write these build actions
4447 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4448 code@footnote{The term @dfn{stratum} in this context was coined by
4449 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4450 Kiselyov, who has written insightful
4451 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4452 on this topic}, refers to this kind of code generation as
4453 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4454 to the daemon, etc.---and the ``build code''---code that actually
4455 performs build actions, such as making directories, invoking
4456 @command{make}, etc.
4458 To describe a derivation and its build actions, one typically needs to
4459 embed build code inside host code. It boils down to manipulating build
4460 code as data, and the homoiconicity of Scheme---code has a direct
4461 representation as data---comes in handy for that. But we need more than
4462 the normal @code{quasiquote} mechanism in Scheme to construct build
4465 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4466 S-expressions adapted to build expressions. G-expressions, or
4467 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4468 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4469 @code{#$}, and @code{#$@@}), which are comparable to
4470 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4471 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4472 GNU Guile Reference Manual}). However, there are major differences:
4476 Gexps are meant to be written to a file and run or manipulated by other
4480 When a high-level object such as a package or derivation is unquoted
4481 inside a gexp, the result is as if its output file name had been
4485 Gexps carry information about the packages or derivations they refer to,
4486 and these dependencies are automatically added as inputs to the build
4487 processes that use them.
4490 @cindex lowering, of high-level objects in gexps
4491 This mechanism is not limited to package and derivation
4492 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4493 derivations or files in the store can be defined,
4494 such that these objects can also be inserted
4495 into gexps. For example, a useful type of high-level objects that can be
4496 inserted in a gexp is ``file-like objects'', which make it easy to
4497 add files to the store and to refer to them in
4498 derivations and such (see @code{local-file} and @code{plain-file}
4501 To illustrate the idea, here is an example of a gexp:
4508 (symlink (string-append #$coreutils "/bin/ls")
4512 This gexp can be passed to @code{gexp->derivation}; we obtain a
4513 derivation that builds a directory containing exactly one symlink to
4514 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4517 (gexp->derivation "the-thing" build-exp)
4520 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4521 substituted to the reference to the @var{coreutils} package in the
4522 actual build code, and @var{coreutils} is automatically made an input to
4523 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4524 output)}) is replaced by a string containing the directory name of the
4525 output of the derivation.
4527 @cindex cross compilation
4528 In a cross-compilation context, it is useful to distinguish between
4529 references to the @emph{native} build of a package---that can run on the
4530 host---versus references to cross builds of a package. To that end, the
4531 @code{#+} plays the same role as @code{#$}, but is a reference to a
4532 native package build:
4535 (gexp->derivation "vi"
4538 (system* (string-append #+coreutils "/bin/ln")
4540 (string-append #$emacs "/bin/emacs")
4541 (string-append #$output "/bin/vi")))
4542 #:target "mips64el-linux-gnu")
4546 In the example above, the native build of @var{coreutils} is used, so
4547 that @command{ln} can actually run on the host; but then the
4548 cross-compiled build of @var{emacs} is referenced.
4550 @cindex imported modules, for gexps
4551 @findex with-imported-modules
4552 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4553 able to use certain Guile modules from the ``host environment'' in the
4554 gexp, so those modules should be imported in the ``build environment''.
4555 The @code{with-imported-modules} form allows you to express that:
4558 (let ((build (with-imported-modules '((guix build utils))
4560 (use-modules (guix build utils))
4561 (mkdir-p (string-append #$output "/bin"))))))
4562 (gexp->derivation "empty-dir"
4565 (display "success!\n")
4570 In this example, the @code{(guix build utils)} module is automatically
4571 pulled into the isolated build environment of our gexp, such that
4572 @code{(use-modules (guix build utils))} works as expected.
4574 @cindex module closure
4575 @findex source-module-closure
4576 Usually you want the @emph{closure} of the module to be imported---i.e.,
4577 the module itself and all the modules it depends on---rather than just
4578 the module; failing to do that, attempts to use the module will fail
4579 because of missing dependent modules. The @code{source-module-closure}
4580 procedure computes the closure of a module by looking at its source file
4581 headers, which comes in handy in this case:
4584 (use-modules (guix modules)) ;for 'source-module-closure'
4586 (with-imported-modules (source-module-closure
4587 '((guix build utils)
4589 (gexp->derivation "something-with-vms"
4591 (use-modules (guix build utils)
4596 The syntactic form to construct gexps is summarized below.
4598 @deffn {Scheme Syntax} #~@var{exp}
4599 @deffnx {Scheme Syntax} (gexp @var{exp})
4600 Return a G-expression containing @var{exp}. @var{exp} may contain one
4601 or more of the following forms:
4605 @itemx (ungexp @var{obj})
4606 Introduce a reference to @var{obj}. @var{obj} may have one of the
4607 supported types, for example a package or a
4608 derivation, in which case the @code{ungexp} form is replaced by its
4609 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4611 If @var{obj} is a list, it is traversed and references to supported
4612 objects are substituted similarly.
4614 If @var{obj} is another gexp, its contents are inserted and its
4615 dependencies are added to those of the containing gexp.
4617 If @var{obj} is another kind of object, it is inserted as is.
4619 @item #$@var{obj}:@var{output}
4620 @itemx (ungexp @var{obj} @var{output})
4621 This is like the form above, but referring explicitly to the
4622 @var{output} of @var{obj}---this is useful when @var{obj} produces
4623 multiple outputs (@pxref{Packages with Multiple Outputs}).
4626 @itemx #+@var{obj}:output
4627 @itemx (ungexp-native @var{obj})
4628 @itemx (ungexp-native @var{obj} @var{output})
4629 Same as @code{ungexp}, but produces a reference to the @emph{native}
4630 build of @var{obj} when used in a cross compilation context.
4632 @item #$output[:@var{output}]
4633 @itemx (ungexp output [@var{output}])
4634 Insert a reference to derivation output @var{output}, or to the main
4635 output when @var{output} is omitted.
4637 This only makes sense for gexps passed to @code{gexp->derivation}.
4640 @itemx (ungexp-splicing @var{lst})
4641 Like the above, but splices the contents of @var{lst} inside the
4645 @itemx (ungexp-native-splicing @var{lst})
4646 Like the above, but refers to native builds of the objects listed in
4651 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4652 of the @code{gexp?} type (see below.)
4655 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4656 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4657 in their execution environment.
4659 Each item in @var{modules} can be the name of a module, such as
4660 @code{(guix build utils)}, or it can be a module name, followed by an
4661 arrow, followed by a file-like object:
4664 `((guix build utils)
4666 ((guix config) => ,(scheme-file "config.scm"
4667 #~(define-module @dots{}))))
4671 In the example above, the first two modules are taken from the search
4672 path, and the last one is created from the given file-like object.
4674 This form has @emph{lexical} scope: it has an effect on the gexps
4675 directly defined in @var{body}@dots{}, but not on those defined, say, in
4676 procedures called from @var{body}@dots{}.
4679 @deffn {Scheme Procedure} gexp? @var{obj}
4680 Return @code{#t} if @var{obj} is a G-expression.
4683 G-expressions are meant to be written to disk, either as code building
4684 some derivation, or as plain files in the store. The monadic procedures
4685 below allow you to do that (@pxref{The Store Monad}, for more
4686 information about monads.)
4688 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4689 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4690 [#:hash #f] [#:hash-algo #f] @
4691 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4692 [#:module-path @var{%load-path}] @
4693 [#:references-graphs #f] [#:allowed-references #f] @
4694 [#:disallowed-references #f] @
4695 [#:leaked-env-vars #f] @
4696 [#:script-name (string-append @var{name} "-builder")] @
4697 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4698 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4699 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4700 stored in a file called @var{script-name}. When @var{target} is true,
4701 it is used as the cross-compilation target triplet for packages referred
4704 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4706 make @var{modules} available in the evaluation context of @var{exp};
4707 @var{modules} is a list of names of Guile modules searched in
4708 @var{module-path} to be copied in the store, compiled, and made available in
4709 the load path during the execution of @var{exp}---e.g., @code{((guix
4710 build utils) (guix build gnu-build-system))}.
4712 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4715 When @var{references-graphs} is true, it must be a list of tuples of one of the
4719 (@var{file-name} @var{package})
4720 (@var{file-name} @var{package} @var{output})
4721 (@var{file-name} @var{derivation})
4722 (@var{file-name} @var{derivation} @var{output})
4723 (@var{file-name} @var{store-item})
4726 The right-hand-side of each element of @var{references-graphs} is automatically made
4727 an input of the build process of @var{exp}. In the build environment, each
4728 @var{file-name} contains the reference graph of the corresponding item, in a simple
4731 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4732 In the latter case, the list denotes store items that the result is allowed to
4733 refer to. Any reference to another store item will lead to a build error.
4734 Similarly for @var{disallowed-references}, which can list items that must not be
4735 referenced by the outputs.
4737 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4740 @cindex file-like objects
4741 The @code{local-file}, @code{plain-file}, @code{computed-file},
4742 @code{program-file}, and @code{scheme-file} procedures below return
4743 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4744 these objects lead to a file in the store. Consider this G-expression:
4747 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4748 #$(local-file "/tmp/my-nscd.conf"))
4751 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4752 to the store. Once expanded, for instance @i{via}
4753 @code{gexp->derivation}, the G-expression refers to that copy under
4754 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4755 does not have any effect on what the G-expression does.
4756 @code{plain-file} can be used similarly; it differs in that the file
4757 content is directly passed as a string.
4759 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4760 [#:recursive? #f] [#:select? (const #t)]
4761 Return an object representing local file @var{file} to add to the store; this
4762 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4763 up relative to the source file where this form appears. @var{file} will be added to
4764 the store under @var{name}--by default the base name of @var{file}.
4766 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4767 designates a flat file and @var{recursive?} is true, its contents are added, and its
4768 permission bits are kept.
4770 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4771 @var{stat})} for each directory entry, where @var{file} is the entry's
4772 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4773 entries for which @var{select?} does not return true.
4775 This is the declarative counterpart of the @code{interned-file} monadic
4776 procedure (@pxref{The Store Monad, @code{interned-file}}).
4779 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4780 Return an object representing a text file called @var{name} with the given
4781 @var{content} (a string) to be added to the store.
4783 This is the declarative counterpart of @code{text-file}.
4786 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4787 [#:options '(#:local-build? #t)]
4788 Return an object representing the store item @var{name}, a file or
4789 directory computed by @var{gexp}. @var{options}
4790 is a list of additional arguments to pass to @code{gexp->derivation}.
4792 This is the declarative counterpart of @code{gexp->derivation}.
4795 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4796 Return an executable script @var{name} that runs @var{exp} using
4797 @var{guile}, with @var{exp}'s imported modules in its search path.
4799 The example below builds a script that simply invokes the @command{ls}
4803 (use-modules (guix gexp) (gnu packages base))
4805 (gexp->script "list-files"
4806 #~(execl #$(file-append coreutils "/bin/ls")
4810 When ``running'' it through the store (@pxref{The Store Monad,
4811 @code{run-with-store}}), we obtain a derivation that produces an
4812 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4815 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4817 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4821 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4823 Return an object representing the executable store item @var{name} that
4824 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4827 This is the declarative counterpart of @code{gexp->script}.
4830 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4831 [#:set-load-path? #t]
4832 Return a derivation that builds a file @var{name} containing @var{exp}.
4833 When @var{set-load-path?} is true, emit code in the resulting file to
4834 set @code{%load-path} and @code{%load-compiled-path} to honor
4835 @var{exp}'s imported modules.
4837 The resulting file holds references to all the dependencies of @var{exp}
4838 or a subset thereof.
4841 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4842 Return an object representing the Scheme file @var{name} that contains
4845 This is the declarative counterpart of @code{gexp->file}.
4848 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4849 Return as a monadic value a derivation that builds a text file
4850 containing all of @var{text}. @var{text} may list, in addition to
4851 strings, objects of any type that can be used in a gexp: packages,
4852 derivations, local file objects, etc. The resulting store file holds
4853 references to all these.
4855 This variant should be preferred over @code{text-file} anytime the file
4856 to create will reference items from the store. This is typically the
4857 case when building a configuration file that embeds store file names,
4861 (define (profile.sh)
4862 ;; Return the name of a shell script in the store that
4863 ;; initializes the 'PATH' environment variable.
4864 (text-file* "profile.sh"
4865 "export PATH=" coreutils "/bin:"
4866 grep "/bin:" sed "/bin\n"))
4869 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4870 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4871 preventing them from being garbage-collected during its lifetime.
4874 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4875 Return an object representing store file @var{name} containing
4876 @var{text}. @var{text} is a sequence of strings and file-like objects,
4880 (mixed-text-file "profile"
4881 "export PATH=" coreutils "/bin:" grep "/bin")
4884 This is the declarative counterpart of @code{text-file*}.
4887 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4888 Return a file-like object that expands to the concatenation of @var{obj}
4889 and @var{suffix}, where @var{obj} is a lowerable object and each
4890 @var{suffix} is a string.
4892 As an example, consider this gexp:
4895 (gexp->script "run-uname"
4896 #~(system* #$(file-append coreutils
4900 The same effect could be achieved with:
4903 (gexp->script "run-uname"
4904 #~(system* (string-append #$coreutils
4908 There is one difference though: in the @code{file-append} case, the
4909 resulting script contains the absolute file name as a string, whereas in
4910 the second case, the resulting script contains a @code{(string-append
4911 @dots{})} expression to construct the file name @emph{at run time}.
4915 Of course, in addition to gexps embedded in ``host'' code, there are
4916 also modules containing build tools. To make it clear that they are
4917 meant to be used in the build stratum, these modules are kept in the
4918 @code{(guix build @dots{})} name space.
4920 @cindex lowering, of high-level objects in gexps
4921 Internally, high-level objects are @dfn{lowered}, using their compiler,
4922 to either derivations or store items. For instance, lowering a package
4923 yields a derivation, and lowering a @code{plain-file} yields a store
4924 item. This is achieved using the @code{lower-object} monadic procedure.
4926 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4928 Return as a value in @var{%store-monad} the derivation or store item
4929 corresponding to @var{obj} for @var{system}, cross-compiling for
4930 @var{target} if @var{target} is true. @var{obj} must be an object that
4931 has an associated gexp compiler, such as a @code{<package>}.
4935 @c *********************************************************************
4939 This section describes Guix command-line utilities. Some of them are
4940 primarily targeted at developers and users who write new package
4941 definitions, while others are more generally useful. They complement
4942 the Scheme programming interface of Guix in a convenient way.
4945 * Invoking guix build:: Building packages from the command line.
4946 * Invoking guix edit:: Editing package definitions.
4947 * Invoking guix download:: Downloading a file and printing its hash.
4948 * Invoking guix hash:: Computing the cryptographic hash of a file.
4949 * Invoking guix import:: Importing package definitions.
4950 * Invoking guix refresh:: Updating package definitions.
4951 * Invoking guix lint:: Finding errors in package definitions.
4952 * Invoking guix size:: Profiling disk usage.
4953 * Invoking guix graph:: Visualizing the graph of packages.
4954 * Invoking guix environment:: Setting up development environments.
4955 * Invoking guix publish:: Sharing substitutes.
4956 * Invoking guix challenge:: Challenging substitute servers.
4957 * Invoking guix copy:: Copying to and from a remote store.
4958 * Invoking guix container:: Process isolation.
4959 * Invoking guix weather:: Assessing substitute availability.
4962 @node Invoking guix build
4963 @section Invoking @command{guix build}
4965 @cindex package building
4966 @cindex @command{guix build}
4967 The @command{guix build} command builds packages or derivations and
4968 their dependencies, and prints the resulting store paths. Note that it
4969 does not modify the user's profile---this is the job of the
4970 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4971 it is mainly useful for distribution developers.
4973 The general syntax is:
4976 guix build @var{options} @var{package-or-derivation}@dots{}
4979 As an example, the following command builds the latest versions of Emacs
4980 and of Guile, displays their build logs, and finally displays the
4981 resulting directories:
4984 guix build emacs guile
4987 Similarly, the following command builds all the available packages:
4990 guix build --quiet --keep-going \
4991 `guix package -A | cut -f1,2 --output-delimiter=@@`
4994 @var{package-or-derivation} may be either the name of a package found in
4995 the software distribution such as @code{coreutils} or
4996 @code{coreutils@@8.20}, or a derivation such as
4997 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4998 package with the corresponding name (and optionally version) is searched
4999 for among the GNU distribution modules (@pxref{Package Modules}).
5001 Alternatively, the @code{--expression} option may be used to specify a
5002 Scheme expression that evaluates to a package; this is useful when
5003 disambiguating among several same-named packages or package variants is
5006 There may be zero or more @var{options}. The available options are
5007 described in the subsections below.
5010 * Common Build Options:: Build options for most commands.
5011 * Package Transformation Options:: Creating variants of packages.
5012 * Additional Build Options:: Options specific to 'guix build'.
5013 * Debugging Build Failures:: Real life packaging experience.
5016 @node Common Build Options
5017 @subsection Common Build Options
5019 A number of options that control the build process are common to
5020 @command{guix build} and other commands that can spawn builds, such as
5021 @command{guix package} or @command{guix archive}. These are the
5026 @item --load-path=@var{directory}
5027 @itemx -L @var{directory}
5028 Add @var{directory} to the front of the package module search path
5029 (@pxref{Package Modules}).
5031 This allows users to define their own packages and make them visible to
5032 the command-line tools.
5036 Keep the build tree of failed builds. Thus, if a build fails, its build
5037 tree is kept under @file{/tmp}, in a directory whose name is shown at
5038 the end of the build log. This is useful when debugging build issues.
5039 @xref{Debugging Build Failures}, for tips and tricks on how to debug
5044 Keep going when some of the derivations fail to build; return only once
5045 all the builds have either completed or failed.
5047 The default behavior is to stop as soon as one of the specified
5048 derivations has failed.
5052 Do not build the derivations.
5055 When substituting a pre-built binary fails, fall back to building
5058 @item --substitute-urls=@var{urls}
5059 @anchor{client-substitute-urls}
5060 Consider @var{urls} the whitespace-separated list of substitute source
5061 URLs, overriding the default list of URLs of @command{guix-daemon}
5062 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
5064 This means that substitutes may be downloaded from @var{urls}, provided
5065 they are signed by a key authorized by the system administrator
5066 (@pxref{Substitutes}).
5068 When @var{urls} is the empty string, substitutes are effectively
5071 @item --no-substitutes
5072 Do not use substitutes for build products. That is, always build things
5073 locally instead of allowing downloads of pre-built binaries
5074 (@pxref{Substitutes}).
5077 Do not ``graft'' packages. In practice, this means that package updates
5078 available as grafts are not applied. @xref{Security Updates}, for more
5079 information on grafts.
5081 @item --rounds=@var{n}
5082 Build each derivation @var{n} times in a row, and raise an error if
5083 consecutive build results are not bit-for-bit identical.
5085 This is a useful way to detect non-deterministic builds processes.
5086 Non-deterministic build processes are a problem because they make it
5087 practically impossible for users to @emph{verify} whether third-party
5088 binaries are genuine. @xref{Invoking guix challenge}, for more.
5090 Note that, currently, the differing build results are not kept around,
5091 so you will have to manually investigate in case of an error---e.g., by
5092 stashing one of the build results with @code{guix archive --export}
5093 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5096 @item --no-build-hook
5097 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5098 (@pxref{Daemon Offload Setup}). That is, always build things locally
5099 instead of offloading builds to remote machines.
5101 @item --max-silent-time=@var{seconds}
5102 When the build or substitution process remains silent for more than
5103 @var{seconds}, terminate it and report a build failure.
5105 By default, the daemon's setting is honored (@pxref{Invoking
5106 guix-daemon, @code{--max-silent-time}}).
5108 @item --timeout=@var{seconds}
5109 Likewise, when the build or substitution process lasts for more than
5110 @var{seconds}, terminate it and report a build failure.
5112 By default, the daemon's setting is honored (@pxref{Invoking
5113 guix-daemon, @code{--timeout}}).
5115 @item --verbosity=@var{level}
5116 Use the given verbosity level. @var{level} must be an integer between 0
5117 and 5; higher means more verbose output. Setting a level of 4 or more
5118 may be helpful when debugging setup issues with the build daemon.
5120 @item --cores=@var{n}
5122 Allow the use of up to @var{n} CPU cores for the build. The special
5123 value @code{0} means to use as many CPU cores as available.
5125 @item --max-jobs=@var{n}
5127 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5128 guix-daemon, @code{--max-jobs}}, for details about this option and the
5129 equivalent @command{guix-daemon} option.
5133 Behind the scenes, @command{guix build} is essentially an interface to
5134 the @code{package-derivation} procedure of the @code{(guix packages)}
5135 module, and to the @code{build-derivations} procedure of the @code{(guix
5136 derivations)} module.
5138 In addition to options explicitly passed on the command line,
5139 @command{guix build} and other @command{guix} commands that support
5140 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5142 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5143 Users can define this variable to a list of command line options that
5144 will automatically be used by @command{guix build} and other
5145 @command{guix} commands that can perform builds, as in the example
5149 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5152 These options are parsed independently, and the result is appended to
5153 the parsed command-line options.
5157 @node Package Transformation Options
5158 @subsection Package Transformation Options
5160 @cindex package variants
5161 Another set of command-line options supported by @command{guix build}
5162 and also @command{guix package} are @dfn{package transformation
5163 options}. These are options that make it possible to define @dfn{package
5164 variants}---for instance, packages built from different source code.
5165 This is a convenient way to create customized packages on the fly
5166 without having to type in the definitions of package variants
5167 (@pxref{Defining Packages}).
5171 @item --with-source=@var{source}
5172 Use @var{source} as the source of the corresponding package.
5173 @var{source} must be a file name or a URL, as for @command{guix
5174 download} (@pxref{Invoking guix download}).
5176 The ``corresponding package'' is taken to be the one specified on the
5177 command line the name of which matches the base of @var{source}---e.g.,
5178 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5179 package is @code{guile}. Likewise, the version string is inferred from
5180 @var{source}; in the previous example, it is @code{2.0.10}.
5182 This option allows users to try out versions of packages other than the
5183 one provided by the distribution. The example below downloads
5184 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5185 the @code{ed} package:
5188 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5191 As a developer, @code{--with-source} makes it easy to test release
5195 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5198 @dots{} or to build from a checkout in a pristine environment:
5201 $ git clone git://git.sv.gnu.org/guix.git
5202 $ guix build guix --with-source=./guix
5205 @item --with-input=@var{package}=@var{replacement}
5206 Replace dependency on @var{package} by a dependency on
5207 @var{replacement}. @var{package} must be a package name, and
5208 @var{replacement} must be a package specification such as @code{guile}
5209 or @code{guile@@1.8}.
5211 For instance, the following command builds Guix, but replaces its
5212 dependency on the current stable version of Guile with a dependency on
5213 the legacy version of Guile, @code{guile@@2.0}:
5216 guix build --with-input=guile=guile@@2.0 guix
5219 This is a recursive, deep replacement. So in this example, both
5220 @code{guix} and its dependency @code{guile-json} (which also depends on
5221 @code{guile}) get rebuilt against @code{guile@@2.0}.
5223 This is implemented using the @code{package-input-rewriting} Scheme
5224 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5226 @item --with-graft=@var{package}=@var{replacement}
5227 This is similar to @code{--with-input} but with an important difference:
5228 instead of rebuilding the whole dependency chain, @var{replacement} is
5229 built and then @dfn{grafted} onto the binaries that were initially
5230 referring to @var{package}. @xref{Security Updates}, for more
5231 information on grafts.
5233 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5234 and all its dependencies, replacing references to the version of GnuTLS
5235 they currently refer to:
5238 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5241 This has the advantage of being much faster than rebuilding everything.
5242 But there is a caveat: it works if and only if @var{package} and
5243 @var{replacement} are strictly compatible---for example, if they provide
5244 a library, the application binary interface (ABI) of those libraries
5245 must be compatible. If @var{replacement} is somehow incompatible with
5246 @var{package}, then the resulting package may be unusable. Use with
5251 @node Additional Build Options
5252 @subsection Additional Build Options
5254 The command-line options presented below are specific to @command{guix
5261 Build quietly, without displaying the build log. Upon completion, the
5262 build log is kept in @file{/var} (or similar) and can always be
5263 retrieved using the @option{--log-file} option.
5265 @item --file=@var{file}
5266 @itemx -f @var{file}
5268 Build the package or derivation that the code within @var{file}
5271 As an example, @var{file} might contain a package definition like this
5272 (@pxref{Defining Packages}):
5275 @verbatiminclude package-hello.scm
5278 @item --expression=@var{expr}
5279 @itemx -e @var{expr}
5280 Build the package or derivation @var{expr} evaluates to.
5282 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5283 guile-1.8)}, which unambiguously designates this specific variant of
5284 version 1.8 of Guile.
5286 Alternatively, @var{expr} may be a G-expression, in which case it is used
5287 as a build program passed to @code{gexp->derivation}
5288 (@pxref{G-Expressions}).
5290 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5291 (@pxref{The Store Monad}). The procedure must return a derivation as a
5292 monadic value, which is then passed through @code{run-with-store}.
5296 Build the source derivations of the packages, rather than the packages
5299 For instance, @code{guix build -S gcc} returns something like
5300 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5303 The returned source tarball is the result of applying any patches and
5304 code snippets specified in the package @code{origin} (@pxref{Defining
5308 Fetch and return the source of @var{package-or-derivation} and all their
5309 dependencies, recursively. This is a handy way to obtain a local copy
5310 of all the source code needed to build @var{packages}, allowing you to
5311 eventually build them even without network access. It is an extension
5312 of the @code{--source} option and can accept one of the following
5313 optional argument values:
5317 This value causes the @code{--sources} option to behave in the same way
5318 as the @code{--source} option.
5321 Build the source derivations of all packages, including any source that
5322 might be listed as @code{inputs}. This is the default value.
5325 $ guix build --sources tzdata
5326 The following derivations will be built:
5327 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5328 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5332 Build the source derivations of all packages, as well of all transitive
5333 inputs to the packages. This can be used e.g. to
5334 prefetch package source for later offline building.
5337 $ guix build --sources=transitive tzdata
5338 The following derivations will be built:
5339 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5340 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5341 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5342 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5343 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5344 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5350 @item --system=@var{system}
5351 @itemx -s @var{system}
5352 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5353 the system type of the build host.
5355 An example use of this is on Linux-based systems, which can emulate
5356 different personalities. For instance, passing
5357 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5358 to build packages in a complete 32-bit environment.
5360 @item --target=@var{triplet}
5361 @cindex cross-compilation
5362 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5363 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5364 configuration triplets,, autoconf, Autoconf}).
5366 @anchor{build-check}
5368 @cindex determinism, checking
5369 @cindex reproducibility, checking
5370 Rebuild @var{package-or-derivation}, which are already available in the
5371 store, and raise an error if the build results are not bit-for-bit
5374 This mechanism allows you to check whether previously installed
5375 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5376 of a package is deterministic. @xref{Invoking guix challenge}, for more
5377 background information and tools.
5379 When used in conjunction with @option{--keep-failed}, the differing
5380 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5381 This makes it easy to look for differences between the two results.
5384 @cindex repairing store items
5385 @cindex corruption, recovering from
5386 Attempt to repair the specified store items, if they are corrupt, by
5387 re-downloading or rebuilding them.
5389 This operation is not atomic and thus restricted to @code{root}.
5393 Return the derivation paths, not the output paths, of the given
5396 @item --root=@var{file}
5397 @itemx -r @var{file}
5398 Make @var{file} a symlink to the result, and register it as a garbage
5402 Return the build log file names or URLs for the given
5403 @var{package-or-derivation}, or raise an error if build logs are
5406 This works regardless of how packages or derivations are specified. For
5407 instance, the following invocations are equivalent:
5410 guix build --log-file `guix build -d guile`
5411 guix build --log-file `guix build guile`
5412 guix build --log-file guile
5413 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5416 If a log is unavailable locally, and unless @code{--no-substitutes} is
5417 passed, the command looks for a corresponding log on one of the
5418 substitute servers (as specified with @code{--substitute-urls}.)
5420 So for instance, imagine you want to see the build log of GDB on MIPS,
5421 but you are actually on an @code{x86_64} machine:
5424 $ guix build --log-file gdb -s mips64el-linux
5425 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5428 You can freely access a huge library of build logs!
5431 @node Debugging Build Failures
5432 @subsection Debugging Build Failures
5434 @cindex build failures, debugging
5435 When defining a new package (@pxref{Defining Packages}), you will
5436 probably find yourself spending some time debugging and tweaking the
5437 build until it succeeds. To do that, you need to operate the build
5438 commands yourself in an environment as close as possible to the one the
5441 To that end, the first thing to do is to use the @option{--keep-failed}
5442 or @option{-K} option of @command{guix build}, which will keep the
5443 failed build tree in @file{/tmp} or whatever directory you specified as
5444 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5446 From there on, you can @command{cd} to the failed build tree and source
5447 the @file{environment-variables} file, which contains all the
5448 environment variable definitions that were in place when the build
5449 failed. So let's say you're debugging a build failure in package
5450 @code{foo}; a typical session would look like this:
5454 @dots{} @i{build fails}
5455 $ cd /tmp/guix-build-foo.drv-0
5456 $ source ./environment-variables
5460 Now, you can invoke commands as if you were the daemon (almost) and
5461 troubleshoot your build process.
5463 Sometimes it happens that, for example, a package's tests pass when you
5464 run them manually but they fail when the daemon runs them. This can
5465 happen because the daemon runs builds in containers where, unlike in our
5466 environment above, network access is missing, @file{/bin/sh} does not
5467 exist, etc. (@pxref{Build Environment Setup}).
5469 In such cases, you may need to run inspect the build process from within
5470 a container similar to the one the build daemon creates:
5475 $ cd /tmp/guix-build-foo.drv-0
5476 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5477 [env]# source ./environment-variables
5481 Here, @command{guix environment -C} creates a container and spawns a new
5482 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5483 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5484 the container, which would may find handy while debugging. The
5485 @option{--no-grafts} option makes sure we get the exact same
5486 environment, with ungrafted packages (@pxref{Security Updates}, for more
5489 To get closer to a container like that used by the build daemon, we can
5490 remove @file{/bin/sh}:
5496 (Don't worry, this is harmless: this is all happening in the throw-away
5497 container created by @command{guix environment}.)
5499 The @command{strace} command is probably not in the search path, but we
5503 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5506 In this way, not only you will have reproduced the environment variables
5507 the daemon uses, you will also be running the build process in a container
5508 similar to the one the daemon uses.
5511 @node Invoking guix edit
5512 @section Invoking @command{guix edit}
5514 @cindex @command{guix edit}
5515 @cindex package definition, editing
5516 So many packages, so many source files! The @command{guix edit} command
5517 facilitates the life of users and packagers by pointing their editor at
5518 the source file containing the definition of the specified packages.
5522 guix edit gcc@@4.9 vim
5526 launches the program specified in the @code{VISUAL} or in the
5527 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5530 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5531 have created your own packages on @code{GUIX_PACKAGE_PATH}
5532 (@pxref{Defining Packages}), you will be able to edit the package
5533 recipes. Otherwise, you will be able to examine the read-only recipes
5534 for packages currently in the store.
5537 @node Invoking guix download
5538 @section Invoking @command{guix download}
5540 @cindex @command{guix download}
5541 @cindex downloading package sources
5542 When writing a package definition, developers typically need to download
5543 a source tarball, compute its SHA256 hash, and write that
5544 hash in the package definition (@pxref{Defining Packages}). The
5545 @command{guix download} tool helps with this task: it downloads a file
5546 from the given URI, adds it to the store, and prints both its file name
5547 in the store and its SHA256 hash.
5549 The fact that the downloaded file is added to the store saves bandwidth:
5550 when the developer eventually tries to build the newly defined package
5551 with @command{guix build}, the source tarball will not have to be
5552 downloaded again because it is already in the store. It is also a
5553 convenient way to temporarily stash files, which may be deleted
5554 eventually (@pxref{Invoking guix gc}).
5556 The @command{guix download} command supports the same URIs as used in
5557 package definitions. In particular, it supports @code{mirror://} URIs.
5558 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5559 Guile bindings for GnuTLS are available in the user's environment; when
5560 they are not available, an error is raised. @xref{Guile Preparations,
5561 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5562 GnuTLS-Guile}, for more information.
5564 @command{guix download} verifies HTTPS server certificates by loading
5565 the certificates of X.509 authorities from the directory pointed to by
5566 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5567 Certificates}), unless @option{--no-check-certificate} is used.
5569 The following options are available:
5572 @item --format=@var{fmt}
5574 Write the hash in the format specified by @var{fmt}. For more
5575 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5577 @item --no-check-certificate
5578 Do not validate the X.509 certificates of HTTPS servers.
5580 When using this option, you have @emph{absolutely no guarantee} that you
5581 are communicating with the authentic server responsible for the given
5582 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5584 @item --output=@var{file}
5585 @itemx -o @var{file}
5586 Save the downloaded file to @var{file} instead of adding it to the
5590 @node Invoking guix hash
5591 @section Invoking @command{guix hash}
5593 @cindex @command{guix hash}
5594 The @command{guix hash} command computes the SHA256 hash of a file.
5595 It is primarily a convenience tool for anyone contributing to the
5596 distribution: it computes the cryptographic hash of a file, which can be
5597 used in the definition of a package (@pxref{Defining Packages}).
5599 The general syntax is:
5602 guix hash @var{option} @var{file}
5605 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5606 hash of data read from standard input. @command{guix hash} has the
5611 @item --format=@var{fmt}
5613 Write the hash in the format specified by @var{fmt}.
5615 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5616 (@code{hex} and @code{hexadecimal} can be used as well).
5618 If the @option{--format} option is not specified, @command{guix hash}
5619 will output the hash in @code{nix-base32}. This representation is used
5620 in the definitions of packages.
5624 Compute the hash on @var{file} recursively.
5626 In this case, the hash is computed on an archive containing @var{file},
5627 including its children if it is a directory. Some of the metadata of
5628 @var{file} is part of the archive; for instance, when @var{file} is a
5629 regular file, the hash is different depending on whether @var{file} is
5630 executable or not. Metadata such as time stamps has no impact on the
5631 hash (@pxref{Invoking guix archive}).
5632 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5637 When combined with @option{--recursive}, exclude version control system
5638 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5641 As an example, here is how you would compute the hash of a Git checkout,
5642 which is useful when using the @code{git-fetch} method (@pxref{origin
5646 $ git clone http://example.org/foo.git
5652 @node Invoking guix import
5653 @section Invoking @command{guix import}
5655 @cindex importing packages
5656 @cindex package import
5657 @cindex package conversion
5658 @cindex Invoking @command{guix import}
5659 The @command{guix import} command is useful for people who would like to
5660 add a package to the distribution with as little work as
5661 possible---a legitimate demand. The command knows of a few
5662 repositories from which it can ``import'' package metadata. The result
5663 is a package definition, or a template thereof, in the format we know
5664 (@pxref{Defining Packages}).
5666 The general syntax is:
5669 guix import @var{importer} @var{options}@dots{}
5672 @var{importer} specifies the source from which to import package
5673 metadata, and @var{options} specifies a package identifier and other
5674 options specific to @var{importer}. Currently, the available
5679 Import metadata for the given GNU package. This provides a template
5680 for the latest version of that GNU package, including the hash of its
5681 source tarball, and its canonical synopsis and description.
5683 Additional information such as the package dependencies and its
5684 license needs to be figured out manually.
5686 For example, the following command returns a package definition for
5690 guix import gnu hello
5693 Specific command-line options are:
5696 @item --key-download=@var{policy}
5697 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5698 keys when verifying the package signature. @xref{Invoking guix
5699 refresh, @code{--key-download}}.
5704 Import metadata from the @uref{https://pypi.python.org/, Python Package
5705 Index}@footnote{This functionality requires Guile-JSON to be installed.
5706 @xref{Requirements}.}. Information is taken from the JSON-formatted
5707 description available at @code{pypi.python.org} and usually includes all
5708 the relevant information, including package dependencies. For maximum
5709 efficiency, it is recommended to install the @command{unzip} utility, so
5710 that the importer can unzip Python wheels and gather data from them.
5712 The command below imports metadata for the @code{itsdangerous} Python
5716 guix import pypi itsdangerous
5721 Import metadata from @uref{https://rubygems.org/,
5722 RubyGems}@footnote{This functionality requires Guile-JSON to be
5723 installed. @xref{Requirements}.}. Information is taken from the
5724 JSON-formatted description available at @code{rubygems.org} and includes
5725 most relevant information, including runtime dependencies. There are
5726 some caveats, however. The metadata doesn't distinguish between
5727 synopses and descriptions, so the same string is used for both fields.
5728 Additionally, the details of non-Ruby dependencies required to build
5729 native extensions is unavailable and left as an exercise to the
5732 The command below imports metadata for the @code{rails} Ruby package:
5735 guix import gem rails
5740 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5741 functionality requires Guile-JSON to be installed.
5742 @xref{Requirements}.}.
5743 Information is taken from the JSON-formatted metadata provided through
5744 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5745 relevant information, such as module dependencies. License information
5746 should be checked closely. If Perl is available in the store, then the
5747 @code{corelist} utility will be used to filter core modules out of the
5748 list of dependencies.
5750 The command command below imports metadata for the @code{Acme::Boolean}
5754 guix import cpan Acme::Boolean
5759 @cindex Bioconductor
5760 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5761 central repository for the @uref{http://r-project.org, GNU@tie{}R
5762 statistical and graphical environment}.
5764 Information is extracted from the @code{DESCRIPTION} file of the package.
5766 The command command below imports metadata for the @code{Cairo}
5770 guix import cran Cairo
5773 When @code{--recursive} is added, the importer will traverse the
5774 dependency graph of the given upstream package recursively and generate
5775 package expressions for all those packages that are not yet in Guix.
5777 When @code{--archive=bioconductor} is added, metadata is imported from
5778 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5779 packages for for the analysis and comprehension of high-throughput
5780 genomic data in bioinformatics.
5782 Information is extracted from the @code{DESCRIPTION} file of a package
5783 published on the web interface of the Bioconductor SVN repository.
5785 The command below imports metadata for the @code{GenomicRanges}
5789 guix import cran --archive=bioconductor GenomicRanges
5795 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5796 comprehensive TeX archive network for TeX packages that are part of the
5797 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5799 Information about the package is obtained through the XML API provided
5800 by CTAN, while the source code is downloaded from the SVN repository of
5801 the Tex Live project. This is done because the CTAN does not keep
5804 The command command below imports metadata for the @code{fontspec}
5808 guix import texlive fontspec
5811 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5812 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5813 tree in the TeX Live SVN repository, but from the specified sibling
5814 directory under the same root.
5816 The command below imports metadata for the @code{ifxetex} package from
5817 CTAN while fetching the sources from the directory
5818 @file{texmf/source/generic}:
5821 guix import texlive --archive=generic ifxetex
5825 Import metadata from a local copy of the source of the
5826 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5827 relies on the @command{nix-instantiate} command of
5828 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5829 typically written in a mixture of Nix-language and Bash code. This
5830 command only imports the high-level package structure that is written in
5831 the Nix language. It normally includes all the basic fields of a
5834 When importing a GNU package, the synopsis and descriptions are replaced
5835 by their canonical upstream variant.
5837 Usually, you will first need to do:
5840 export NIX_REMOTE=daemon
5844 so that @command{nix-instantiate} does not try to open the Nix database.
5846 As an example, the command below imports the package definition of
5847 LibreOffice (more precisely, it imports the definition of the package
5848 bound to the @code{libreoffice} top-level attribute):
5851 guix import nix ~/path/to/nixpkgs libreoffice
5856 Import metadata from the Haskell community's central package archive
5857 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5858 Cabal files and includes all the relevant information, including package
5861 Specific command-line options are:
5866 Read a Cabal file from standard input.
5867 @item --no-test-dependencies
5869 Do not include dependencies required only by the test suites.
5870 @item --cabal-environment=@var{alist}
5871 @itemx -e @var{alist}
5872 @var{alist} is a Scheme alist defining the environment in which the
5873 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5874 @code{arch}, @code{impl} and a string representing the name of a flag.
5875 The value associated with a flag has to be either the symbol
5876 @code{true} or @code{false}. The value associated with other keys
5877 has to conform to the Cabal file format definition. The default value
5878 associated with the keys @code{os}, @code{arch} and @code{impl} is
5879 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5882 The command below imports metadata for the latest version of the
5883 @code{HTTP} Haskell package without including test dependencies and
5884 specifying the value of the flag @samp{network-uri} as @code{false}:
5887 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5890 A specific package version may optionally be specified by following the
5891 package name by an at-sign and a version number as in the following example:
5894 guix import hackage mtl@@2.1.3.1
5899 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5900 It takes a package name, looks up the package version included in a
5901 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5902 release and uses the @code{hackage} importer to retrieve its metadata.
5903 Note that it is up to you to select an LTS release compatible with the
5904 GHC compiler used by Guix.
5906 Specific command-line options are:
5909 @item --no-test-dependencies
5911 Do not include dependencies required only by the test suites.
5912 @item --lts-version=@var{version}
5913 @itemx -r @var{version}
5914 @var{version} is the desired LTS release version. If omitted the latest
5918 The command below imports metadata for the @code{HTTP} Haskell package
5919 included in the LTS Stackage release version 7.18:
5922 guix import stackage --lts-version=7.18 HTTP
5927 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5928 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5930 Specific command-line options are:
5933 @item --archive=@var{repo}
5934 @itemx -a @var{repo}
5935 @var{repo} identifies the archive repository from which to retrieve the
5936 information. Currently the supported repositories and their identifiers
5940 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5941 identifier. This is the default.
5943 Packages from @code{elpa.gnu.org} are signed with one of the keys
5944 contained in the GnuPG keyring at
5945 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5946 @code{emacs} package (@pxref{Package Installation, ELPA package
5947 signatures,, emacs, The GNU Emacs Manual}).
5950 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5951 @code{melpa-stable} identifier.
5954 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5961 Import metadata from the crates.io Rust package repository
5962 @uref{https://crates.io, crates.io}.
5965 The structure of the @command{guix import} code is modular. It would be
5966 useful to have more importers for other package formats, and your help
5967 is welcome here (@pxref{Contributing}).
5969 @node Invoking guix refresh
5970 @section Invoking @command{guix refresh}
5972 @cindex @command {guix refresh}
5973 The primary audience of the @command{guix refresh} command is developers
5974 of the GNU software distribution. By default, it reports any packages
5975 provided by the distribution that are outdated compared to the latest
5976 upstream version, like this:
5980 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5981 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5984 Alternately, one can specify packages to consider, in which case a
5985 warning is emitted for packages that lack an updater:
5988 $ guix refresh coreutils guile guile-ssh
5989 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5990 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5993 @command{guix refresh} browses the upstream repository of each package and determines
5994 the highest version number of the releases therein. The command
5995 knows how to update specific types of packages: GNU packages, ELPA
5996 packages, etc.---see the documentation for @option{--type} below. There
5997 are many packages, though, for which it lacks a method to determine
5998 whether a new upstream release is available. However, the mechanism is
5999 extensible, so feel free to get in touch with us to add a new method!
6001 When passed @code{--update}, it modifies distribution source files to
6002 update the version numbers and source tarball hashes of those package
6003 recipes (@pxref{Defining Packages}). This is achieved by downloading
6004 each package's latest source tarball and its associated OpenPGP
6005 signature, authenticating the downloaded tarball against its signature
6006 using @command{gpg}, and finally computing its hash. When the public
6007 key used to sign the tarball is missing from the user's keyring, an
6008 attempt is made to automatically retrieve it from a public key server;
6009 when this is successful, the key is added to the user's keyring; otherwise,
6010 @command{guix refresh} reports an error.
6012 The following options are supported:
6016 @item --expression=@var{expr}
6017 @itemx -e @var{expr}
6018 Consider the package @var{expr} evaluates to.
6020 This is useful to precisely refer to a package, as in this example:
6023 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
6026 This command lists the dependents of the ``final'' libc (essentially all
6031 Update distribution source files (package recipes) in place. This is
6032 usually run from a checkout of the Guix source tree (@pxref{Running
6033 Guix Before It Is Installed}):
6036 $ ./pre-inst-env guix refresh -s non-core -u
6039 @xref{Defining Packages}, for more information on package definitions.
6041 @item --select=[@var{subset}]
6042 @itemx -s @var{subset}
6043 Select all the packages in @var{subset}, one of @code{core} or
6046 The @code{core} subset refers to all the packages at the core of the
6047 distribution---i.e., packages that are used to build ``everything
6048 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
6049 changing one of these packages in the distribution entails a rebuild of
6050 all the others. Thus, such updates are an inconvenience to users in
6051 terms of build time or bandwidth used to achieve the upgrade.
6053 The @code{non-core} subset refers to the remaining packages. It is
6054 typically useful in cases where an update of the core packages would be
6057 @item --manifest=@var{file}
6058 @itemx -m @var{file}
6059 Select all the packages from the manifest in @var{file}. This is useful to
6060 check if any packages of the user manifest can be updated.
6062 @item --type=@var{updater}
6063 @itemx -t @var{updater}
6064 Select only packages handled by @var{updater} (may be a comma-separated
6065 list of updaters). Currently, @var{updater} may be one of:
6069 the updater for GNU packages;
6071 the updater for GNOME packages;
6073 the updater for KDE packages;
6075 the updater for X.org packages;
6077 the updater for packages hosted on kernel.org;
6079 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
6081 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
6083 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
6085 the updater for @uref{http://www.cpan.org/, CPAN} packages;
6087 the updater for @uref{https://pypi.python.org, PyPI} packages.
6089 the updater for @uref{https://rubygems.org, RubyGems} packages.
6091 the updater for @uref{https://github.com, GitHub} packages.
6093 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6095 the updater for @uref{https://www.stackage.org, Stackage} packages.
6097 the updater for @uref{https://crates.io, Crates} packages.
6100 For instance, the following command only checks for updates of Emacs
6101 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6104 $ guix refresh --type=elpa,cran
6105 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6106 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6111 In addition, @command{guix refresh} can be passed one or more package
6112 names, as in this example:
6115 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6119 The command above specifically updates the @code{emacs} and
6120 @code{idutils} packages. The @code{--select} option would have no
6121 effect in this case.
6123 When considering whether to upgrade a package, it is sometimes
6124 convenient to know which packages would be affected by the upgrade and
6125 should be checked for compatibility. For this the following option may
6126 be used when passing @command{guix refresh} one or more package names:
6130 @item --list-updaters
6132 List available updaters and exit (see @option{--type} above.)
6134 For each updater, display the fraction of packages it covers; at the
6135 end, display the fraction of packages covered by all these updaters.
6137 @item --list-dependent
6139 List top-level dependent packages that would need to be rebuilt as a
6140 result of upgrading one or more packages.
6142 @xref{Invoking guix graph, the @code{reverse-package} type of
6143 @command{guix graph}}, for information on how to visualize the list of
6144 dependents of a package.
6148 Be aware that the @code{--list-dependent} option only
6149 @emph{approximates} the rebuilds that would be required as a result of
6150 an upgrade. More rebuilds might be required under some circumstances.
6153 $ guix refresh --list-dependent flex
6154 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6155 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6158 The command above lists a set of packages that could be built to check
6159 for compatibility with an upgraded @code{flex} package.
6161 The following options can be used to customize GnuPG operation:
6165 @item --gpg=@var{command}
6166 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6167 for in @code{$PATH}.
6169 @item --key-download=@var{policy}
6170 Handle missing OpenPGP keys according to @var{policy}, which may be one
6175 Always download missing OpenPGP keys from the key server, and add them
6176 to the user's GnuPG keyring.
6179 Never try to download missing OpenPGP keys. Instead just bail out.
6182 When a package signed with an unknown OpenPGP key is encountered, ask
6183 the user whether to download it or not. This is the default behavior.
6186 @item --key-server=@var{host}
6187 Use @var{host} as the OpenPGP key server when importing a public key.
6191 The @code{github} updater uses the
6192 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6193 releases. When used repeatedly e.g. when refreshing all packages,
6194 GitHub will eventually refuse to answer any further API requests. By
6195 default 60 API requests per hour are allowed, and a full refresh on all
6196 GitHub packages in Guix requires more than this. Authentication with
6197 GitHub through the use of an API token alleviates these limits. To use
6198 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6199 token procured from @uref{https://github.com/settings/tokens} or
6203 @node Invoking guix lint
6204 @section Invoking @command{guix lint}
6206 @cindex @command{guix lint}
6207 @cindex package, checking for errors
6208 The @command{guix lint} command is meant to help package developers avoid
6209 common errors and use a consistent style. It runs a number of checks on
6210 a given set of packages in order to find common mistakes in their
6211 definitions. Available @dfn{checkers} include (see
6212 @code{--list-checkers} for a complete list):
6217 Validate certain typographical and stylistic rules about package
6218 descriptions and synopses.
6220 @item inputs-should-be-native
6221 Identify inputs that should most likely be native inputs.
6226 @itemx source-file-name
6227 Probe @code{home-page} and @code{source} URLs and report those that are
6228 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6229 the source file name is meaningful, e.g. is not
6230 just a version number or ``git-checkout'', without a declared
6231 @code{file-name} (@pxref{origin Reference}).
6234 @cindex security vulnerabilities
6235 @cindex CVE, Common Vulnerabilities and Exposures
6236 Report known vulnerabilities found in the Common Vulnerabilities and
6237 Exposures (CVE) databases of the current and past year
6238 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6241 To view information about a particular vulnerability, visit pages such as:
6245 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6247 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6251 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6252 @code{CVE-2015-7554}.
6254 Package developers can specify in package recipes the
6255 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6256 name and version of the package when they differ from the name that Guix
6257 uses, as in this example:
6263 ;; CPE calls this package "grub2".
6264 (properties '((cpe-name . "grub2"))))
6268 Warn about obvious source code formatting issues: trailing white space,
6269 use of tabulations, etc.
6272 The general syntax is:
6275 guix lint @var{options} @var{package}@dots{}
6278 If no package is given on the command line, then all packages are checked.
6279 The @var{options} may be zero or more of the following:
6282 @item --list-checkers
6284 List and describe all the available checkers that will be run on packages
6289 Only enable the checkers specified in a comma-separated list using the
6290 names returned by @code{--list-checkers}.
6294 @node Invoking guix size
6295 @section Invoking @command{guix size}
6298 @cindex package size
6300 @cindex @command{guix size}
6301 The @command{guix size} command helps package developers profile the
6302 disk usage of packages. It is easy to overlook the impact of an
6303 additional dependency added to a package, or the impact of using a
6304 single output for a package that could easily be split (@pxref{Packages
6305 with Multiple Outputs}). Such are the typical issues that
6306 @command{guix size} can highlight.
6308 The command can be passed a package specification such as @code{gcc@@4.8}
6309 or @code{guile:debug}, or a file name in the store. Consider this
6313 $ guix size coreutils
6314 store item total self
6315 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6316 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6317 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6318 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6319 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6320 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6324 The store items listed here constitute the @dfn{transitive closure} of
6325 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6326 would be returned by:
6329 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6332 Here the output shows three columns next to store items. The first column,
6333 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6334 the store item---that is, its own size plus the size of all its
6335 dependencies. The next column, labeled ``self'', shows the size of the
6336 item itself. The last column shows the ratio of the size of the item
6337 itself to the space occupied by all the items listed here.
6339 In this example, we see that the closure of Coreutils weighs in at
6340 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6341 large fraction of the closure is not a problem @i{per se} because it is
6342 always available on the system anyway.)
6344 When the package passed to @command{guix size} is available in the
6345 store, @command{guix size} queries the daemon to determine its
6346 dependencies, and measures its size in the store, similar to @command{du
6347 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6350 When the given package is @emph{not} in the store, @command{guix size}
6351 reports information based on the available substitutes
6352 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6353 store items that are not even on disk, only available remotely.
6355 You can also specify several package names:
6358 $ guix size coreutils grep sed bash
6359 store item total self
6360 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6361 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6362 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6363 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6369 In this example we see that the combination of the four packages takes
6370 102.3@tie{}MiB in total, which is much less than the sum of each closure
6371 since they have a lot of dependencies in common.
6373 The available options are:
6377 @item --substitute-urls=@var{urls}
6378 Use substitute information from @var{urls}.
6379 @xref{client-substitute-urls, the same option for @code{guix build}}.
6381 @item --sort=@var{key}
6382 Sort lines according to @var{key}, one of the following options:
6386 the total size of the item's closure (the default);
6388 the size of each item.
6391 @item --map-file=@var{file}
6392 Write a graphical map of disk usage in PNG format to @var{file}.
6394 For the example above, the map looks like this:
6396 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6397 produced by @command{guix size}}
6399 This option requires that
6400 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6401 installed and visible in Guile's module search path. When that is not
6402 the case, @command{guix size} fails as it tries to load it.
6404 @item --system=@var{system}
6405 @itemx -s @var{system}
6406 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6410 @node Invoking guix graph
6411 @section Invoking @command{guix graph}
6414 @cindex @command{guix graph}
6415 @cindex package dependencies
6416 Packages and their dependencies form a @dfn{graph}, specifically a
6417 directed acyclic graph (DAG). It can quickly become difficult to have a
6418 mental model of the package DAG, so the @command{guix graph} command
6419 provides a visual representation of the DAG. By default,
6420 @command{guix graph} emits a DAG representation in the input format of
6421 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6422 directly to the @command{dot} command of Graphviz. It can also emit an
6423 HTML page with embedded JavaScript code to display a ``chord diagram''
6424 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6425 emit Cypher queries to construct a graph in a graph database supporting
6426 the @uref{http://www.opencypher.org/, openCypher} query language.
6427 The general syntax is:
6430 guix graph @var{options} @var{package}@dots{}
6433 For example, the following command generates a PDF file representing the
6434 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6438 guix graph coreutils | dot -Tpdf > dag.pdf
6441 The output looks like this:
6443 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6445 Nice little graph, no?
6447 But there is more than one graph! The one above is concise: it is the
6448 graph of package objects, omitting implicit inputs such as GCC, libc,
6449 grep, etc. It is often useful to have such a concise graph, but
6450 sometimes one may want to see more details. @command{guix graph} supports
6451 several types of graphs, allowing you to choose the level of detail:
6455 This is the default type used in the example above. It shows the DAG of
6456 package objects, excluding implicit dependencies. It is concise, but
6457 filters out many details.
6459 @item reverse-package
6460 This shows the @emph{reverse} DAG of packages. For example:
6463 guix graph --type=reverse-package ocaml
6466 ... yields the graph of packages that depend on OCaml.
6468 Note that for core packages this can yield huge graphs. If all you want
6469 is to know the number of packages that depend on a given package, use
6470 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6471 @option{--list-dependent}}).
6474 This is the package DAG, @emph{including} implicit inputs.
6476 For instance, the following command:
6479 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6482 ... yields this bigger graph:
6484 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6486 At the bottom of the graph, we see all the implicit inputs of
6487 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6489 Now, note that the dependencies of these implicit inputs---that is, the
6490 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6491 here, for conciseness.
6494 Similar to @code{bag-emerged}, but this time including all the bootstrap
6497 @item bag-with-origins
6498 Similar to @code{bag}, but also showing origins and their dependencies.
6501 This is the most detailed representation: It shows the DAG of
6502 derivations (@pxref{Derivations}) and plain store items. Compared to
6503 the above representation, many additional nodes are visible, including
6504 build scripts, patches, Guile modules, etc.
6506 For this type of graph, it is also possible to pass a @file{.drv} file
6507 name instead of a package name, as in:
6510 guix graph -t derivation `guix system build -d my-config.scm`
6514 All the types above correspond to @emph{build-time dependencies}. The
6515 following graph type represents the @emph{run-time dependencies}:
6519 This is the graph of @dfn{references} of a package output, as returned
6520 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6522 If the given package output is not available in the store, @command{guix
6523 graph} attempts to obtain dependency information from substitutes.
6525 Here you can also pass a store file name instead of a package name. For
6526 example, the command below produces the reference graph of your profile
6527 (which can be big!):
6530 guix graph -t references `readlink -f ~/.guix-profile`
6534 This is the graph of the @dfn{referrers} of a store item, as returned by
6535 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6537 This relies exclusively on local information from your store. For
6538 instance, let us suppose that the current Inkscape is available in 10
6539 profiles on your machine; @command{guix graph -t referrers inkscape}
6540 will show a graph rooted at Inkscape and with those 10 profiles linked
6543 It can help determine what is preventing a store item from being garbage
6548 The available options are the following:
6551 @item --type=@var{type}
6552 @itemx -t @var{type}
6553 Produce a graph output of @var{type}, where @var{type} must be one of
6554 the values listed above.
6557 List the supported graph types.
6559 @item --backend=@var{backend}
6560 @itemx -b @var{backend}
6561 Produce a graph using the selected @var{backend}.
6563 @item --list-backends
6564 List the supported graph backends.
6566 Currently, the available backends are Graphviz and d3.js.
6568 @item --expression=@var{expr}
6569 @itemx -e @var{expr}
6570 Consider the package @var{expr} evaluates to.
6572 This is useful to precisely refer to a package, as in this example:
6575 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6580 @node Invoking guix environment
6581 @section Invoking @command{guix environment}
6583 @cindex reproducible build environments
6584 @cindex development environments
6585 @cindex @command{guix environment}
6586 @cindex environment, package build environment
6587 The purpose of @command{guix environment} is to assist hackers in
6588 creating reproducible development environments without polluting their
6589 package profile. The @command{guix environment} tool takes one or more
6590 packages, builds all of their inputs, and creates a shell
6591 environment to use them.
6593 The general syntax is:
6596 guix environment @var{options} @var{package}@dots{}
6599 The following example spawns a new shell set up for the development of
6603 guix environment guile
6606 If the needed dependencies are not built yet, @command{guix environment}
6607 automatically builds them. The environment of the new shell is an augmented
6608 version of the environment that @command{guix environment} was run in.
6609 It contains the necessary search paths for building the given package
6610 added to the existing environment variables. To create a ``pure''
6611 environment, in which the original environment variables have been unset,
6612 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6613 environment variables such as @code{PATH} in their @file{~/.bashrc}
6614 file. As a consequence, when @code{guix environment} launches it, Bash
6615 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6616 environment variables. It is an error to define such environment
6617 variables in @file{.bashrc}; instead, they should be defined in
6618 @file{.bash_profile}, which is sourced only by log-in shells.
6619 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6620 details on Bash start-up files.}.
6622 @vindex GUIX_ENVIRONMENT
6623 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6624 variable in the shell it spawns; its value is the file name of the
6625 profile of this environment. This allows users to, say, define a
6626 specific prompt for development environments in their @file{.bashrc}
6627 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6630 if [ -n "$GUIX_ENVIRONMENT" ]
6632 export PS1="\u@@\h \w [dev]\$ "
6637 ... or to browse the profile:
6640 $ ls "$GUIX_ENVIRONMENT/bin"
6643 Additionally, more than one package may be specified, in which case the
6644 union of the inputs for the given packages are used. For example, the
6645 command below spawns a shell where all of the dependencies of both Guile
6646 and Emacs are available:
6649 guix environment guile emacs
6652 Sometimes an interactive shell session is not desired. An arbitrary
6653 command may be invoked by placing the @code{--} token to separate the
6654 command from the rest of the arguments:
6657 guix environment guile -- make -j4
6660 In other situations, it is more convenient to specify the list of
6661 packages needed in the environment. For example, the following command
6662 runs @command{python} from an environment containing Python@tie{}2.7 and
6666 guix environment --ad-hoc python2-numpy python-2.7 -- python
6669 Furthermore, one might want the dependencies of a package and also some
6670 additional packages that are not build-time or runtime dependencies, but
6671 are useful when developing nonetheless. Because of this, the
6672 @code{--ad-hoc} flag is positional. Packages appearing before
6673 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6674 added to the environment. Packages appearing after are interpreted as
6675 packages that will be added to the environment directly. For example,
6676 the following command creates a Guix development environment that
6677 additionally includes Git and strace:
6680 guix environment guix --ad-hoc git strace
6683 Sometimes it is desirable to isolate the environment as much as
6684 possible, for maximal purity and reproducibility. In particular, when
6685 using Guix on a host distro that is not GuixSD, it is desirable to
6686 prevent access to @file{/usr/bin} and other system-wide resources from
6687 the development environment. For example, the following command spawns
6688 a Guile REPL in a ``container'' where only the store and the current
6689 working directory are mounted:
6692 guix environment --ad-hoc --container guile -- guile
6696 The @code{--container} option requires Linux-libre 3.19 or newer.
6699 The available options are summarized below.
6702 @item --root=@var{file}
6703 @itemx -r @var{file}
6704 @cindex persistent environment
6705 @cindex garbage collector root, for environments
6706 Make @var{file} a symlink to the profile for this environment, and
6707 register it as a garbage collector root.
6709 This is useful if you want to protect your environment from garbage
6710 collection, to make it ``persistent''.
6712 When this option is omitted, the environment is protected from garbage
6713 collection only for the duration of the @command{guix environment}
6714 session. This means that next time you recreate the same environment,
6715 you could have to rebuild or re-download packages.
6717 @item --expression=@var{expr}
6718 @itemx -e @var{expr}
6719 Create an environment for the package or list of packages that
6720 @var{expr} evaluates to.
6722 For example, running:
6725 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6728 starts a shell with the environment for this specific variant of the
6734 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6737 starts a shell with all the GuixSD base packages available.
6739 The above commands only use the default output of the given packages.
6740 To select other outputs, two element tuples can be specified:
6743 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6746 @item --load=@var{file}
6747 @itemx -l @var{file}
6748 Create an environment for the package or list of packages that the code
6749 within @var{file} evaluates to.
6751 As an example, @var{file} might contain a definition like this
6752 (@pxref{Defining Packages}):
6755 @verbatiminclude environment-gdb.scm
6759 Include all specified packages in the resulting environment, as if an
6760 @i{ad hoc} package were defined with them as inputs. This option is
6761 useful for quickly creating an environment without having to write a
6762 package expression to contain the desired inputs.
6764 For instance, the command:
6767 guix environment --ad-hoc guile guile-sdl -- guile
6770 runs @command{guile} in an environment where Guile and Guile-SDL are
6773 Note that this example implicitly asks for the default output of
6774 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6775 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6776 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6778 This option may be composed with the default behavior of @command{guix
6779 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6780 as packages whose dependencies will be added to the environment, the
6781 default behavior. Packages appearing after are interpreted as packages
6782 that will be added to the environment directly.
6785 Unset existing environment variables when building the new environment.
6786 This has the effect of creating an environment in which search paths
6787 only contain package inputs.
6789 @item --search-paths
6790 Display the environment variable definitions that make up the
6793 @item --system=@var{system}
6794 @itemx -s @var{system}
6795 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6800 Run @var{command} within an isolated container. The current working
6801 directory outside the container is mapped inside the container.
6802 Additionally, a dummy home directory is created that matches the current
6803 user's home directory, and @file{/etc/passwd} is configured accordingly.
6804 The spawned process runs as the current user outside the container, but
6805 has root privileges in the context of the container.
6809 For containers, share the network namespace with the host system.
6810 Containers created without this flag only have access to the loopback
6813 @item --expose=@var{source}[=@var{target}]
6814 For containers, expose the file system @var{source} from the host system
6815 as the read-only file system @var{target} within the container. If
6816 @var{target} is not specified, @var{source} is used as the target mount
6817 point in the container.
6819 The example below spawns a Guile REPL in a container in which the user's
6820 home directory is accessible read-only via the @file{/exchange}
6824 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6827 @item --share=@var{source}[=@var{target}]
6828 For containers, share the file system @var{source} from the host system
6829 as the writable file system @var{target} within the container. If
6830 @var{target} is not specified, @var{source} is used as the target mount
6831 point in the container.
6833 The example below spawns a Guile REPL in a container in which the user's
6834 home directory is accessible for both reading and writing via the
6835 @file{/exchange} directory:
6838 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6842 @command{guix environment}
6843 also supports all of the common build options that @command{guix
6844 build} supports (@pxref{Common Build Options}).
6847 @node Invoking guix publish
6848 @section Invoking @command{guix publish}
6850 @cindex @command{guix publish}
6851 The purpose of @command{guix publish} is to enable users to easily share
6852 their store with others, who can then use it as a substitute server
6853 (@pxref{Substitutes}).
6855 When @command{guix publish} runs, it spawns an HTTP server which allows
6856 anyone with network access to obtain substitutes from it. This means
6857 that any machine running Guix can also act as if it were a build farm,
6858 since the HTTP interface is compatible with Hydra, the software behind
6859 the @code{hydra.gnu.org} build farm.
6861 For security, each substitute is signed, allowing recipients to check
6862 their authenticity and integrity (@pxref{Substitutes}). Because
6863 @command{guix publish} uses the signing key of the system, which is only
6864 readable by the system administrator, it must be started as root; the
6865 @code{--user} option makes it drop root privileges early on.
6867 The signing key pair must be generated before @command{guix publish} is
6868 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6871 The general syntax is:
6874 guix publish @var{options}@dots{}
6877 Running @command{guix publish} without any additional arguments will
6878 spawn an HTTP server on port 8080:
6884 Once a publishing server has been authorized (@pxref{Invoking guix
6885 archive}), the daemon may download substitutes from it:
6888 guix-daemon --substitute-urls=http://example.org:8080
6891 By default, @command{guix publish} compresses archives on the fly as it
6892 serves them. This ``on-the-fly'' mode is convenient in that it requires
6893 no setup and is immediately available. However, when serving lots of
6894 clients, we recommend using the @option{--cache} option, which enables
6895 caching of the archives before they are sent to clients---see below for
6896 details. The @command{guix weather} command provides a handy way to
6897 check what a server provides (@pxref{Invoking guix weather}).
6899 As a bonus, @command{guix publish} also serves as a content-addressed
6900 mirror for source files referenced in @code{origin} records
6901 (@pxref{origin Reference}). For instance, assuming @command{guix
6902 publish} is running on @code{example.org}, the following URL returns the
6903 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6904 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6907 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6910 Obviously, these URLs only work for files that are in the store; in
6911 other cases, they return 404 (``Not Found'').
6913 The following options are available:
6916 @item --port=@var{port}
6917 @itemx -p @var{port}
6918 Listen for HTTP requests on @var{port}.
6920 @item --listen=@var{host}
6921 Listen on the network interface for @var{host}. The default is to
6922 accept connections from any interface.
6924 @item --user=@var{user}
6925 @itemx -u @var{user}
6926 Change privileges to @var{user} as soon as possible---i.e., once the
6927 server socket is open and the signing key has been read.
6929 @item --compression[=@var{level}]
6930 @itemx -C [@var{level}]
6931 Compress data using the given @var{level}. When @var{level} is zero,
6932 disable compression. The range 1 to 9 corresponds to different gzip
6933 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6936 Unless @option{--cache} is used, compression occurs on the fly and
6937 the compressed streams are not
6938 cached. Thus, to reduce load on the machine that runs @command{guix
6939 publish}, it may be a good idea to choose a low compression level, to
6940 run @command{guix publish} behind a caching proxy, or to use
6941 @option{--cache}. Using @option{--cache} has the advantage that it
6942 allows @command{guix publish} to add @code{Content-Length} HTTP header
6945 @item --cache=@var{directory}
6946 @itemx -c @var{directory}
6947 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6948 and only serve archives that are in cache.
6950 When this option is omitted, archives and meta-data are created
6951 on-the-fly. This can reduce the available bandwidth, especially when
6952 compression is enabled, since this may become CPU-bound. Another
6953 drawback of the default mode is that the length of archives is not known
6954 in advance, so @command{guix publish} does not add a
6955 @code{Content-Length} HTTP header to its responses, which in turn
6956 prevents clients from knowing the amount of data being downloaded.
6958 Conversely, when @option{--cache} is used, the first request for a store
6959 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6960 background process to @dfn{bake} the archive---computing its
6961 @code{.narinfo} and compressing the archive, if needed. Once the
6962 archive is cached in @var{directory}, subsequent requests succeed and
6963 are served directly from the cache, which guarantees that clients get
6964 the best possible bandwidth.
6966 The ``baking'' process is performed by worker threads. By default, one
6967 thread per CPU core is created, but this can be customized. See
6968 @option{--workers} below.
6970 When @option{--ttl} is used, cached entries are automatically deleted
6971 when they have expired.
6973 @item --workers=@var{N}
6974 When @option{--cache} is used, request the allocation of @var{N} worker
6975 threads to ``bake'' archives.
6977 @item --ttl=@var{ttl}
6978 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6979 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6980 days, @code{1m} means 1 month, and so on.
6982 This allows the user's Guix to keep substitute information in cache for
6983 @var{ttl}. However, note that @code{guix publish} does not itself
6984 guarantee that the store items it provides will indeed remain available
6985 for as long as @var{ttl}.
6987 Additionally, when @option{--cache} is used, cached entries that have
6988 not been accessed for @var{ttl} and that no longer have a corresponding
6989 item in the store, may be deleted.
6991 @item --nar-path=@var{path}
6992 Use @var{path} as the prefix for the URLs of ``nar'' files
6993 (@pxref{Invoking guix archive, normalized archives}).
6995 By default, nars are served at a URL such as
6996 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6997 change the @code{/nar} part to @var{path}.
6999 @item --public-key=@var{file}
7000 @itemx --private-key=@var{file}
7001 Use the specific @var{file}s as the public/private key pair used to sign
7002 the store items being published.
7004 The files must correspond to the same key pair (the private key is used
7005 for signing and the public key is merely advertised in the signature
7006 metadata). They must contain keys in the canonical s-expression format
7007 as produced by @command{guix archive --generate-key} (@pxref{Invoking
7008 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
7009 @file{/etc/guix/signing-key.sec} are used.
7011 @item --repl[=@var{port}]
7012 @itemx -r [@var{port}]
7013 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
7014 Reference Manual}) on @var{port} (37146 by default). This is used
7015 primarily for debugging a running @command{guix publish} server.
7018 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
7019 instantiate a @code{guix-publish-service-type} service in the @code{services} field
7020 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
7021 @code{guix-publish-service-type}}).
7023 If you are instead running Guix on a ``foreign distro'', follow these
7028 If your host distro uses the systemd init system:
7031 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
7032 /etc/systemd/system/
7033 # systemctl start guix-publish && systemctl enable guix-publish
7037 If your host distro uses the Upstart init system:
7040 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
7041 # start guix-publish
7045 Otherwise, proceed similarly with your distro's init system.
7048 @node Invoking guix challenge
7049 @section Invoking @command{guix challenge}
7051 @cindex reproducible builds
7052 @cindex verifiable builds
7053 @cindex @command{guix challenge}
7055 Do the binaries provided by this server really correspond to the source
7056 code it claims to build? Is a package build process deterministic?
7057 These are the questions the @command{guix challenge} command attempts to
7060 The former is obviously an important question: Before using a substitute
7061 server (@pxref{Substitutes}), one had better @emph{verify} that it
7062 provides the right binaries, and thus @emph{challenge} it. The latter
7063 is what enables the former: If package builds are deterministic, then
7064 independent builds of the package should yield the exact same result,
7065 bit for bit; if a server provides a binary different from the one
7066 obtained locally, it may be either corrupt or malicious.
7068 We know that the hash that shows up in @file{/gnu/store} file names is
7069 the hash of all the inputs of the process that built the file or
7070 directory---compilers, libraries, build scripts,
7071 etc. (@pxref{Introduction}). Assuming deterministic build processes,
7072 one store file name should map to exactly one build output.
7073 @command{guix challenge} checks whether there is, indeed, a single
7074 mapping by comparing the build outputs of several independent builds of
7075 any given store item.
7077 The command output looks like this:
7080 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
7081 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
7082 updating list of substitutes from 'https://guix.example.org'... 100.0%
7083 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
7084 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7085 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7086 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
7087 /gnu/store/@dots{}-git-2.5.0 contents differ:
7088 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
7089 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
7090 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
7091 /gnu/store/@dots{}-pius-2.1.1 contents differ:
7092 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7093 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7094 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
7098 In this example, @command{guix challenge} first scans the store to
7099 determine the set of locally-built derivations---as opposed to store
7100 items that were downloaded from a substitute server---and then queries
7101 all the substitute servers. It then reports those store items for which
7102 the servers obtained a result different from the local build.
7104 @cindex non-determinism, in package builds
7105 As an example, @code{guix.example.org} always gets a different answer.
7106 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7107 case of Git. This might indicate that the build process of Git is
7108 non-deterministic, meaning that its output varies as a function of
7109 various things that Guix does not fully control, in spite of building
7110 packages in isolated environments (@pxref{Features}). Most common
7111 sources of non-determinism include the addition of timestamps in build
7112 results, the inclusion of random numbers, and directory listings sorted
7113 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7116 To find out what is wrong with this Git binary, we can do something along
7117 these lines (@pxref{Invoking guix archive}):
7120 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7121 | guix archive -x /tmp/git
7122 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7125 This command shows the difference between the files resulting from the
7126 local build, and the files resulting from the build on
7127 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7128 diffutils, Comparing and Merging Files}). The @command{diff} command
7129 works great for text files. When binary files differ, a better option
7130 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7131 visualize differences for all kinds of files.
7133 Once you have done that work, you can tell whether the differences are due
7134 to a non-deterministic build process or to a malicious server. We try
7135 hard to remove sources of non-determinism in packages to make it easier
7136 to verify substitutes, but of course, this is a process that
7137 involves not just Guix, but a large part of the free software community.
7138 In the meantime, @command{guix challenge} is one tool to help address
7141 If you are writing packages for Guix, you are encouraged to check
7142 whether @code{hydra.gnu.org} and other substitute servers obtain the
7143 same build result as you did with:
7146 $ guix challenge @var{package}
7150 where @var{package} is a package specification such as
7151 @code{guile@@2.0} or @code{glibc:debug}.
7153 The general syntax is:
7156 guix challenge @var{options} [@var{packages}@dots{}]
7159 When a difference is found between the hash of a locally-built item and
7160 that of a server-provided substitute, or among substitutes provided by
7161 different servers, the command displays it as in the example above and
7162 its exit code is 2 (other non-zero exit codes denote other kinds of
7165 The one option that matters is:
7169 @item --substitute-urls=@var{urls}
7170 Consider @var{urls} the whitespace-separated list of substitute source
7175 Show details about matches (identical contents) in addition to
7176 information about mismatches.
7180 @node Invoking guix copy
7181 @section Invoking @command{guix copy}
7183 @cindex copy, of store items, over SSH
7184 @cindex SSH, copy of store items
7185 @cindex sharing store items across machines
7186 @cindex transferring store items across machines
7187 The @command{guix copy} command copies items from the store of one
7188 machine to that of another machine over a secure shell (SSH)
7189 connection@footnote{This command is available only when Guile-SSH was
7190 found. @xref{Requirements}, for details.}. For example, the following
7191 command copies the @code{coreutils} package, the user's profile, and all
7192 their dependencies over to @var{host}, logged in as @var{user}:
7195 guix copy --to=@var{user}@@@var{host} \
7196 coreutils `readlink -f ~/.guix-profile`
7199 If some of the items to be copied are already present on @var{host},
7200 they are not actually sent.
7202 The command below retrieves @code{libreoffice} and @code{gimp} from
7203 @var{host}, assuming they are available there:
7206 guix copy --from=@var{host} libreoffice gimp
7209 The SSH connection is established using the Guile-SSH client, which is
7210 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7211 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7213 The key used to sign items that are sent must be accepted by the remote
7214 machine. Likewise, the key used by the remote machine to sign items you
7215 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7216 own daemon. @xref{Invoking guix archive}, for more information about
7217 store item authentication.
7219 The general syntax is:
7222 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7225 You must always specify one of the following options:
7228 @item --to=@var{spec}
7229 @itemx --from=@var{spec}
7230 Specify the host to send to or receive from. @var{spec} must be an SSH
7231 spec such as @code{example.org}, @code{charlie@@example.org}, or
7232 @code{charlie@@example.org:2222}.
7235 The @var{items} can be either package names, such as @code{gimp}, or
7236 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7238 When specifying the name of a package to send, it is first built if
7239 needed, unless @option{--dry-run} was specified. Common build options
7240 are supported (@pxref{Common Build Options}).
7243 @node Invoking guix container
7244 @section Invoking @command{guix container}
7246 @cindex @command{guix container}
7248 As of version @value{VERSION}, this tool is experimental. The interface
7249 is subject to radical change in the future.
7252 The purpose of @command{guix container} is to manipulate processes
7253 running within an isolated environment, commonly known as a
7254 ``container'', typically created by the @command{guix environment}
7255 (@pxref{Invoking guix environment}) and @command{guix system container}
7256 (@pxref{Invoking guix system}) commands.
7258 The general syntax is:
7261 guix container @var{action} @var{options}@dots{}
7264 @var{action} specifies the operation to perform with a container, and
7265 @var{options} specifies the context-specific arguments for the action.
7267 The following actions are available:
7271 Execute a command within the context of a running container.
7276 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7279 @var{pid} specifies the process ID of the running container.
7280 @var{program} specifies an executable file name within the root file
7281 system of the container. @var{arguments} are the additional options that
7282 will be passed to @var{program}.
7284 The following command launches an interactive login shell inside a
7285 GuixSD container, started by @command{guix system container}, and whose
7289 guix container exec 9001 /run/current-system/profile/bin/bash --login
7292 Note that the @var{pid} cannot be the parent process of a container. It
7293 must be PID 1 of the container or one of its child processes.
7297 @node Invoking guix weather
7298 @section Invoking @command{guix weather}
7300 Occasionally you're grumpy because substitutes are lacking and you end
7301 up building packages by yourself (@pxref{Substitutes}). The
7302 @command{guix weather} command reports on substitute availability on the
7303 specified servers so you can have an idea of whether you'll be grumpy
7304 today. It can sometimes be useful info as a user, but it is primarily
7305 useful to people running @command{guix publish} (@pxref{Invoking guix
7308 @cindex statistics, for substitutes
7309 @cindex availability of substitutes
7310 @cindex substitute availability
7311 @cindex weather, substitute availability
7312 Here's a sample run:
7315 $ guix weather --substitute-urls=https://guix.example.org
7316 computing 5,872 package derivations for x86_64-linux...
7317 looking for 6,128 store items on https://guix.example.org..
7318 updating list of substitutes from 'https://guix.example.org'... 100.0%
7319 https://guix.example.org
7320 43.4% substitutes available (2,658 out of 6,128)
7321 7,032.5 MiB of nars (compressed)
7322 19,824.2 MiB on disk (uncompressed)
7323 0.030 seconds per request (182.9 seconds in total)
7324 33.5 requests per second
7327 As you can see, it reports the fraction of all the packages for which
7328 substitutes are available on the server---regardless of whether
7329 substitutes are enabled, and regardless of whether this server's signing
7330 key is authorized. It also reports the size of the compressed archives
7331 (``nars'') provided by the server, the size the corresponding store
7332 items occupy in the store (assuming deduplication is turned off), and
7333 the server's throughput.
7335 To achieve that, @command{guix weather} queries over HTTP(S) meta-data
7336 (@dfn{narinfos}) for all the relevant store items. Like @command{guix
7337 challenge}, it ignores signatures on those substitutes, which is
7338 innocuous since the command only gathers statistics and cannot install
7341 Among other things, it is possible to query specific system types and
7342 specific package sets. The available options are listed below.
7345 @item --substitute-urls=@var{urls}
7346 @var{urls} is the space-separated list of substitute server URLs to
7347 query. When this option is omitted, the default set of substitute
7350 @item --system=@var{system}
7351 @itemx -s @var{system}
7352 Query substitutes for @var{system}---e.g., @code{aarch64-linux}. This
7353 option can be repeated, in which case @command{guix weather} will query
7354 substitutes for several system types.
7356 @item --manifest=@var{file}
7357 Instead of querying substitutes for all the packages, only ask for those
7358 specified in @var{file}. @var{file} must contain a @dfn{manifest}, as
7359 with the @code{-m} option of @command{guix package} (@pxref{Invoking
7364 @c *********************************************************************
7365 @node GNU Distribution
7366 @chapter GNU Distribution
7368 @cindex Guix System Distribution
7370 Guix comes with a distribution of the GNU system consisting entirely of
7371 free software@footnote{The term ``free'' here refers to the
7372 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7373 users of that software}.}. The
7374 distribution can be installed on its own (@pxref{System Installation}),
7375 but it is also possible to install Guix as a package manager on top of
7376 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7377 between the two, we refer to the standalone distribution as the Guix
7378 System Distribution, or GuixSD.
7380 The distribution provides core GNU packages such as GNU libc, GCC, and
7381 Binutils, as well as many GNU and non-GNU applications. The complete
7382 list of available packages can be browsed
7383 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7384 running @command{guix package} (@pxref{Invoking guix package}):
7387 guix package --list-available
7390 Our goal is to provide a practical 100% free software distribution of
7391 Linux-based and other variants of GNU, with a focus on the promotion and
7392 tight integration of GNU components, and an emphasis on programs and
7393 tools that help users exert that freedom.
7395 Packages are currently available on the following platforms:
7400 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7403 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7406 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7407 using the EABI hard-float application binary interface (ABI),
7408 and Linux-Libre kernel.
7411 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7412 currently in an experimental stage, with limited support.
7413 @xref{Contributing}, for how to help!
7415 @item mips64el-linux
7416 little-endian 64-bit MIPS processors, specifically the Loongson series,
7417 n32 ABI, and Linux-Libre kernel.
7421 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7424 For information on porting to other architectures or kernels,
7428 * System Installation:: Installing the whole operating system.
7429 * System Configuration:: Configuring the operating system.
7430 * Documentation:: Browsing software user manuals.
7431 * Installing Debugging Files:: Feeding the debugger.
7432 * Security Updates:: Deploying security fixes quickly.
7433 * Package Modules:: Packages from the programmer's viewpoint.
7434 * Packaging Guidelines:: Growing the distribution.
7435 * Bootstrapping:: GNU/Linux built from scratch.
7436 * Porting:: Targeting another platform or kernel.
7439 Building this distribution is a cooperative effort, and you are invited
7440 to join! @xref{Contributing}, for information about how you can help.
7442 @node System Installation
7443 @section System Installation
7445 @cindex installing GuixSD
7446 @cindex Guix System Distribution
7447 This section explains how to install the Guix System Distribution (GuixSD)
7448 on a machine. The Guix package manager can
7449 also be installed on top of a running GNU/Linux system,
7450 @pxref{Installation}.
7454 @c This paragraph is for people reading this from tty2 of the
7455 @c installation image.
7456 You are reading this documentation with an Info reader. For details on
7457 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7458 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7459 Info}. Hit @kbd{l} afterwards to come back here.
7461 Alternately, run @command{info info} in another tty to keep the manual
7467 * Limitations:: What you can expect.
7468 * Hardware Considerations:: Supported hardware.
7469 * USB Stick Installation:: Preparing the installation medium.
7470 * DVD Installation:: Preparing the installation medium.
7471 * Preparing for Installation:: Networking, partitioning, etc.
7472 * Proceeding with the Installation:: The real thing.
7473 * Installing GuixSD in a VM:: GuixSD playground.
7474 * Building the Installation Image:: How this comes to be.
7478 @subsection Limitations
7480 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7481 not production-ready. It may contain bugs and lack important
7482 features. Thus, if you are looking for a stable production system that
7483 respects your freedom as a computer user, a good solution at this point
7484 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7485 the more established GNU/Linux distributions}. We hope you can soon switch
7486 to the GuixSD without fear, of course. In the meantime, you can
7487 also keep using your distribution and try out the package manager on top
7488 of it (@pxref{Installation}).
7490 Before you proceed with the installation, be aware of the following
7491 noteworthy limitations applicable to version @value{VERSION}:
7495 The installation process does not include a graphical user interface and
7496 requires familiarity with GNU/Linux (see the following subsections to
7497 get a feel of what that means.)
7500 Support for the Logical Volume Manager (LVM) is missing.
7503 More and more system services are provided (@pxref{Services}), but some
7507 More than 5,300 packages are available, but you may
7508 occasionally find that a useful package is missing.
7511 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7512 as well as a number of X11 window managers. However, some graphical
7513 applications may be missing, as well as KDE.
7516 You have been warned! But more than a disclaimer, this is an invitation
7517 to report issues (and success stories!), and to join us in improving it.
7518 @xref{Contributing}, for more info.
7521 @node Hardware Considerations
7522 @subsection Hardware Considerations
7524 @cindex hardware support on GuixSD
7525 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7526 builds around the kernel Linux-libre, which means that only hardware for
7527 which free software drivers and firmware exist is supported. Nowadays,
7528 a wide range of off-the-shelf hardware is supported on
7529 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7530 Ethernet controllers. Unfortunately, there are still areas where
7531 hardware vendors deny users control over their own computing, and such
7532 hardware is not supported on GuixSD.
7534 @cindex WiFi, hardware support
7535 One of the main areas where free drivers or firmware are lacking is WiFi
7536 devices. WiFi devices known to work include those using Atheros chips
7537 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7538 driver, and those using Broadcom/AirForce chips (BCM43xx with
7539 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7540 Linux-libre driver. Free firmware exists for both and is available
7541 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7542 (@pxref{operating-system Reference, @code{firmware}}).
7544 @cindex RYF, Respects Your Freedom
7545 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7546 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7547 certification program for hardware products that respect your freedom
7548 and your privacy and ensure that you have control over your device. We
7549 encourage you to check the list of RYF-certified devices.
7551 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7552 web site. It contains a catalog of hardware devices with information
7553 about their support in GNU/Linux.
7556 @node USB Stick Installation
7557 @subsection USB Stick Installation
7559 An installation image for USB sticks can be downloaded from
7560 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz},
7561 where @var{system} is one of:
7565 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7568 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7571 @c start duplication of authentication part from ``Binary Installation''
7572 Make sure to download the associated @file{.sig} file and to verify the
7573 authenticity of the image against it, along these lines:
7576 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz.sig
7577 $ gpg --verify guixsd-install-@value{VERSION}.@var{system}.xz.sig
7580 If that command fails because you do not have the required public key,
7581 then run this command to import it:
7584 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7588 and rerun the @code{gpg --verify} command.
7591 This image contains the tools necessary for an installation.
7592 It is meant to be copied @emph{as is} to a large-enough USB stick or DVD.
7594 To copy the image to a USB stick, follow these steps:
7598 Decompress the image using the @command{xz} command:
7601 xz -d guixsd-install-@value{VERSION}.@var{system}.xz
7605 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7606 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7607 copy the image with:
7610 dd if=guixsd-install-@value{VERSION}.x86_64 of=/dev/sdX
7614 Access to @file{/dev/sdX} usually requires root privileges.
7617 Once this is done, you should be able to reboot the system and boot from
7618 the USB stick. The latter usually requires you to get in the BIOS or
7619 UEFI boot menu, where you can choose to boot from the USB stick.
7621 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7622 GuixSD in a virtual machine (VM).
7624 @node DVD Installation
7625 @subsection DVD Installation
7627 An installation image for DVDs can be downloaded from
7628 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz},
7629 where @var{system} is one of:
7633 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7636 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7639 @c start duplication of authentication part from ``Binary Installation''
7640 Make sure to download the associated @file{.sig} file and to verify the
7641 authenticity of the image against it, along these lines:
7644 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz.sig
7645 $ gpg --verify guixsd-install-@value{VERSION}.@var{system}.xz.sig
7648 If that command fails because you do not have the required public key,
7649 then run this command to import it:
7652 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7656 and rerun the @code{gpg --verify} command.
7659 This image contains the tools necessary for an installation.
7660 It is meant to be copied @emph{as is} to a large-enough USB stick or DVD.
7662 To copy the image to a DVD, follow these steps:
7666 Decompress the image using the @command{xz} command:
7669 xz -d guixsd-install-@value{VERSION}.@var{system}.xz
7673 Insert a blank DVD into your machine, and determine
7674 its device name. Assuming that the DVD drive is known as @file{/dev/srX},
7675 copy the image with:
7678 growisofs -dvd-compat -Z /dev/srX=guixsd-install-@value{VERSION}.x86_64
7681 Access to @file{/dev/srX} usually requires root privileges.
7684 Once this is done, you should be able to reboot the system and boot from
7685 the DVD. The latter usually requires you to get in the BIOS or
7686 UEFI boot menu, where you can choose to boot from the DVD.
7688 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7689 GuixSD in a virtual machine (VM).
7691 @node Preparing for Installation
7692 @subsection Preparing for Installation
7694 Once you have successfully booted your computer using the installation medium,
7695 you should end up with a root prompt. Several console TTYs are configured
7696 and can be used to run commands as root. TTY2 shows this documentation,
7697 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7698 Stand-alone GNU Info}). The installation system runs the GPM mouse
7699 daemon, which allows you to select text with the left mouse button and
7700 to paste it with the middle button.
7703 Installation requires access to the Internet so that any missing
7704 dependencies of your system configuration can be downloaded. See the
7705 ``Networking'' section below.
7708 The installation system includes many common tools needed for this task.
7709 But it is also a full-blown GuixSD system, which means that you can
7710 install additional packages, should you need it, using @command{guix
7711 package} (@pxref{Invoking guix package}).
7713 @subsubsection Keyboard Layout
7715 @cindex keyboard layout
7716 The installation image uses the US qwerty keyboard layout. If you want
7717 to change it, you can use the @command{loadkeys} command. For example,
7718 the following command selects the Dvorak keyboard layout:
7724 See the files under @file{/run/current-system/profile/share/keymaps} for
7725 a list of available keyboard layouts. Run @command{man loadkeys} for
7728 @subsubsection Networking
7730 Run the following command see what your network interfaces are called:
7737 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7743 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7744 Wired interfaces have a name starting with @samp{e}; for example, the
7745 interface corresponding to the first on-board Ethernet controller is
7746 called @samp{eno1}. Wireless interfaces have a name starting with
7747 @samp{w}, like @samp{w1p2s0}.
7750 @item Wired connection
7751 To configure a wired network run the following command, substituting
7752 @var{interface} with the name of the wired interface you want to use.
7755 ifconfig @var{interface} up
7758 @item Wireless connection
7761 To configure wireless networking, you can create a configuration file
7762 for the @command{wpa_supplicant} configuration tool (its location is not
7763 important) using one of the available text editors such as
7767 zile wpa_supplicant.conf
7770 As an example, the following stanza can go to this file and will work
7771 for many wireless networks, provided you give the actual SSID and
7772 passphrase for the network you are connecting to:
7776 ssid="@var{my-ssid}"
7778 psk="the network's secret passphrase"
7782 Start the wireless service and run it in the background with the
7783 following command (substitute @var{interface} with the name of the
7784 network interface you want to use):
7787 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7790 Run @command{man wpa_supplicant} for more information.
7794 At this point, you need to acquire an IP address. On a network where IP
7795 addresses are automatically assigned @i{via} DHCP, you can run:
7798 dhclient -v @var{interface}
7801 Try to ping a server to see if networking is up and running:
7807 Setting up network access is almost always a requirement because the
7808 image does not contain all the software and tools that may be needed.
7810 @cindex installing over SSH
7811 If you want to, you can continue the installation remotely by starting
7815 herd start ssh-daemon
7818 Make sure to either set a password with @command{passwd}, or configure
7819 OpenSSH public key authentication before logging in.
7821 @subsubsection Disk Partitioning
7823 Unless this has already been done, the next step is to partition, and
7824 then format the target partition(s).
7826 The installation image includes several partitioning tools, including
7827 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7828 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7829 the partition layout you want:
7835 If your disk uses the GUID Partition Table (GPT) format and you plan to
7836 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7837 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7840 @cindex EFI, installation
7841 @cindex UEFI, installation
7842 @cindex ESP, EFI system partition
7843 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7844 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7845 must have the @code{esp} flag set. E.g., for @command{parted}:
7848 parted /dev/sda set 1 esp on
7851 Once you are done partitioning the target hard disk drive, you have to
7852 create a file system on the relevant partition(s)@footnote{Currently
7853 GuixSD only supports ext4 and btrfs file systems. In particular, code
7854 that reads partition UUIDs and labels only works for these file system
7857 Preferably, assign partitions a label so that you can easily and
7858 reliably refer to them in @code{file-system} declarations (@pxref{File
7859 Systems}). This is typically done using the @code{-L} option of
7860 @command{mkfs.ext4} and related commands. So, assuming the target root
7861 partition lives at @file{/dev/sda1}, a file system with the label
7862 @code{my-root} can be created with:
7865 mkfs.ext4 -L my-root /dev/sda1
7868 @cindex encrypted disk
7869 If you are instead planning to encrypt the root partition, you can use
7870 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7871 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7872 @code{man cryptsetup}} for more information.) Assuming you want to
7873 store the root partition on @file{/dev/sda1}, the command sequence would
7874 be along these lines:
7877 cryptsetup luksFormat /dev/sda1
7878 cryptsetup open --type luks /dev/sda1 my-partition
7879 mkfs.ext4 -L my-root /dev/mapper/my-partition
7882 Once that is done, mount the target root partition under @file{/mnt}
7883 with a command like (again, assuming @code{my-root} is the label of the
7887 mount LABEL=my-root /mnt
7890 Also mount any other partitions you would like to use on the target
7891 system relative to this path. If you have @file{/boot} on a separate
7892 partition for example, mount it at @file{/mnt/boot} now so it is found
7893 by @code{guix system init} afterwards.
7895 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7896 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7897 sure to initialize them with @command{mkswap}. Assuming you have one
7898 swap partition on @file{/dev/sda2}, you would run:
7905 Alternatively, you may use a swap file. For example, assuming that in
7906 the new system you want to use the file @file{/swapfile} as a swap file,
7907 you would run@footnote{This example will work for many types of file
7908 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7909 btrfs), the required steps may be different. For details, see the
7910 manual pages for @command{mkswap} and @command{swapon}.}:
7913 # This is 10 GiB of swap space. Adjust "count" to change the size.
7914 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7915 # For security, make the file readable and writable only by root.
7916 chmod 600 /mnt/swapfile
7917 mkswap /mnt/swapfile
7918 swapon /mnt/swapfile
7921 Note that if you have encrypted the root partition and created a swap
7922 file in its file system as described above, then the encryption also
7923 protects the swap file, just like any other file in that file system.
7925 @node Proceeding with the Installation
7926 @subsection Proceeding with the Installation
7928 With the target partitions ready and the target root mounted on
7929 @file{/mnt}, we're ready to go. First, run:
7932 herd start cow-store /mnt
7935 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7936 during the installation phase are written to the target disk on @file{/mnt}
7937 rather than kept in memory. This is necessary because the first phase of
7938 the @command{guix system init} command (see below) entails downloads or
7939 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7941 Next, you have to edit a file and
7942 provide the declaration of the operating system to be installed. To
7943 that end, the installation system comes with three text editors: GNU nano
7944 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7945 nvi (a clone of the original BSD @command{vi} editor).
7946 We strongly recommend storing that file on the target root file system, say,
7947 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7948 configuration file once you have rebooted into the newly-installed system.
7950 @xref{Using the Configuration System}, for an overview of the
7951 configuration file. The example configurations discussed in that
7952 section are available under @file{/etc/configuration} in the
7953 installation image. Thus, to get started with a system configuration
7954 providing a graphical display server (a ``desktop'' system), you can run
7955 something along these lines:
7959 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7960 # zile /mnt/etc/config.scm
7963 You should pay attention to what your configuration file contains, and
7968 Make sure the @code{grub-configuration} form refers to the target you
7969 want to install GRUB on. It should mention @code{grub-bootloader} if
7970 you are installing GRUB in the legacy way, or @code{grub-efi-bootloader}
7971 for newer UEFI systems. For legacy systems, the @code{target} field
7972 names a device, like @code{/dev/sda}; for UEFI systems it names a path
7973 to a mounted EFI partition, like @code{/boot/efi}, and do make sure the
7974 path is actually mounted.
7977 Be sure that your partition labels match the value of their respective
7978 @code{device} fields in your @code{file-system} configuration, assuming
7979 your @code{file-system} configuration sets the value of @code{title} to
7983 If there are encrypted or RAID partitions, make sure to add a
7984 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7987 Once you are done preparing the configuration file, the new system must
7988 be initialized (remember that the target root file system is mounted
7992 guix system init /mnt/etc/config.scm /mnt
7996 This copies all the necessary files and installs GRUB on
7997 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7998 more information, @pxref{Invoking guix system}. This command may trigger
7999 downloads or builds of missing packages, which can take some time.
8001 Once that command has completed---and hopefully succeeded!---you can run
8002 @command{reboot} and boot into the new system. The @code{root} password
8003 in the new system is initially empty; other users' passwords need to be
8004 initialized by running the @command{passwd} command as @code{root},
8005 unless your configuration specifies otherwise
8006 (@pxref{user-account-password, user account passwords}).
8008 @cindex upgrading GuixSD
8009 From then on, you can update GuixSD whenever you want by running
8010 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
8011 then running @command{guix system reconfigure} to build a new system
8012 generation with the latest packages and services (@pxref{Invoking guix
8013 system}). We recommend doing that regularly so that your system
8014 includes the latest security updates (@pxref{Security Updates}).
8016 Join us on @code{#guix} on the Freenode IRC network or on
8017 @file{guix-devel@@gnu.org} to share your experience---good or not so
8020 @node Installing GuixSD in a VM
8021 @subsection Installing GuixSD in a Virtual Machine
8023 @cindex virtual machine, GuixSD installation
8024 @cindex virtual private server (VPS)
8025 @cindex VPS (virtual private server)
8026 If you'd like to install GuixSD in a virtual machine (VM) or on a
8027 virtual private server (VPS) rather than on your beloved machine, this
8030 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
8031 disk image, follow these steps:
8035 First, retrieve and decompress the GuixSD installation image as
8036 described previously (@pxref{USB Stick Installation}).
8039 Create a disk image that will hold the installed system. To make a
8040 qcow2-formatted disk image, use the @command{qemu-img} command:
8043 qemu-img create -f qcow2 guixsd.img 50G
8046 The resulting file will be much smaller than 50 GB (typically less than
8047 1 MB), but it will grow as the virtualized storage device is filled up.
8050 Boot the USB installation image in an VM:
8053 qemu-system-x86_64 -m 1024 -smp 1 \
8054 -net user -net nic,model=virtio -boot menu=on \
8055 -drive file=guixsd-install-@value{VERSION}.@var{system} \
8056 -drive file=guixsd.img
8059 The ordering of the drives matters.
8061 In the VM console, quickly press the @kbd{F12} key to enter the boot
8062 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
8066 You're now root in the VM, proceed with the installation process.
8067 @xref{Preparing for Installation}, and follow the instructions.
8070 Once installation is complete, you can boot the system that's on your
8071 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
8074 @node Building the Installation Image
8075 @subsection Building the Installation Image
8077 @cindex installation image
8078 The installation image described above was built using the @command{guix
8079 system} command, specifically:
8082 guix system disk-image gnu/system/install.scm
8085 Have a look at @file{gnu/system/install.scm} in the source tree,
8086 and see also @ref{Invoking guix system} for more information
8087 about the installation image.
8089 @node System Configuration
8090 @section System Configuration
8092 @cindex system configuration
8093 The Guix System Distribution supports a consistent whole-system configuration
8094 mechanism. By that we mean that all aspects of the global system
8095 configuration---such as the available system services, timezone and
8096 locale settings, user accounts---are declared in a single place. Such
8097 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
8099 One of the advantages of putting all the system configuration under the
8100 control of Guix is that it supports transactional system upgrades, and
8101 makes it possible to roll back to a previous system instantiation,
8102 should something go wrong with the new one (@pxref{Features}). Another
8103 advantage is that it makes it easy to replicate the exact same configuration
8104 across different machines, or at different points in time, without
8105 having to resort to additional administration tools layered on top of
8106 the own tools of the system.
8107 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
8109 This section describes this mechanism. First we focus on the system
8110 administrator's viewpoint---explaining how the system is configured and
8111 instantiated. Then we show how this mechanism can be extended, for
8112 instance to support new system services.
8115 * Using the Configuration System:: Customizing your GNU system.
8116 * operating-system Reference:: Detail of operating-system declarations.
8117 * File Systems:: Configuring file system mounts.
8118 * Mapped Devices:: Block device extra processing.
8119 * User Accounts:: Specifying user accounts.
8120 * Locales:: Language and cultural convention settings.
8121 * Services:: Specifying system services.
8122 * Setuid Programs:: Programs running with root privileges.
8123 * X.509 Certificates:: Authenticating HTTPS servers.
8124 * Name Service Switch:: Configuring libc's name service switch.
8125 * Initial RAM Disk:: Linux-Libre bootstrapping.
8126 * Bootloader Configuration:: Configuring the boot loader.
8127 * Invoking guix system:: Instantiating a system configuration.
8128 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
8129 * Defining Services:: Adding new service definitions.
8132 @node Using the Configuration System
8133 @subsection Using the Configuration System
8135 The operating system is configured by providing an
8136 @code{operating-system} declaration in a file that can then be passed to
8137 the @command{guix system} command (@pxref{Invoking guix system}). A
8138 simple setup, with the default system services, the default Linux-Libre
8139 kernel, initial RAM disk, and boot loader looks like this:
8141 @findex operating-system
8143 @include os-config-bare-bones.texi
8146 This example should be self-describing. Some of the fields defined
8147 above, such as @code{host-name} and @code{bootloader}, are mandatory.
8148 Others, such as @code{packages} and @code{services}, can be omitted, in
8149 which case they get a default value.
8151 Below we discuss the effect of some of the most important fields
8152 (@pxref{operating-system Reference}, for details about all the available
8153 fields), and how to @dfn{instantiate} the operating system using
8154 @command{guix system}.
8156 @unnumberedsubsubsec Globally-Visible Packages
8158 @vindex %base-packages
8159 The @code{packages} field lists packages that will be globally visible
8160 on the system, for all user accounts---i.e., in every user's @code{PATH}
8161 environment variable---in addition to the per-user profiles
8162 (@pxref{Invoking guix package}). The @var{%base-packages} variable
8163 provides all the tools one would expect for basic user and administrator
8164 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
8165 the GNU Zile lightweight text editor, @command{find}, @command{grep},
8166 etc. The example above adds tcpdump to those, taken from the @code{(gnu
8167 packages admin)} module (@pxref{Package Modules}). The
8168 @code{(list package output)} syntax can be used to add a specific output
8172 (use-modules (gnu packages))
8173 (use-modules (gnu packages dns))
8177 (packages (cons (list bind "utils")
8181 @findex specification->package
8182 Referring to packages by variable name, like @var{tcpdump} above, has
8183 the advantage of being unambiguous; it also allows typos and such to be
8184 diagnosed right away as ``unbound variables''. The downside is that one
8185 needs to know which module defines which package, and to augment the
8186 @code{use-package-modules} line accordingly. To avoid that, one can use
8187 the @code{specification->package} procedure of the @code{(gnu packages)}
8188 module, which returns the best package for a given name or name and
8192 (use-modules (gnu packages))
8196 (packages (append (map specification->package
8197 '("tcpdump" "htop" "gnupg@@2.0"))
8201 @unnumberedsubsubsec System Services
8204 @vindex %base-services
8205 The @code{services} field lists @dfn{system services} to be made
8206 available when the system starts (@pxref{Services}).
8207 The @code{operating-system} declaration above specifies that, in
8208 addition to the basic services, we want the @command{lshd} secure shell
8209 daemon listening on port 2222 (@pxref{Networking Services,
8210 @code{lsh-service}}). Under the hood,
8211 @code{lsh-service} arranges so that @code{lshd} is started with the
8212 right command-line options, possibly with supporting configuration files
8213 generated as needed (@pxref{Defining Services}).
8215 @cindex customization, of services
8216 @findex modify-services
8217 Occasionally, instead of using the base services as is, you will want to
8218 customize them. To do this, use @code{modify-services} (@pxref{Service
8219 Reference, @code{modify-services}}) to modify the list.
8221 For example, suppose you want to modify @code{guix-daemon} and Mingetty
8222 (the console log-in) in the @var{%base-services} list (@pxref{Base
8223 Services, @code{%base-services}}). To do that, you can write the
8224 following in your operating system declaration:
8227 (define %my-services
8228 ;; My very own list of services.
8229 (modify-services %base-services
8230 (guix-service-type config =>
8233 (use-substitutes? #f)
8234 (extra-options '("--gc-keep-derivations"))))
8235 (mingetty-service-type config =>
8236 (mingetty-configuration
8237 (inherit config)))))
8241 (services %my-services))
8244 This changes the configuration---i.e., the service parameters---of the
8245 @code{guix-service-type} instance, and that of all the
8246 @code{mingetty-service-type} instances in the @var{%base-services} list.
8247 Observe how this is accomplished: first, we arrange for the original
8248 configuration to be bound to the identifier @code{config} in the
8249 @var{body}, and then we write the @var{body} so that it evaluates to the
8250 desired configuration. In particular, notice how we use @code{inherit}
8251 to create a new configuration which has the same values as the old
8252 configuration, but with a few modifications.
8254 @cindex encrypted disk
8255 The configuration for a typical ``desktop'' usage, with an encrypted
8256 root partition, the X11 display
8257 server, GNOME and Xfce (users can choose which of these desktop
8258 environments to use at the log-in screen by pressing @kbd{F1}), network
8259 management, power management, and more, would look like this:
8262 @include os-config-desktop.texi
8265 A graphical UEFI system with a choice of lightweight window managers
8266 instead of full-blown desktop environments would look like this:
8269 @include os-config-lightweight-desktop.texi
8272 @xref{Desktop Services}, for the exact list of services provided by
8273 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8274 information about the @code{nss-certs} package that is used here.
8276 Again, @var{%desktop-services} is just a list of service objects. If
8277 you want to remove services from there, you can do so using the
8278 procedures for list filtering (@pxref{SRFI-1 Filtering and
8279 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8280 following expression returns a list that contains all the services in
8281 @var{%desktop-services} minus the Avahi service:
8284 (remove (lambda (service)
8285 (eq? (service-kind service) avahi-service-type))
8289 @unnumberedsubsubsec Instantiating the System
8291 Assuming the @code{operating-system} declaration
8292 is stored in the @file{my-system-config.scm}
8293 file, the @command{guix system reconfigure my-system-config.scm} command
8294 instantiates that configuration, and makes it the default GRUB boot
8295 entry (@pxref{Invoking guix system}).
8297 The normal way to change the system configuration is by updating this
8298 file and re-running @command{guix system reconfigure}. One should never
8299 have to touch files in @file{/etc} or to run commands that modify the
8300 system state such as @command{useradd} or @command{grub-install}. In
8301 fact, you must avoid that since that would not only void your warranty
8302 but also prevent you from rolling back to previous versions of your
8303 system, should you ever need to.
8305 @cindex roll-back, of the operating system
8306 Speaking of roll-back, each time you run @command{guix system
8307 reconfigure}, a new @dfn{generation} of the system is created---without
8308 modifying or deleting previous generations. Old system generations get
8309 an entry in the bootloader boot menu, allowing you to boot them in case
8310 something went wrong with the latest generation. Reassuring, no? The
8311 @command{guix system list-generations} command lists the system
8312 generations available on disk. It is also possible to roll back the
8313 system via the commands @command{guix system roll-back} and
8314 @command{guix system switch-generation}.
8316 Although the command @command{guix system reconfigure} will not modify
8317 previous generations, must take care when the current generation is not
8318 the latest (e.g., after invoking @command{guix system roll-back}), since
8319 the operation might overwrite a later generation (@pxref{Invoking guix
8322 @unnumberedsubsubsec The Programming Interface
8324 At the Scheme level, the bulk of an @code{operating-system} declaration
8325 is instantiated with the following monadic procedure (@pxref{The Store
8328 @deffn {Monadic Procedure} operating-system-derivation os
8329 Return a derivation that builds @var{os}, an @code{operating-system}
8330 object (@pxref{Derivations}).
8332 The output of the derivation is a single directory that refers to all
8333 the packages, configuration files, and other supporting files needed to
8334 instantiate @var{os}.
8337 This procedure is provided by the @code{(gnu system)} module. Along
8338 with @code{(gnu services)} (@pxref{Services}), this module contains the
8339 guts of GuixSD. Make sure to visit it!
8342 @node operating-system Reference
8343 @subsection @code{operating-system} Reference
8345 This section summarizes all the options available in
8346 @code{operating-system} declarations (@pxref{Using the Configuration
8349 @deftp {Data Type} operating-system
8350 This is the data type representing an operating system configuration.
8351 By that, we mean all the global system configuration, not per-user
8352 configuration (@pxref{Using the Configuration System}).
8355 @item @code{kernel} (default: @var{linux-libre})
8356 The package object of the operating system kernel to use@footnote{Currently
8357 only the Linux-libre kernel is supported. In the future, it will be
8358 possible to use the GNU@tie{}Hurd.}.
8360 @item @code{kernel-arguments} (default: @code{'()})
8361 List of strings or gexps representing additional arguments to pass on
8362 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8364 @item @code{bootloader}
8365 The system bootloader configuration object. @xref{Bootloader Configuration}.
8367 @item @code{initrd} (default: @code{base-initrd})
8369 @cindex initial RAM disk
8370 A two-argument monadic procedure that returns an initial RAM disk for
8371 the Linux kernel. @xref{Initial RAM Disk}.
8373 @item @code{firmware} (default: @var{%base-firmware})
8375 List of firmware packages loadable by the operating system kernel.
8377 The default includes firmware needed for Atheros- and Broadcom-based
8378 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8379 respectively). @xref{Hardware Considerations}, for more info on
8382 @item @code{host-name}
8385 @item @code{hosts-file}
8387 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8388 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8389 Reference Manual}). The default is a file with entries for
8390 @code{localhost} and @var{host-name}.
8392 @item @code{mapped-devices} (default: @code{'()})
8393 A list of mapped devices. @xref{Mapped Devices}.
8395 @item @code{file-systems}
8396 A list of file systems. @xref{File Systems}.
8398 @item @code{swap-devices} (default: @code{'()})
8399 @cindex swap devices
8400 A list of strings identifying devices or files to be used for ``swap
8401 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8402 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8403 It is possible to specify a swap file in a file system on a mapped
8404 device, provided that the necessary device mapping and file system are
8405 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8407 @item @code{users} (default: @code{%base-user-accounts})
8408 @itemx @code{groups} (default: @var{%base-groups})
8409 List of user accounts and groups. @xref{User Accounts}.
8411 @item @code{skeletons} (default: @code{(default-skeletons)})
8412 A list target file name/file-like object tuples (@pxref{G-Expressions,
8413 file-like objects}). These are the skeleton files that will be added to
8414 the home directory of newly-created user accounts.
8416 For instance, a valid value may look like this:
8419 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8420 (".guile" ,(plain-file "guile"
8421 "(use-modules (ice-9 readline))
8422 (activate-readline)")))
8425 @item @code{issue} (default: @var{%default-issue})
8426 A string denoting the contents of the @file{/etc/issue} file, which is
8427 displayed when users log in on a text console.
8429 @item @code{packages} (default: @var{%base-packages})
8430 The set of packages installed in the global profile, which is accessible
8431 at @file{/run/current-system/profile}.
8433 The default set includes core utilities and it is good practice to
8434 install non-core utilities in user profiles (@pxref{Invoking guix
8437 @item @code{timezone}
8438 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8440 You can run the @command{tzselect} command to find out which timezone
8441 string corresponds to your region. Choosing an invalid timezone name
8442 causes @command{guix system} to fail.
8444 @item @code{locale} (default: @code{"en_US.utf8"})
8445 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8446 Library Reference Manual}). @xref{Locales}, for more information.
8448 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8449 The list of locale definitions to be compiled and that may be used at
8450 run time. @xref{Locales}.
8452 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8453 The list of GNU@tie{}libc packages whose locale data and tools are used
8454 to build the locale definitions. @xref{Locales}, for compatibility
8455 considerations that justify this option.
8457 @item @code{name-service-switch} (default: @var{%default-nss})
8458 Configuration of the libc name service switch (NSS)---a
8459 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8462 @item @code{services} (default: @var{%base-services})
8463 A list of service objects denoting system services. @xref{Services}.
8465 @item @code{pam-services} (default: @code{(base-pam-services)})
8467 @cindex pluggable authentication modules
8468 Linux @dfn{pluggable authentication module} (PAM) services.
8469 @c FIXME: Add xref to PAM services section.
8471 @item @code{setuid-programs} (default: @var{%setuid-programs})
8472 List of string-valued G-expressions denoting setuid programs.
8473 @xref{Setuid Programs}.
8475 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8476 @cindex sudoers file
8477 The contents of the @file{/etc/sudoers} file as a file-like object
8478 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8480 This file specifies which users can use the @command{sudo} command, what
8481 they are allowed to do, and what privileges they may gain. The default
8482 is that only @code{root} and members of the @code{wheel} group may use
8489 @subsection File Systems
8491 The list of file systems to be mounted is specified in the
8492 @code{file-systems} field of the operating system declaration
8493 (@pxref{Using the Configuration System}). Each file system is declared
8494 using the @code{file-system} form, like this:
8498 (mount-point "/home")
8499 (device "/dev/sda3")
8503 As usual, some of the fields are mandatory---those shown in the example
8504 above---while others can be omitted. These are described below.
8506 @deftp {Data Type} file-system
8507 Objects of this type represent file systems to be mounted. They
8508 contain the following members:
8512 This is a string specifying the type of the file system---e.g.,
8515 @item @code{mount-point}
8516 This designates the place where the file system is to be mounted.
8519 This names the ``source'' of the file system. By default it is the name
8520 of a node under @file{/dev}, but its meaning depends on the @code{title}
8521 field described below.
8523 @item @code{title} (default: @code{'device})
8524 This is a symbol that specifies how the @code{device} field is to be
8527 When it is the symbol @code{device}, then the @code{device} field is
8528 interpreted as a file name; when it is @code{label}, then @code{device}
8529 is interpreted as a partition label name; when it is @code{uuid},
8530 @code{device} is interpreted as a partition unique identifier (UUID).
8532 UUIDs may be converted from their string representation (as shown by the
8533 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8534 @code{uuid} form expects 16-byte UUIDs as defined in
8535 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8536 form of UUID used by the ext2 family of file systems and others, but it
8537 is different from ``UUIDs'' found in FAT file systems, for instance.},
8542 (mount-point "/home")
8545 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8548 The @code{label} and @code{uuid} options offer a way to refer to disk
8549 partitions without having to hard-code their actual device
8550 name@footnote{Note that, while it is tempting to use
8551 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8552 result, this is not recommended: These special device nodes are created
8553 by the udev daemon and may be unavailable at the time the device is
8556 However, when the source of a file system is a mapped device (@pxref{Mapped
8557 Devices}), its @code{device} field @emph{must} refer to the mapped
8558 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8559 @code{title} must be set to @code{'device}. This is required so that
8560 the system knows that mounting the file system depends on having the
8561 corresponding device mapping established.
8563 @item @code{flags} (default: @code{'()})
8564 This is a list of symbols denoting mount flags. Recognized flags
8565 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8566 access to special files), @code{no-suid} (ignore setuid and setgid
8567 bits), and @code{no-exec} (disallow program execution.)
8569 @item @code{options} (default: @code{#f})
8570 This is either @code{#f}, or a string denoting mount options.
8572 @item @code{mount?} (default: @code{#t})
8573 This value indicates whether to automatically mount the file system when
8574 the system is brought up. When set to @code{#f}, the file system gets
8575 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8576 is not automatically mounted.
8578 @item @code{needed-for-boot?} (default: @code{#f})
8579 This Boolean value indicates whether the file system is needed when
8580 booting. If that is true, then the file system is mounted when the
8581 initial RAM disk (initrd) is loaded. This is always the case, for
8582 instance, for the root file system.
8584 @item @code{check?} (default: @code{#t})
8585 This Boolean indicates whether the file system needs to be checked for
8586 errors before being mounted.
8588 @item @code{create-mount-point?} (default: @code{#f})
8589 When true, the mount point is created if it does not exist yet.
8591 @item @code{dependencies} (default: @code{'()})
8592 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8593 representing file systems that must be mounted or mapped devices that
8594 must be opened before (and unmounted or closed after) this one.
8596 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8597 a dependency of @file{/sys/fs/cgroup/cpu} and
8598 @file{/sys/fs/cgroup/memory}.
8600 Another example is a file system that depends on a mapped device, for
8601 example for an encrypted partition (@pxref{Mapped Devices}).
8605 The @code{(gnu system file-systems)} exports the following useful
8608 @defvr {Scheme Variable} %base-file-systems
8609 These are essential file systems that are required on normal systems,
8610 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8611 below.) Operating system declarations should always contain at least
8615 @defvr {Scheme Variable} %pseudo-terminal-file-system
8616 This is the file system to be mounted as @file{/dev/pts}. It supports
8617 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8618 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8619 Manual}). Pseudo-terminals are used by terminal emulators such as
8623 @defvr {Scheme Variable} %shared-memory-file-system
8624 This file system is mounted as @file{/dev/shm} and is used to support
8625 memory sharing across processes (@pxref{Memory-mapped I/O,
8626 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8629 @defvr {Scheme Variable} %immutable-store
8630 This file system performs a read-only ``bind mount'' of
8631 @file{/gnu/store}, making it read-only for all the users including
8632 @code{root}. This prevents against accidental modification by software
8633 running as @code{root} or by system administrators.
8635 The daemon itself is still able to write to the store: it remounts it
8636 read-write in its own ``name space.''
8639 @defvr {Scheme Variable} %binary-format-file-system
8640 The @code{binfmt_misc} file system, which allows handling of arbitrary
8641 executable file types to be delegated to user space. This requires the
8642 @code{binfmt.ko} kernel module to be loaded.
8645 @defvr {Scheme Variable} %fuse-control-file-system
8646 The @code{fusectl} file system, which allows unprivileged users to mount
8647 and unmount user-space FUSE file systems. This requires the
8648 @code{fuse.ko} kernel module to be loaded.
8651 @node Mapped Devices
8652 @subsection Mapped Devices
8654 @cindex device mapping
8655 @cindex mapped devices
8656 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8657 such as a hard disk partition, can be @dfn{mapped} into another device,
8658 usually in @code{/dev/mapper/},
8659 with additional processing over the data that flows through
8660 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8661 concept of a ``mapped device'' and that of a file system: both boil down
8662 to @emph{translating} input/output operations made on a file to
8663 operations on its backing store. Thus, the Hurd implements mapped
8664 devices, like file systems, using the generic @dfn{translator} mechanism
8665 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8666 typical example is encryption device mapping: all writes to the mapped
8667 device are encrypted, and all reads are deciphered, transparently.
8668 Guix extends this notion by considering any device or set of devices that
8669 are @dfn{transformed} in some way to create a new device; for instance,
8670 RAID devices are obtained by @dfn{assembling} several other devices, such
8671 as hard disks or partitions, into a new one that behaves as one partition.
8672 Other examples, not yet implemented, are LVM logical volumes.
8674 Mapped devices are declared using the @code{mapped-device} form,
8675 defined as follows; for examples, see below.
8677 @deftp {Data Type} mapped-device
8678 Objects of this type represent device mappings that will be made when
8679 the system boots up.
8683 This is either a string specifying the name of the block device to be mapped,
8684 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8685 need to be assembled for creating a new one.
8688 This string specifies the name of the resulting mapped device. For
8689 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8690 specifying @code{"my-partition"} leads to the creation of
8691 the @code{"/dev/mapper/my-partition"} device.
8692 For RAID devices of type @code{raid-device-mapping}, the full device name
8693 such as @code{"/dev/md0"} needs to be given.
8696 This must be a @code{mapped-device-kind} object, which specifies how
8697 @var{source} is mapped to @var{target}.
8701 @defvr {Scheme Variable} luks-device-mapping
8702 This defines LUKS block device encryption using the @command{cryptsetup}
8703 command from the package with the same name. It relies on the
8704 @code{dm-crypt} Linux kernel module.
8707 @defvr {Scheme Variable} raid-device-mapping
8708 This defines a RAID device, which is assembled using the @code{mdadm}
8709 command from the package with the same name. It requires a Linux kernel
8710 module for the appropriate RAID level to be loaded, such as @code{raid456}
8711 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8714 @cindex disk encryption
8716 The following example specifies a mapping from @file{/dev/sda3} to
8717 @file{/dev/mapper/home} using LUKS---the
8718 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8719 standard mechanism for disk encryption.
8720 The @file{/dev/mapper/home}
8721 device can then be used as the @code{device} of a @code{file-system}
8722 declaration (@pxref{File Systems}).
8726 (source "/dev/sda3")
8728 (type luks-device-mapping))
8731 Alternatively, to become independent of device numbering, one may obtain
8732 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8736 cryptsetup luksUUID /dev/sda3
8739 and use it as follows:
8743 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8745 (type luks-device-mapping))
8748 @cindex swap encryption
8749 It is also desirable to encrypt swap space, since swap space may contain
8750 sensitive data. One way to accomplish that is to use a swap file in a
8751 file system on a device mapped via LUKS encryption. In this way, the
8752 swap file is encrypted because the entire device is encrypted.
8753 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8755 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8756 may be declared as follows:
8760 (source (list "/dev/sda1" "/dev/sdb1"))
8762 (type raid-device-mapping))
8765 The @file{/dev/md0} device can then be used as the @code{device} of a
8766 @code{file-system} declaration (@pxref{File Systems}).
8767 Note that the RAID level need not be given; it is chosen during the
8768 initial creation and formatting of the RAID device and is determined
8769 automatically later.
8773 @subsection User Accounts
8777 @cindex user accounts
8778 User accounts and groups are entirely managed through the
8779 @code{operating-system} declaration. They are specified with the
8780 @code{user-account} and @code{user-group} forms:
8786 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8788 "video" ;video devices such as webcams
8789 "cdrom")) ;the good ol' CD-ROM
8790 (comment "Bob's sister")
8791 (home-directory "/home/alice"))
8794 When booting or upon completion of @command{guix system reconfigure},
8795 the system ensures that only the user accounts and groups specified in
8796 the @code{operating-system} declaration exist, and with the specified
8797 properties. Thus, account or group creations or modifications made by
8798 directly invoking commands such as @command{useradd} are lost upon
8799 reconfiguration or reboot. This ensures that the system remains exactly
8802 @deftp {Data Type} user-account
8803 Objects of this type represent user accounts. The following members may
8808 The name of the user account.
8812 This is the name (a string) or identifier (a number) of the user group
8813 this account belongs to.
8815 @item @code{supplementary-groups} (default: @code{'()})
8816 Optionally, this can be defined as a list of group names that this
8819 @item @code{uid} (default: @code{#f})
8820 This is the user ID for this account (a number), or @code{#f}. In the
8821 latter case, a number is automatically chosen by the system when the
8824 @item @code{comment} (default: @code{""})
8825 A comment about the account, such as the account owner's full name.
8827 @item @code{home-directory}
8828 This is the name of the home directory for the account.
8830 @item @code{create-home-directory?} (default: @code{#t})
8831 Indicates whether the home directory of this account should be created
8832 if it does not exist yet.
8834 @item @code{shell} (default: Bash)
8835 This is a G-expression denoting the file name of a program to be used as
8836 the shell (@pxref{G-Expressions}).
8838 @item @code{system?} (default: @code{#f})
8839 This Boolean value indicates whether the account is a ``system''
8840 account. System accounts are sometimes treated specially; for instance,
8841 graphical login managers do not list them.
8843 @anchor{user-account-password}
8844 @item @code{password} (default: @code{#f})
8845 You would normally leave this field to @code{#f}, initialize user
8846 passwords as @code{root} with the @command{passwd} command, and then let
8847 users change it with @command{passwd}. Passwords set with
8848 @command{passwd} are of course preserved across reboot and
8851 If you @emph{do} want to have a preset password for an account, then
8852 this field must contain the encrypted password, as a string.
8853 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8854 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8855 Manual}, for information on Guile's @code{crypt} procedure.
8861 User group declarations are even simpler:
8864 (user-group (name "students"))
8867 @deftp {Data Type} user-group
8868 This type is for, well, user groups. There are just a few fields:
8872 The name of the group.
8874 @item @code{id} (default: @code{#f})
8875 The group identifier (a number). If @code{#f}, a new number is
8876 automatically allocated when the group is created.
8878 @item @code{system?} (default: @code{#f})
8879 This Boolean value indicates whether the group is a ``system'' group.
8880 System groups have low numerical IDs.
8882 @item @code{password} (default: @code{#f})
8883 What, user groups can have a password? Well, apparently yes. Unless
8884 @code{#f}, this field specifies the password of the group.
8889 For convenience, a variable lists all the basic user groups one may
8892 @defvr {Scheme Variable} %base-groups
8893 This is the list of basic user groups that users and/or packages expect
8894 to be present on the system. This includes groups such as ``root'',
8895 ``wheel'', and ``users'', as well as groups used to control access to
8896 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8899 @defvr {Scheme Variable} %base-user-accounts
8900 This is the list of basic system accounts that programs may expect to
8901 find on a GNU/Linux system, such as the ``nobody'' account.
8903 Note that the ``root'' account is not included here. It is a
8904 special-case and is automatically added whether or not it is specified.
8911 A @dfn{locale} defines cultural conventions for a particular language
8912 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8913 Reference Manual}). Each locale has a name that typically has the form
8914 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8915 @code{fr_LU.utf8} designates the locale for the French language, with
8916 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8918 @cindex locale definition
8919 Usually, you will want to specify the default locale for the machine
8920 using the @code{locale} field of the @code{operating-system} declaration
8921 (@pxref{operating-system Reference, @code{locale}}).
8923 The selected locale is automatically added to the @dfn{locale
8924 definitions} known to the system if needed, with its codeset inferred
8925 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8926 @code{UTF-8} codeset. Additional locale definitions can be specified in
8927 the @code{locale-definitions} slot of @code{operating-system}---this is
8928 useful, for instance, if the codeset could not be inferred from the
8929 locale name. The default set of locale definitions includes some widely
8930 used locales, but not all the available locales, in order to save space.
8932 For instance, to add the North Frisian locale for Germany, the value of
8936 (cons (locale-definition
8937 (name "fy_DE.utf8") (source "fy_DE"))
8938 %default-locale-definitions)
8941 Likewise, to save space, one might want @code{locale-definitions} to
8942 list only the locales that are actually used, as in:
8945 (list (locale-definition
8946 (name "ja_JP.eucjp") (source "ja_JP")
8947 (charset "EUC-JP")))
8951 The compiled locale definitions are available at
8952 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8953 version, which is the default location where the GNU@tie{}libc provided
8954 by Guix looks for locale data. This can be overridden using the
8955 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8956 @code{LOCPATH} and locale packages}).
8958 The @code{locale-definition} form is provided by the @code{(gnu system
8959 locale)} module. Details are given below.
8961 @deftp {Data Type} locale-definition
8962 This is the data type of a locale definition.
8967 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8968 Reference Manual}, for more information on locale names.
8971 The name of the source for that locale. This is typically the
8972 @code{@var{language}_@var{territory}} part of the locale name.
8974 @item @code{charset} (default: @code{"UTF-8"})
8975 The ``character set'' or ``code set'' for that locale,
8976 @uref{http://www.iana.org/assignments/character-sets, as defined by
8982 @defvr {Scheme Variable} %default-locale-definitions
8983 A list of commonly used UTF-8 locales, used as the default
8984 value of the @code{locale-definitions} field of @code{operating-system}
8988 @cindex normalized codeset in locale names
8989 These locale definitions use the @dfn{normalized codeset} for the part
8990 that follows the dot in the name (@pxref{Using gettextized software,
8991 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8992 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8996 @subsubsection Locale Data Compatibility Considerations
8998 @cindex incompatibility, of locale data
8999 @code{operating-system} declarations provide a @code{locale-libcs} field
9000 to specify the GNU@tie{}libc packages that are used to compile locale
9001 declarations (@pxref{operating-system Reference}). ``Why would I
9002 care?'', you may ask. Well, it turns out that the binary format of
9003 locale data is occasionally incompatible from one libc version to
9006 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
9007 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
9008 For instance, a program linked against libc version 2.21 is unable to
9009 read locale data produced with libc 2.22; worse, that program
9010 @emph{aborts} instead of simply ignoring the incompatible locale
9011 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
9012 the incompatible locale data, which is already an improvement.}.
9013 Similarly, a program linked against libc 2.22 can read most, but not
9014 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
9015 data is incompatible); thus calls to @code{setlocale} may fail, but
9016 programs will not abort.
9018 The ``problem'' in GuixSD is that users have a lot of freedom: They can
9019 choose whether and when to upgrade software in their profiles, and might
9020 be using a libc version different from the one the system administrator
9021 used to build the system-wide locale data.
9023 Fortunately, unprivileged users can also install their own locale data
9024 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
9025 @code{GUIX_LOCPATH} and locale packages}).
9027 Still, it is best if the system-wide locale data at
9028 @file{/run/current-system/locale} is built for all the libc versions
9029 actually in use on the system, so that all the programs can access
9030 it---this is especially crucial on a multi-user system. To do that, the
9031 administrator can specify several libc packages in the
9032 @code{locale-libcs} field of @code{operating-system}:
9035 (use-package-modules base)
9039 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
9042 This example would lead to a system containing locale definitions for
9043 both libc 2.21 and the current version of libc in
9044 @file{/run/current-system/locale}.
9048 @subsection Services
9050 @cindex system services
9051 An important part of preparing an @code{operating-system} declaration is
9052 listing @dfn{system services} and their configuration (@pxref{Using the
9053 Configuration System}). System services are typically daemons launched
9054 when the system boots, or other actions needed at that time---e.g.,
9055 configuring network access.
9057 GuixSD has a broad definition of ``service'' (@pxref{Service
9058 Composition}), but many services are managed by the GNU@tie{}Shepherd
9059 (@pxref{Shepherd Services}). On a running system, the @command{herd}
9060 command allows you to list the available services, show their status,
9061 start and stop them, or do other specific operations (@pxref{Jump
9062 Start,,, shepherd, The GNU Shepherd Manual}). For example:
9068 The above command, run as @code{root}, lists the currently defined
9069 services. The @command{herd doc} command shows a synopsis of the given
9074 Run libc's name service cache daemon (nscd).
9077 The @command{start}, @command{stop}, and @command{restart} sub-commands
9078 have the effect you would expect. For instance, the commands below stop
9079 the nscd service and restart the Xorg display server:
9083 Service nscd has been stopped.
9084 # herd restart xorg-server
9085 Service xorg-server has been stopped.
9086 Service xorg-server has been started.
9089 The following sections document the available services, starting with
9090 the core services, that may be used in an @code{operating-system}
9094 * Base Services:: Essential system services.
9095 * Scheduled Job Execution:: The mcron service.
9096 * Log Rotation:: The rottlog service.
9097 * Networking Services:: Network setup, SSH daemon, etc.
9098 * X Window:: Graphical display.
9099 * Printing Services:: Local and remote printer support.
9100 * Desktop Services:: D-Bus and desktop services.
9101 * Database Services:: SQL databases, key-value stores, etc.
9102 * Mail Services:: IMAP, POP3, SMTP, and all that.
9103 * Messaging Services:: Messaging services.
9104 * Monitoring Services:: Monitoring services.
9105 * Kerberos Services:: Kerberos services.
9106 * Web Services:: Web servers.
9107 * DNS Services:: DNS daemons.
9108 * VPN Services:: VPN daemons.
9109 * Network File System:: NFS related services.
9110 * Continuous Integration:: The Cuirass service.
9111 * Power management Services:: The TLP tool.
9112 * Audio Services:: The MPD.
9113 * Virtualization Services:: Virtualization services.
9114 * Miscellaneous Services:: Other services.
9118 @subsubsection Base Services
9120 The @code{(gnu services base)} module provides definitions for the basic
9121 services that one expects from the system. The services exported by
9122 this module are listed below.
9124 @defvr {Scheme Variable} %base-services
9125 This variable contains a list of basic services (@pxref{Service Types
9126 and Services}, for more information on service objects) one would
9127 expect from the system: a login service (mingetty) on each tty, syslogd,
9128 the libc name service cache daemon (nscd), the udev device manager, and
9131 This is the default value of the @code{services} field of
9132 @code{operating-system} declarations. Usually, when customizing a
9133 system, you will want to append services to @var{%base-services}, like
9137 (cons* (avahi-service) (lsh-service) %base-services)
9141 @defvr {Scheme Variable} special-files-service-type
9142 This is the service that sets up ``special files'' such as
9143 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
9145 The value associated with @code{special-files-service-type} services
9146 must be a list of tuples where the first element is the ``special file''
9147 and the second element is its target. By default it is:
9149 @cindex @file{/bin/sh}
9150 @cindex @file{sh}, in @file{/bin}
9152 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
9155 @cindex @file{/usr/bin/env}
9156 @cindex @file{env}, in @file{/usr/bin}
9157 If you want to add, say, @code{/usr/bin/env} to your system, you can
9161 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
9162 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
9165 Since this is part of @code{%base-services}, you can use
9166 @code{modify-services} to customize the set of special files
9167 (@pxref{Service Reference, @code{modify-services}}). But the simple way
9168 to add a special file is @i{via} the @code{extra-special-file} procedure
9172 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
9173 Use @var{target} as the ``special file'' @var{file}.
9175 For example, adding the following lines to the @code{services} field of
9176 your operating system declaration leads to a @file{/usr/bin/env}
9180 (extra-special-file "/usr/bin/env"
9181 (file-append coreutils "/bin/env"))
9185 @deffn {Scheme Procedure} host-name-service @var{name}
9186 Return a service that sets the host name to @var{name}.
9189 @deffn {Scheme Procedure} login-service @var{config}
9190 Return a service to run login according to @var{config}, a
9191 @code{<login-configuration>} object, which specifies the message of the day,
9195 @deftp {Data Type} login-configuration
9196 This is the data type representing the configuration of login.
9201 @cindex message of the day
9202 A file-like object containing the ``message of the day''.
9204 @item @code{allow-empty-passwords?} (default: @code{#t})
9205 Allow empty passwords by default so that first-time users can log in when
9206 the 'root' account has just been created.
9211 @deffn {Scheme Procedure} mingetty-service @var{config}
9212 Return a service to run mingetty according to @var{config}, a
9213 @code{<mingetty-configuration>} object, which specifies the tty to run, among
9217 @deftp {Data Type} mingetty-configuration
9218 This is the data type representing the configuration of Mingetty, which
9219 provides the default implementation of virtual console log-in.
9224 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
9226 @item @code{auto-login} (default: @code{#f})
9227 When true, this field must be a string denoting the user name under
9228 which the system automatically logs in. When it is @code{#f}, a
9229 user name and password must be entered to log in.
9231 @item @code{login-program} (default: @code{#f})
9232 This must be either @code{#f}, in which case the default log-in program
9233 is used (@command{login} from the Shadow tool suite), or a gexp denoting
9234 the name of the log-in program.
9236 @item @code{login-pause?} (default: @code{#f})
9237 When set to @code{#t} in conjunction with @var{auto-login}, the user
9238 will have to press a key before the log-in shell is launched.
9240 @item @code{mingetty} (default: @var{mingetty})
9241 The Mingetty package to use.
9246 @deffn {Scheme Procedure} agetty-service @var{config}
9247 Return a service to run agetty according to @var{config}, an
9248 @code{<agetty-configuration>} object, which specifies the tty to run,
9252 @deftp {Data Type} agetty-configuration
9253 This is the data type representing the configuration of agetty, which
9254 implements virtual and serial console log-in. See the @code{agetty(8)}
9255 man page for more information.
9260 The name of the console this agetty runs on, as a string---e.g.,
9261 @code{"ttyS0"}. This argument is mandatory.
9263 @item @code{baud-rate} (default: @code{#f})
9264 A string containing a comma-separated list of one or more baud rates, in
9267 @item @code{term} (default: @code{#f})
9268 A string containing the value used for the @code{TERM} environment
9271 @item @code{eight-bits?} (default: @code{#f})
9272 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9275 @item @code{auto-login} (default: @code{#f})
9276 When passed a login name, as a string, the specified user will be logged
9277 in automatically without prompting for their login name or password.
9279 @item @code{no-reset?} (default: @code{#f})
9280 When @code{#t}, don't reset terminal cflags (control modes).
9282 @item @code{host} (default: @code{#f})
9283 This accepts a string containing the "login_host", which will be written
9284 into the @file{/var/run/utmpx} file.
9286 @item @code{remote?} (default: @code{#f})
9287 When set to @code{#t} in conjunction with @var{host}, this will add an
9288 @code{-r} fakehost option to the command line of the login program
9289 specified in @var{login-program}.
9291 @item @code{flow-control?} (default: @code{#f})
9292 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9294 @item @code{no-issue?} (default: @code{#f})
9295 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9296 not be displayed before presenting the login prompt.
9298 @item @code{init-string} (default: @code{#f})
9299 This accepts a string that will be sent to the tty or modem before
9300 sending anything else. It can be used to initialize a modem.
9302 @item @code{no-clear?} (default: @code{#f})
9303 When set to @code{#t}, agetty will not clear the screen before showing
9306 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9307 This must be either a gexp denoting the name of a log-in program, or
9308 unset, in which case the default value is the @command{login} from the
9311 @item @code{local-line} (default: @code{#f})
9312 Control the CLOCAL line flag. This accepts one of three symbols as
9313 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9314 the default value chosen by agetty is @code{'auto}.
9316 @item @code{extract-baud?} (default: @code{#f})
9317 When set to @code{#t}, instruct agetty to try to extract the baud rate
9318 from the status messages produced by certain types of modems.
9320 @item @code{skip-login?} (default: @code{#f})
9321 When set to @code{#t}, do not prompt the user for a login name. This
9322 can be used with @var{login-program} field to use non-standard login
9325 @item @code{no-newline?} (default: @code{#f})
9326 When set to @code{#t}, do not print a newline before printing the
9327 @file{/etc/issue} file.
9329 @c Is this dangerous only when used with login-program, or always?
9330 @item @code{login-options} (default: @code{#f})
9331 This option accepts a string containing options that are passed to the
9332 login program. When used with the @var{login-program}, be aware that a
9333 malicious user could try to enter a login name containing embedded
9334 options that could be parsed by the login program.
9336 @item @code{login-pause} (default: @code{#f})
9337 When set to @code{#t}, wait for any key before showing the login prompt.
9338 This can be used in conjunction with @var{auto-login} to save memory by
9339 lazily spawning shells.
9341 @item @code{chroot} (default: @code{#f})
9342 Change root to the specified directory. This option accepts a directory
9345 @item @code{hangup?} (default: @code{#f})
9346 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9349 @item @code{keep-baud?} (default: @code{#f})
9350 When set to @code{#t}, try to keep the existing baud rate. The baud
9351 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9354 @item @code{timeout} (default: @code{#f})
9355 When set to an integer value, terminate if no user name could be read
9356 within @var{timeout} seconds.
9358 @item @code{detect-case?} (default: @code{#f})
9359 When set to @code{#t}, turn on support for detecting an uppercase-only
9360 terminal. This setting will detect a login name containing only
9361 uppercase letters as indicating an uppercase-only terminal and turn on
9362 some upper-to-lower case conversions. Note that this will not support
9365 @item @code{wait-cr?} (default: @code{#f})
9366 When set to @code{#t}, wait for the user or modem to send a
9367 carriage-return or linefeed character before displaying
9368 @file{/etc/issue} or login prompt. This is typically used with the
9369 @var{init-string} option.
9371 @item @code{no-hints?} (default: @code{#f})
9372 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9375 @item @code{no-hostname?} (default: @code{#f})
9376 By default, the hostname is printed. When this option is set to
9377 @code{#t}, no hostname will be shown at all.
9379 @item @code{long-hostname?} (default: @code{#f})
9380 By default, the hostname is only printed until the first dot. When this
9381 option is set to @code{#t}, the fully qualified hostname by
9382 @code{gethostname} or @code{getaddrinfo} is shown.
9384 @item @code{erase-characters} (default: @code{#f})
9385 This option accepts a string of additional characters that should be
9386 interpreted as backspace when the user types their login name.
9388 @item @code{kill-characters} (default: @code{#f})
9389 This option accepts a string that should be interpreted to mean "ignore
9390 all previous characters" (also called a "kill" character) when the types
9393 @item @code{chdir} (default: @code{#f})
9394 This option accepts, as a string, a directory path that will be changed
9397 @item @code{delay} (default: @code{#f})
9398 This options accepts, as an integer, the number of seconds to sleep
9399 before opening the tty and displaying the login prompt.
9401 @item @code{nice} (default: @code{#f})
9402 This option accepts, as an integer, the nice value with which to run the
9403 @command{login} program.
9405 @item @code{extra-options} (default: @code{'()})
9406 This option provides an "escape hatch" for the user to provide arbitrary
9407 command-line arguments to @command{agetty} as a list of strings.
9412 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9413 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9414 according to @var{config}, a @code{<kmscon-configuration>} object, which
9415 specifies the tty to run, among other things.
9418 @deftp {Data Type} kmscon-configuration
9419 This is the data type representing the configuration of Kmscon, which
9420 implements virtual console log-in.
9424 @item @code{virtual-terminal}
9425 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9427 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9428 A gexp denoting the name of the log-in program. The default log-in program is
9429 @command{login} from the Shadow tool suite.
9431 @item @code{login-arguments} (default: @code{'("-p")})
9432 A list of arguments to pass to @command{login}.
9434 @item @code{hardware-acceleration?} (default: #f)
9435 Whether to use hardware acceleration.
9437 @item @code{kmscon} (default: @var{kmscon})
9438 The Kmscon package to use.
9443 @cindex name service cache daemon
9445 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9446 [#:name-services '()]
9447 Return a service that runs the libc name service cache daemon (nscd) with the
9448 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9449 Service Switch}, for an example.
9452 @defvr {Scheme Variable} %nscd-default-configuration
9453 This is the default @code{<nscd-configuration>} value (see below) used
9454 by @code{nscd-service}. It uses the caches defined by
9455 @var{%nscd-default-caches}; see below.
9458 @deftp {Data Type} nscd-configuration
9459 This is the data type representing the name service cache daemon (nscd)
9464 @item @code{name-services} (default: @code{'()})
9465 List of packages denoting @dfn{name services} that must be visible to
9466 the nscd---e.g., @code{(list @var{nss-mdns})}.
9468 @item @code{glibc} (default: @var{glibc})
9469 Package object denoting the GNU C Library providing the @command{nscd}
9472 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9473 Name of the nscd log file. This is where debugging output goes when
9474 @code{debug-level} is strictly positive.
9476 @item @code{debug-level} (default: @code{0})
9477 Integer denoting the debugging levels. Higher numbers mean that more
9478 debugging output is logged.
9480 @item @code{caches} (default: @var{%nscd-default-caches})
9481 List of @code{<nscd-cache>} objects denoting things to be cached; see
9487 @deftp {Data Type} nscd-cache
9488 Data type representing a cache database of nscd and its parameters.
9492 @item @code{database}
9493 This is a symbol representing the name of the database to be cached.
9494 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9495 @code{services}, which designate the corresponding NSS database
9496 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9498 @item @code{positive-time-to-live}
9499 @itemx @code{negative-time-to-live} (default: @code{20})
9500 A number representing the number of seconds during which a positive or
9501 negative lookup result remains in cache.
9503 @item @code{check-files?} (default: @code{#t})
9504 Whether to check for updates of the files corresponding to
9507 For instance, when @var{database} is @code{hosts}, setting this flag
9508 instructs nscd to check for updates in @file{/etc/hosts} and to take
9511 @item @code{persistent?} (default: @code{#t})
9512 Whether the cache should be stored persistently on disk.
9514 @item @code{shared?} (default: @code{#t})
9515 Whether the cache should be shared among users.
9517 @item @code{max-database-size} (default: 32@tie{}MiB)
9518 Maximum size in bytes of the database cache.
9520 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9521 @c settings, so leave them out.
9526 @defvr {Scheme Variable} %nscd-default-caches
9527 List of @code{<nscd-cache>} objects used by default by
9528 @code{nscd-configuration} (see above).
9530 It enables persistent and aggressive caching of service and host name
9531 lookups. The latter provides better host name lookup performance,
9532 resilience in the face of unreliable name servers, and also better
9533 privacy---often the result of host name lookups is in local cache, so
9534 external name servers do not even need to be queried.
9537 @anchor{syslog-configuration-type}
9540 @deftp {Data Type} syslog-configuration
9541 This data type represents the configuration of the syslog daemon.
9544 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9545 The syslog daemon to use.
9547 @item @code{config-file} (default: @code{%default-syslog.conf})
9548 The syslog configuration file to use.
9553 @anchor{syslog-service}
9555 @deffn {Scheme Procedure} syslog-service @var{config}
9556 Return a service that runs a syslog daemon according to @var{config}.
9558 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9559 information on the configuration file syntax.
9562 @anchor{guix-configuration-type}
9563 @deftp {Data Type} guix-configuration
9564 This data type represents the configuration of the Guix build daemon.
9565 @xref{Invoking guix-daemon}, for more information.
9568 @item @code{guix} (default: @var{guix})
9569 The Guix package to use.
9571 @item @code{build-group} (default: @code{"guixbuild"})
9572 Name of the group for build user accounts.
9574 @item @code{build-accounts} (default: @code{10})
9575 Number of build user accounts to create.
9577 @item @code{authorize-key?} (default: @code{#t})
9578 @cindex substitutes, authorization thereof
9579 Whether to authorize the substitute keys listed in
9580 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9581 (@pxref{Substitutes}).
9583 @vindex %default-authorized-guix-keys
9584 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9585 The list of authorized key files for archive imports, as a list of
9586 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9587 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9589 @item @code{use-substitutes?} (default: @code{#t})
9590 Whether to use substitutes.
9592 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9593 The list of URLs where to look for substitutes by default.
9595 @item @code{max-silent-time} (default: @code{0})
9596 @itemx @code{timeout} (default: @code{0})
9597 The number of seconds of silence and the number of seconds of activity,
9598 respectively, after which a build process times out. A value of zero
9599 disables the timeout.
9601 @item @code{extra-options} (default: @code{'()})
9602 List of extra command-line options for @command{guix-daemon}.
9604 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9605 File where @command{guix-daemon}'s standard output and standard error
9608 @item @code{lsof} (default: @var{lsof})
9609 The lsof package to use.
9611 @item @code{http-proxy} (default: @code{#f})
9612 The HTTP proxy used for downloading fixed-output derivations and
9615 @item @code{tmpdir} (default: @code{#f})
9616 A directory path where the @command{guix-daemon} will perform builds.
9621 @deffn {Scheme Procedure} guix-service @var{config}
9622 Return a service that runs the Guix build daemon according to
9626 @deffn {Scheme Procedure} udev-service [#:udev udev]
9627 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9630 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9631 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9635 @defvr {Scheme Variable} %random-seed-file
9636 This is the name of the file where some random bytes are saved by
9637 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9638 It defaults to @file{/var/lib/random-seed}.
9643 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9644 @cindex keyboard layout
9645 Return a service to load console keymaps from @var{files} using
9646 @command{loadkeys} command. Most likely, you want to load some default
9647 keymap, which can be done like this:
9650 (console-keymap-service "dvorak")
9653 Or, for example, for a Swedish keyboard, you may need to combine
9654 the following keymaps:
9656 (console-keymap-service "se-lat6" "se-fi-lat6")
9659 Also you can specify a full file name (or file names) of your keymap(s).
9660 See @code{man loadkeys} for details.
9666 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9668 Run @var{gpm}, the general-purpose mouse daemon, with the given
9669 command-line @var{options}. GPM allows users to use the mouse in the console,
9670 notably to select, copy, and paste text. The default value of @var{options}
9671 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9673 This service is not part of @var{%base-services}.
9676 @anchor{guix-publish-service-type}
9677 @deffn {Scheme Variable} guix-publish-service-type
9678 This is the service type for @command{guix publish} (@pxref{Invoking
9679 guix publish}). Its value must be a @code{guix-configuration}
9680 object, as described below.
9682 This assumes that @file{/etc/guix} already contains a signing key pair as
9683 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9684 archive}). If that is not the case, the service will fail to start.
9687 @deftp {Data Type} guix-publish-configuration
9688 Data type representing the configuration of the @code{guix publish}
9692 @item @code{guix} (default: @code{guix})
9693 The Guix package to use.
9695 @item @code{port} (default: @code{80})
9696 The TCP port to listen for connections.
9698 @item @code{host} (default: @code{"localhost"})
9699 The host (and thus, network interface) to listen to. Use
9700 @code{"0.0.0.0"} to listen on all the network interfaces.
9702 @item @code{compression-level} (default: @code{3})
9703 The gzip compression level at which substitutes are compressed. Use
9704 @code{0} to disable compression altogether, and @code{9} to get the best
9705 compression ratio at the expense of increased CPU usage.
9707 @item @code{nar-path} (default: @code{"nar"})
9708 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9709 publish, @code{--nar-path}}, for details.
9711 @item @code{cache} (default: @code{#f})
9712 When it is @code{#f}, disable caching and instead generate archives on
9713 demand. Otherwise, this should be the name of a directory---e.g.,
9714 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9715 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9716 @option{--cache}}, for more information on the tradeoffs involved.
9718 @item @code{workers} (default: @code{#f})
9719 When it is an integer, this is the number of worker threads used for
9720 caching; when @code{#f}, the number of processors is used.
9721 @xref{Invoking guix publish, @option{--workers}}, for more information.
9723 @item @code{ttl} (default: @code{#f})
9724 When it is an integer, this denotes the @dfn{time-to-live} of the
9725 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9730 @anchor{rngd-service}
9731 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9732 [#:device "/dev/hwrng"]
9733 Return a service that runs the @command{rngd} program from @var{rng-tools}
9734 to add @var{device} to the kernel's entropy pool. The service will fail if
9735 @var{device} does not exist.
9738 @anchor{pam-limits-service}
9739 @cindex session limits
9742 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9744 Return a service that installs a configuration file for the
9745 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9746 @code{pam_limits} module}. The procedure optionally takes a list of
9747 @code{pam-limits-entry} values, which can be used to specify
9748 @code{ulimit} limits and nice priority limits to user sessions.
9750 The following limits definition sets two hard and soft limits for all
9751 login sessions of users in the @code{realtime} group:
9756 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9757 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9760 The first entry increases the maximum realtime priority for
9761 non-privileged processes; the second entry lifts any restriction of the
9762 maximum address space that can be locked in memory. These settings are
9763 commonly used for real-time audio systems.
9766 @node Scheduled Job Execution
9767 @subsubsection Scheduled Job Execution
9771 @cindex scheduling jobs
9772 The @code{(gnu services mcron)} module provides an interface to
9773 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9774 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9775 Unix @command{cron} daemon; the main difference is that it is
9776 implemented in Guile Scheme, which provides a lot of flexibility when
9777 specifying the scheduling of jobs and their actions.
9779 The example below defines an operating system that runs the
9780 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9781 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9782 well as the @command{mkid} command on behalf of an unprivileged user
9783 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9784 gexps to introduce job definitions that are passed to mcron
9785 (@pxref{G-Expressions}).
9788 (use-modules (guix) (gnu) (gnu services mcron))
9789 (use-package-modules base idutils)
9791 (define updatedb-job
9792 ;; Run 'updatedb' at 3AM every day. Here we write the
9793 ;; job's action as a Scheme procedure.
9794 #~(job '(next-hour '(3))
9796 (execl (string-append #$findutils "/bin/updatedb")
9798 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9800 (define garbage-collector-job
9801 ;; Collect garbage 5 minutes after midnight every day.
9802 ;; The job's action is a shell command.
9803 #~(job "5 0 * * *" ;Vixie cron syntax
9807 ;; Update the index database as user "charlie" at 12:15PM
9808 ;; and 19:15PM. This runs from the user's home directory.
9809 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9810 (string-append #$idutils "/bin/mkid src")
9815 (services (cons (mcron-service (list garbage-collector-job
9821 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9822 for more information on mcron job specifications. Below is the
9823 reference of the mcron service.
9825 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9826 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9827 list of gexps denoting mcron job specifications.
9829 This is a shorthand for:
9831 (service mcron-service-type
9832 (mcron-configuration (mcron mcron) (jobs jobs)))
9836 @defvr {Scheme Variable} mcron-service-type
9837 This is the type of the @code{mcron} service, whose value is an
9838 @code{mcron-configuration} object.
9840 This service type can be the target of a service extension that provides
9841 it additional job specifications (@pxref{Service Composition}). In
9842 other words, it is possible to define services that provide additional
9846 @deftp {Data Type} mcron-configuration
9847 Data type representing the configuration of mcron.
9850 @item @code{mcron} (default: @var{mcron2})
9851 The mcron package to use.
9854 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9855 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9856 specifications,, mcron, GNU@tie{}mcron}).
9862 @subsubsection Log Rotation
9865 @cindex log rotation
9867 Log files such as those found in @file{/var/log} tend to grow endlessly,
9868 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9869 their contents in separate files, possibly compressed. The @code{(gnu
9870 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9871 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9873 The example below defines an operating system that provides log rotation
9874 with the default settings, for commonly encountered log files.
9877 (use-modules (guix) (gnu))
9878 (use-service-modules admin mcron)
9879 (use-package-modules base idutils)
9883 (services (cons* (mcron-service)
9884 (service rottlog-service-type)
9888 @defvr {Scheme Variable} rottlog-service-type
9889 This is the type of the Rottlog service, whose value is a
9890 @code{rottlog-configuration} object.
9892 Other services can extend this one with new @code{log-rotation} objects
9893 (see below), thereby augmenting the set of files to be rotated.
9895 This service type can define mcron jobs (@pxref{Scheduled Job
9896 Execution}) to run the rottlog service.
9899 @deftp {Data Type} rottlog-configuration
9900 Data type representing the configuration of rottlog.
9903 @item @code{rottlog} (default: @code{rottlog})
9904 The Rottlog package to use.
9906 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9907 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9908 rottlog, GNU Rot[t]log Manual}).
9910 @item @code{rotations} (default: @code{%default-rotations})
9911 A list of @code{log-rotation} objects as defined below.
9914 This is a list of gexps where each gexp corresponds to an mcron job
9915 specification (@pxref{Scheduled Job Execution}).
9919 @deftp {Data Type} log-rotation
9920 Data type representing the rotation of a group of log files.
9922 Taking an example from the Rottlog manual (@pxref{Period Related File
9923 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
9929 (files '("/var/log/apache/*"))
9930 (options '("storedir apache-archives"
9936 The list of fields is as follows:
9939 @item @code{frequency} (default: @code{'weekly})
9940 The log rotation frequency, a symbol.
9943 The list of files or file glob patterns to rotate.
9945 @item @code{options} (default: @code{'()})
9946 The list of rottlog options for this rotation (@pxref{Configuration
9947 parameters,,, rottlog, GNU Rot[t]lg Manual}).
9949 @item @code{post-rotate} (default: @code{#f})
9950 Either @code{#f} or a gexp to execute once the rotation has completed.
9954 @defvr {Scheme Variable} %default-rotations
9955 Specifies weekly rotation of @var{%rotated-files} and
9956 a couple of other files.
9959 @defvr {Scheme Variable} %rotated-files
9960 The list of syslog-controlled files to be rotated. By default it is:
9961 @code{'("/var/log/messages" "/var/log/secure")}.
9964 @node Networking Services
9965 @subsubsection Networking Services
9967 The @code{(gnu services networking)} module provides services to configure
9968 the network interface.
9970 @cindex DHCP, networking service
9971 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9972 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9973 Protocol (DHCP) client, on all the non-loopback network interfaces.
9976 @defvr {Scheme Variable} static-networking-service-type
9977 This is the type for statically-configured network interfaces.
9978 @c TODO Document <static-networking> data structures.
9981 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9982 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9983 Return a service that starts @var{interface} with address @var{ip}. If
9984 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9985 it must be a string specifying the default network gateway.
9987 This procedure can be called several times, one for each network
9988 interface of interest. Behind the scenes what it does is extend
9989 @code{static-networking-service-type} with additional network interfaces
9996 @cindex network management
9997 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9998 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9999 management daemon that aims to simplify wired and wireless networking.
10001 This service adds the @var{wicd} package to the global profile, providing
10002 several commands to interact with the daemon and configure networking:
10003 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
10004 and @command{wicd-curses} user interfaces.
10007 @cindex NetworkManager
10009 @defvr {Scheme Variable} network-manager-service-type
10010 This is the service type for the
10011 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
10012 service. The value for this service type is a
10013 @code{network-manager-configuration} record.
10015 This service is part of @code{%desktop-services} (@pxref{Desktop
10019 @deftp {Data Type} network-manager-configuration
10020 Data type representing the configuration of NetworkManager.
10023 @item @code{network-manager} (default: @code{network-manager})
10024 The NetworkManager package to use.
10026 @item @code{dns} (default: @code{"default"})
10027 Processing mode for DNS, which affects how NetworkManager uses the
10028 @code{resolv.conf} configuration file.
10032 NetworkManager will update @code{resolv.conf} to reflect the nameservers
10033 provided by currently active connections.
10036 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
10037 using a "split DNS" configuration if you are connected to a VPN, and
10038 then update @code{resolv.conf} to point to the local nameserver.
10041 NetworkManager will not modify @code{resolv.conf}.
10048 @deffn {Scheme Variable} connman-service-type
10049 This is the service type to run @url{https://01.org/connman,Connman},
10050 a network connection manager.
10052 Its value must be an
10053 @code{connman-configuration} record as in this example:
10056 (service connman-service-type
10057 (connman-configuration
10058 (disable-vpn? #t)))
10061 See below for details about @code{connman-configuration}.
10064 @deftp {Data Type} connman-configuration
10065 Data Type representing the configuration of connman.
10068 @item @code{connman} (default: @var{connman})
10069 The connman package to use.
10071 @item @code{disable-vpn?} (default: @code{#f})
10072 When true, enable connman's vpn plugin.
10076 @cindex WPA Supplicant
10077 @defvr {Scheme Variable} wpa-supplicant-service-type
10078 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
10079 supplicant}, an authentication daemon required to authenticate against
10080 encrypted WiFi or ethernet networks. It is configured to listen for
10083 The value of this service is the @code{wpa-supplicant} package to use.
10084 Thus, it can be instantiated like this:
10087 (use-modules (gnu services networking))
10089 (service wpa-supplicant-service-type)
10094 @cindex real time clock
10095 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
10096 [#:servers @var{%ntp-servers}] @
10097 [#:allow-large-adjustment? #f]
10098 Return a service that runs the daemon from @var{ntp}, the
10099 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
10100 keep the system clock synchronized with that of @var{servers}.
10101 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
10102 make an initial adjustment of more than 1,000 seconds.
10105 @defvr {Scheme Variable} %ntp-servers
10106 List of host names used as the default NTP servers.
10110 @deffn {Scheme variable} inetd-service-type
10111 This service runs the @command{inetd} (@pxref{inetd invocation,,,
10112 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
10113 connections on internet sockets, and lazily starts the specified server
10114 program when a connection is made on one of these sockets.
10116 The value of this service is an @code{inetd-configuration} object. The
10117 following example configures the @command{inetd} daemon to provide the
10118 built-in @command{echo} service, as well as an smtp service which
10119 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
10120 gateway @code{hostname}:
10125 (inetd-configuration
10129 (socket-type 'stream)
10136 (socket-type 'stream)
10140 (program (file-append openssh "/bin/ssh"))
10142 '("ssh" "-qT" "-i" "/path/to/ssh_key"
10143 "-W" "smtp-server:25" "user@@hostname")))))
10146 See below for more details about @code{inetd-configuration}.
10149 @deftp {Data Type} inetd-configuration
10150 Data type representing the configuration of @command{inetd}.
10153 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
10154 The @command{inetd} executable to use.
10156 @item @code{entries} (default: @code{'()})
10157 A list of @command{inetd} service entries. Each entry should be created
10158 by the @code{inetd-entry} constructor.
10162 @deftp {Data Type} inetd-entry
10163 Data type representing an entry in the @command{inetd} configuration.
10164 Each entry corresponds to a socket where @command{inetd} will listen for
10168 @item @code{node} (default: @code{#f})
10169 Optional string, a comma-separated list of local addresses
10170 @command{inetd} should use when listening for this service.
10171 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
10172 description of all options.
10174 A string, the name must correspond to an entry in @code{/etc/services}.
10175 @item @code{socket-type}
10176 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
10178 @item @code{protocol}
10179 A string, must correspond to an entry in @code{/etc/protocols}.
10180 @item @code{wait?} (default: @code{#t})
10181 Whether @command{inetd} should wait for the server to exit before
10182 listening to new service requests.
10184 A string containing the user (and, optionally, group) name of the user
10185 as whom the server should run. The group name can be specified in a
10186 suffix, separated by a colon or period, i.e. @code{"user"},
10187 @code{"user:group"} or @code{"user.group"}.
10188 @item @code{program} (default: @code{"internal"})
10189 The server program which will serve the requests, or @code{"internal"}
10190 if @command{inetd} should use a built-in service.
10191 @item @code{arguments} (default: @code{'()})
10192 A list strings or file-like objects, which are the server program's
10193 arguments, starting with the zeroth argument, i.e. the name of the
10194 program itself. For @command{inetd}'s internal services, this entry
10195 must be @code{'()} or @code{'("internal")}.
10198 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
10199 detailed discussion of each configuration field.
10203 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
10204 Return a service to run the @uref{https://torproject.org, Tor} anonymous
10207 The daemon runs as the @code{tor} unprivileged user. It is passed
10208 @var{config-file}, a file-like object, with an additional @code{User tor} line
10209 and lines for hidden services added via @code{tor-hidden-service}. Run
10210 @command{man tor} for information about the configuration file.
10213 @cindex hidden service
10214 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
10215 Define a new Tor @dfn{hidden service} called @var{name} and implementing
10216 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
10219 '((22 "127.0.0.1:22")
10220 (80 "127.0.0.1:8080"))
10223 In this example, port 22 of the hidden service is mapped to local port 22, and
10224 port 80 is mapped to local port 8080.
10226 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
10227 the @file{hostname} file contains the @code{.onion} host name for the hidden
10230 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
10231 project's documentation} for more information.
10234 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
10235 [#:interface "127.0.0.1"] [#:port 6667] @
10236 [#:extra-settings ""]
10237 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
10238 acts as a gateway between IRC and chat networks.
10240 The daemon will listen to the interface corresponding to the IP address
10241 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
10242 local clients can connect, whereas @code{0.0.0.0} means that connections can
10243 come from any networking interface.
10245 In addition, @var{extra-settings} specifies a string to append to the
10246 configuration file.
10249 Furthermore, @code{(gnu services ssh)} provides the following services.
10253 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10254 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10255 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10256 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10257 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10258 [#:public-key-authentication? #t] [#:initialize? #t]
10259 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10260 @var{host-key} must designate a file containing the host key, and readable
10263 When @var{daemonic?} is true, @command{lshd} will detach from the
10264 controlling terminal and log its output to syslogd, unless one sets
10265 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10266 depend on existence of syslogd service. When @var{pid-file?} is true,
10267 @command{lshd} writes its PID to the file called @var{pid-file}.
10269 When @var{initialize?} is true, automatically create the seed and host key
10270 upon service activation if they do not exist yet. This may take long and
10271 require interaction.
10273 When @var{initialize?} is false, it is up to the user to initialize the
10274 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10275 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10276 basics,,, lsh, LSH Manual}).
10278 When @var{interfaces} is empty, lshd listens for connections on all the
10279 network interfaces; otherwise, @var{interfaces} must be a list of host names
10282 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10283 passwords, and @var{root-login?} specifies whether to accept log-ins as
10286 The other options should be self-descriptive.
10291 @deffn {Scheme Variable} openssh-service-type
10292 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10293 shell daemon, @command{sshd}. Its value must be an
10294 @code{openssh-configuration} record as in this example:
10297 (service openssh-service-type
10298 (openssh-configuration
10299 (x11-forwarding? #t)
10300 (permit-root-login 'without-password)
10302 `(("alice" ,(local-file "alice.pub"))
10303 ("bob" ,(local-file "bob.pub"))))))
10306 See below for details about @code{openssh-configuration}.
10308 This service can be extended with extra authorized keys, as in this
10312 (service-extension openssh-service-type
10313 (const `(("charlie"
10314 ,(local-file "charlie.pub")))))
10318 @deftp {Data Type} openssh-configuration
10319 This is the configuration record for OpenSSH's @command{sshd}.
10322 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10323 Name of the file where @command{sshd} writes its PID.
10325 @item @code{port-number} (default: @code{22})
10326 TCP port on which @command{sshd} listens for incoming connections.
10328 @item @code{permit-root-login} (default: @code{#f})
10329 This field determines whether and when to allow logins as root. If
10330 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10331 If it's the symbol @code{'without-password}, then root logins are
10332 permitted but not with password-based authentication.
10334 @item @code{allow-empty-passwords?} (default: @code{#f})
10335 When true, users with empty passwords may log in. When false, they may
10338 @item @code{password-authentication?} (default: @code{#t})
10339 When true, users may log in with their password. When false, they have
10340 other authentication methods.
10342 @item @code{public-key-authentication?} (default: @code{#t})
10343 When true, users may log in using public key authentication. When
10344 false, users have to use other authentication method.
10346 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10347 This is used only by protocol version 2.
10349 @item @code{x11-forwarding?} (default: @code{#f})
10350 When true, forwarding of X11 graphical client connections is
10351 enabled---in other words, @command{ssh} options @option{-X} and
10352 @option{-Y} will work.
10354 @item @code{challenge-response-authentication?} (default: @code{#f})
10355 Specifies whether challenge response authentication is allowed (e.g. via
10358 @item @code{use-pam?} (default: @code{#t})
10359 Enables the Pluggable Authentication Module interface. If set to
10360 @code{#t}, this will enable PAM authentication using
10361 @code{challenge-response-authentication?} and
10362 @code{password-authentication?}, in addition to PAM account and session
10363 module processing for all authentication types.
10365 Because PAM challenge response authentication usually serves an
10366 equivalent role to password authentication, you should disable either
10367 @code{challenge-response-authentication?} or
10368 @code{password-authentication?}.
10370 @item @code{print-last-log?} (default: @code{#t})
10371 Specifies whether @command{sshd} should print the date and time of the
10372 last user login when a user logs in interactively.
10374 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10375 Configures external subsystems (e.g. file transfer daemon).
10377 This is a list of two-element lists, each of which containing the
10378 subsystem name and a command (with optional arguments) to execute upon
10381 The command @command{internal-sftp} implements an in-process SFTP
10382 server. Alternately, one can specify the @command{sftp-server} command:
10384 (service openssh-service-type
10385 (openssh-configuration
10387 `(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10390 @item @code{authorized-keys} (default: @code{'()})
10391 @cindex authorized keys, SSH
10392 @cindex SSH authorized keys
10393 This is the list of authorized keys. Each element of the list is a user
10394 name followed by one or more file-like objects that represent SSH public
10398 (openssh-configuration
10400 `(("rekado" ,(local-file "rekado.pub"))
10401 ("chris" ,(local-file "chris.pub"))
10402 ("root" ,(local-file "rekado.pub") ,(local-file "chris.pub")))))
10406 registers the specified public keys for user accounts @code{rekado},
10407 @code{chris}, and @code{root}.
10409 Additional authorized keys can be specified @i{via}
10410 @code{service-extension}.
10412 Note that this does @emph{not} interfere with the use of
10413 @file{~/.ssh/authorized_keys}.
10417 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10418 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10419 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10422 For example, to specify a Dropbear service listening on port 1234, add
10423 this call to the operating system's @code{services} field:
10426 (dropbear-service (dropbear-configuration
10427 (port-number 1234)))
10431 @deftp {Data Type} dropbear-configuration
10432 This data type represents the configuration of a Dropbear SSH daemon.
10435 @item @code{dropbear} (default: @var{dropbear})
10436 The Dropbear package to use.
10438 @item @code{port-number} (default: 22)
10439 The TCP port where the daemon waits for incoming connections.
10441 @item @code{syslog-output?} (default: @code{#t})
10442 Whether to enable syslog output.
10444 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10445 File name of the daemon's PID file.
10447 @item @code{root-login?} (default: @code{#f})
10448 Whether to allow @code{root} logins.
10450 @item @code{allow-empty-passwords?} (default: @code{#f})
10451 Whether to allow empty passwords.
10453 @item @code{password-authentication?} (default: @code{#t})
10454 Whether to enable password-based authentication.
10458 @defvr {Scheme Variable} %facebook-host-aliases
10459 This variable contains a string for use in @file{/etc/hosts}
10460 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10461 line contains a entry that maps a known server name of the Facebook
10462 on-line service---e.g., @code{www.facebook.com}---to the local
10463 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10465 This variable is typically used in the @code{hosts-file} field of an
10466 @code{operating-system} declaration (@pxref{operating-system Reference,
10467 @file{/etc/hosts}}):
10470 (use-modules (gnu) (guix))
10473 (host-name "mymachine")
10476 ;; Create a /etc/hosts file with aliases for "localhost"
10477 ;; and "mymachine", as well as for Facebook servers.
10478 (plain-file "hosts"
10479 (string-append (local-host-aliases host-name)
10480 %facebook-host-aliases))))
10483 This mechanism can prevent programs running locally, such as Web
10484 browsers, from accessing Facebook.
10487 The @code{(gnu services avahi)} provides the following definition.
10489 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10490 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10491 [#:ipv6? #t] [#:wide-area? #f] @
10492 [#:domains-to-browse '()] [#:debug? #f]
10493 Return a service that runs @command{avahi-daemon}, a system-wide
10494 mDNS/DNS-SD responder that allows for service discovery and
10495 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10496 extends the name service cache daemon (nscd) so that it can resolve
10497 @code{.local} host names using
10498 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10499 add the @var{avahi} package to the system profile so that commands such as
10500 @command{avahi-browse} are directly usable.
10502 If @var{host-name} is different from @code{#f}, use that as the host name to
10503 publish for this machine; otherwise, use the machine's actual host name.
10505 When @var{publish?} is true, publishing of host names and services is allowed;
10506 in particular, avahi-daemon will publish the machine's host name and IP
10507 address via mDNS on the local network.
10509 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10511 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10515 @deffn {Scheme Variable} openvswitch-service-type
10516 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10517 service, whose value should be an @code{openvswitch-configuration}
10521 @deftp {Data Type} openvswitch-configuration
10522 Data type representing the configuration of Open vSwitch, a multilayer
10523 virtual switch which is designed to enable massive network automation
10524 through programmatic extension.
10527 @item @code{package} (default: @var{openvswitch})
10528 Package object of the Open vSwitch.
10534 @subsubsection X Window
10537 @cindex X Window System
10538 Support for the X Window graphical display system---specifically
10539 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10540 there is no @code{xorg-service} procedure. Instead, the X server is
10541 started by the @dfn{login manager}, currently SLiM.
10543 @deftp {Data Type} sddm-configuration
10544 This is the data type representing the sddm service configuration.
10547 @item @code{display-server} (default: "x11")
10548 Select display server to use for the greeter. Valid values are "x11"
10551 @item @code{numlock} (default: "on")
10552 Valid values are "on", "off" or "none".
10554 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10555 Command to run when halting.
10557 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10558 Command to run when rebooting.
10560 @item @code{theme} (default "maldives")
10561 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10563 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10564 Directory to look for themes.
10566 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10567 Directory to look for faces.
10569 @item @code{default-path} (default "/run/current-system/profile/bin")
10570 Default PATH to use.
10572 @item @code{minimum-uid} (default 1000)
10573 Minimum UID to display in SDDM.
10575 @item @code{maximum-uid} (default 2000)
10576 Maximum UID to display in SDDM
10578 @item @code{remember-last-user?} (default #t)
10579 Remember last user.
10581 @item @code{remember-last-session?} (default #t)
10582 Remember last session.
10584 @item @code{hide-users} (default "")
10585 Usernames to hide from SDDM greeter.
10587 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10588 Users with shells listed will be hidden from the SDDM greeter.
10590 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10591 Script to run before starting a wayland session.
10593 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10594 Directory to look for desktop files starting wayland sessions.
10596 @item @code{xorg-server-path} (default @code{xorg-start-command})
10597 Path to xorg-server.
10599 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10602 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10605 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10606 Script to run after starting xorg-server.
10608 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10609 Script to run before stopping xorg-server.
10611 @item @code{xsession-command} (default: @code{xinitr })
10612 Script to run before starting a X session.
10614 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10615 Directory to look for desktop files starting X sessions.
10617 @item @code{minimum-vt} (default: 7)
10620 @item @code{xserver-arguments} (default "-nolisten tcp")
10621 Arguments to pass to xorg-server.
10623 @item @code{auto-login-user} (default "")
10624 User to use for auto-login.
10626 @item @code{auto-login-session} (default "")
10627 Desktop file to use for auto-login.
10629 @item @code{relogin?} (default #f)
10630 Relogin after logout.
10635 @cindex login manager
10636 @deffn {Scheme Procedure} sddm-service config
10637 Return a service that spawns the SDDM graphical login manager for config of
10638 type @code{<sddm-configuration>}.
10641 (sddm-service (sddm-configuration
10642 (auto-login-user "Alice")
10643 (auto-login-session "xfce.desktop")))
10647 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10648 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10649 [#:theme @var{%default-slim-theme}] @
10650 [#:theme-name @var{%default-slim-theme-name}]
10651 Return a service that spawns the SLiM graphical login manager, which in
10652 turn starts the X display server with @var{startx}, a command as returned by
10653 @code{xorg-start-command}.
10657 SLiM automatically looks for session types described by the @file{.desktop}
10658 files in @file{/run/current-system/profile/share/xsessions} and allows users
10659 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10660 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10661 adding them to the system-wide set of packages automatically makes them
10662 available at the log-in screen.
10664 In addition, @file{~/.xsession} files are honored. When available,
10665 @file{~/.xsession} must be an executable that starts a window manager
10666 and/or other X clients.
10668 When @var{allow-empty-passwords?} is true, allow logins with an empty
10669 password. When @var{auto-login?} is true, log in automatically as
10670 @var{default-user}.
10672 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10673 @var{theme} must be a gexp denoting the name of a directory containing the
10674 theme to use. In that case, @var{theme-name} specifies the name of the
10678 @defvr {Scheme Variable} %default-theme
10679 @defvrx {Scheme Variable} %default-theme-name
10680 The G-Expression denoting the default SLiM theme and its name.
10683 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10684 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10685 Return a derivation that builds a @var{guile} script to start the X server
10686 from @var{xorg-server}. @var{configuration-file} is the server configuration
10687 file or a derivation that builds it; when omitted, the result of
10688 @code{xorg-configuration-file} is used.
10690 Usually the X server is started by a login manager.
10693 @deffn {Scheme Procedure} xorg-configuration-file @
10694 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10695 Return a configuration file for the Xorg server containing search paths for
10696 all the common drivers.
10698 @var{drivers} must be either the empty list, in which case Xorg chooses a
10699 graphics driver automatically, or a list of driver names that will be tried in
10700 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10702 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10703 appropriate screen resolution; otherwise, it must be a list of
10704 resolutions---e.g., @code{((1024 768) (640 480))}.
10706 Last, @var{extra-config} is a list of strings or objects appended to the
10707 @code{text-file*} argument list. It is used to pass extra text to be added
10708 verbatim to the configuration file.
10711 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10712 Add @var{package}, a package for a screen-locker or screen-saver whose
10713 command is @var{program}, to the set of setuid programs and add a PAM entry
10714 for it. For example:
10717 (screen-locker-service xlockmore "xlock")
10720 makes the good ol' XlockMore usable.
10724 @node Printing Services
10725 @subsubsection Printing Services
10727 @cindex printer support with CUPS
10728 The @code{(gnu services cups)} module provides a Guix service definition
10729 for the CUPS printing service. To add printer support to a GuixSD
10730 system, add a @code{cups-service} to the operating system definition:
10732 @deffn {Scheme Variable} cups-service-type
10733 The service type for the CUPS print server. Its value should be a valid
10734 CUPS configuration (see below). To use the default settings, simply
10737 (service cups-service-type)
10741 The CUPS configuration controls the basic things about your CUPS
10742 installation: what interfaces it listens on, what to do if a print job
10743 fails, how much logging to do, and so on. To actually add a printer,
10744 you have to visit the @url{http://localhost:631} URL, or use a tool such
10745 as GNOME's printer configuration services. By default, configuring a
10746 CUPS service will generate a self-signed certificate if needed, for
10747 secure connections to the print server.
10749 Suppose you want to enable the Web interface of CUPS and also add
10750 support for HP printers @i{via} the @code{hplip} package. You can do
10751 that directly, like this (you need to use the @code{(gnu packages cups)}
10755 (service cups-service-type
10756 (cups-configuration
10757 (web-interface? #t)
10759 (list cups-filters hplip))))
10762 The available configuration parameters follow. Each parameter
10763 definition is preceded by its type; for example, @samp{string-list foo}
10764 indicates that the @code{foo} parameter should be specified as a list of
10765 strings. There is also a way to specify the configuration as a string,
10766 if you have an old @code{cupsd.conf} file that you want to port over
10767 from some other system; see the end for more details.
10769 @c The following documentation was initially generated by
10770 @c (generate-documentation) in (gnu services cups). Manually maintained
10771 @c documentation is better, so we shouldn't hesitate to edit below as
10772 @c needed. However if the change you want to make to this documentation
10773 @c can be done in an automated way, it's probably easier to change
10774 @c (generate-documentation) than to make it below and have to deal with
10775 @c the churn as CUPS updates.
10778 Available @code{cups-configuration} fields are:
10780 @deftypevr {@code{cups-configuration} parameter} package cups
10784 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10785 Drivers and other extensions to the CUPS package.
10788 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10789 Configuration of where to write logs, what directories to use for print
10790 spools, and related privileged configuration parameters.
10792 Available @code{files-configuration} fields are:
10794 @deftypevr {@code{files-configuration} parameter} log-location access-log
10795 Defines the access log filename. Specifying a blank filename disables
10796 access log generation. The value @code{stderr} causes log entries to be
10797 sent to the standard error file when the scheduler is running in the
10798 foreground, or to the system log daemon when run in the background. The
10799 value @code{syslog} causes log entries to be sent to the system log
10800 daemon. The server name may be included in filenames using the string
10801 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10803 Defaults to @samp{"/var/log/cups/access_log"}.
10806 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10807 Where CUPS should cache data.
10809 Defaults to @samp{"/var/cache/cups"}.
10812 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10813 Specifies the permissions for all configuration files that the scheduler
10816 Note that the permissions for the printers.conf file are currently
10817 masked to only allow access from the scheduler user (typically root).
10818 This is done because printer device URIs sometimes contain sensitive
10819 authentication information that should not be generally known on the
10820 system. There is no way to disable this security feature.
10822 Defaults to @samp{"0640"}.
10825 @deftypevr {@code{files-configuration} parameter} log-location error-log
10826 Defines the error log filename. Specifying a blank filename disables
10827 access log generation. The value @code{stderr} causes log entries to be
10828 sent to the standard error file when the scheduler is running in the
10829 foreground, or to the system log daemon when run in the background. The
10830 value @code{syslog} causes log entries to be sent to the system log
10831 daemon. The server name may be included in filenames using the string
10832 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10834 Defaults to @samp{"/var/log/cups/error_log"}.
10837 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10838 Specifies which errors are fatal, causing the scheduler to exit. The
10843 No errors are fatal.
10846 All of the errors below are fatal.
10849 Browsing initialization errors are fatal, for example failed connections
10850 to the DNS-SD daemon.
10853 Configuration file syntax errors are fatal.
10856 Listen or Port errors are fatal, except for IPv6 failures on the
10857 loopback or @code{any} addresses.
10860 Log file creation or write errors are fatal.
10863 Bad startup file permissions are fatal, for example shared TLS
10864 certificate and key files with world-read permissions.
10867 Defaults to @samp{"all -browse"}.
10870 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10871 Specifies whether the file pseudo-device can be used for new printer
10872 queues. The URI @uref{file:///dev/null} is always allowed.
10874 Defaults to @samp{#f}.
10877 @deftypevr {@code{files-configuration} parameter} string group
10878 Specifies the group name or ID that will be used when executing external
10881 Defaults to @samp{"lp"}.
10884 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10885 Specifies the permissions for all log files that the scheduler writes.
10887 Defaults to @samp{"0644"}.
10890 @deftypevr {@code{files-configuration} parameter} log-location page-log
10891 Defines the page log filename. Specifying a blank filename disables
10892 access log generation. The value @code{stderr} causes log entries to be
10893 sent to the standard error file when the scheduler is running in the
10894 foreground, or to the system log daemon when run in the background. The
10895 value @code{syslog} causes log entries to be sent to the system log
10896 daemon. The server name may be included in filenames using the string
10897 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10899 Defaults to @samp{"/var/log/cups/page_log"}.
10902 @deftypevr {@code{files-configuration} parameter} string remote-root
10903 Specifies the username that is associated with unauthenticated accesses
10904 by clients claiming to be the root user. The default is @code{remroot}.
10906 Defaults to @samp{"remroot"}.
10909 @deftypevr {@code{files-configuration} parameter} file-name request-root
10910 Specifies the directory that contains print jobs and other HTTP request
10913 Defaults to @samp{"/var/spool/cups"}.
10916 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10917 Specifies the level of security sandboxing that is applied to print
10918 filters, backends, and other child processes of the scheduler; either
10919 @code{relaxed} or @code{strict}. This directive is currently only
10920 used/supported on macOS.
10922 Defaults to @samp{strict}.
10925 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10926 Specifies the location of TLS certificates and private keys. CUPS will
10927 look for public and private keys in this directory: a @code{.crt} files
10928 for PEM-encoded certificates and corresponding @code{.key} files for
10929 PEM-encoded private keys.
10931 Defaults to @samp{"/etc/cups/ssl"}.
10934 @deftypevr {@code{files-configuration} parameter} file-name server-root
10935 Specifies the directory containing the server configuration files.
10937 Defaults to @samp{"/etc/cups"}.
10940 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10941 Specifies whether the scheduler calls fsync(2) after writing
10942 configuration or state files.
10944 Defaults to @samp{#f}.
10947 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10948 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10951 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10952 Specifies the directory where temporary files are stored.
10954 Defaults to @samp{"/var/spool/cups/tmp"}.
10957 @deftypevr {@code{files-configuration} parameter} string user
10958 Specifies the user name or ID that is used when running external
10961 Defaults to @samp{"lp"}.
10965 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10966 Specifies the logging level for the AccessLog file. The @code{config}
10967 level logs when printers and classes are added, deleted, or modified and
10968 when configuration files are accessed or updated. The @code{actions}
10969 level logs when print jobs are submitted, held, released, modified, or
10970 canceled, and any of the conditions for @code{config}. The @code{all}
10971 level logs all requests.
10973 Defaults to @samp{actions}.
10976 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10977 Specifies whether to purge job history data automatically when it is no
10978 longer required for quotas.
10980 Defaults to @samp{#f}.
10983 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10984 Specifies which protocols to use for local printer sharing.
10986 Defaults to @samp{dnssd}.
10989 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10990 Specifies whether the CUPS web interface is advertised.
10992 Defaults to @samp{#f}.
10995 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10996 Specifies whether shared printers are advertised.
10998 Defaults to @samp{#f}.
11001 @deftypevr {@code{cups-configuration} parameter} string classification
11002 Specifies the security classification of the server. Any valid banner
11003 name can be used, including "classified", "confidential", "secret",
11004 "topsecret", and "unclassified", or the banner can be omitted to disable
11005 secure printing functions.
11007 Defaults to @samp{""}.
11010 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
11011 Specifies whether users may override the classification (cover page) of
11012 individual print jobs using the @code{job-sheets} option.
11014 Defaults to @samp{#f}.
11017 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
11018 Specifies the default type of authentication to use.
11020 Defaults to @samp{Basic}.
11023 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
11024 Specifies whether encryption will be used for authenticated requests.
11026 Defaults to @samp{Required}.
11029 @deftypevr {@code{cups-configuration} parameter} string default-language
11030 Specifies the default language to use for text and web content.
11032 Defaults to @samp{"en"}.
11035 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
11036 Specifies the default paper size for new print queues. @samp{"Auto"}
11037 uses a locale-specific default, while @samp{"None"} specifies there is
11038 no default paper size. Specific size names are typically
11039 @samp{"Letter"} or @samp{"A4"}.
11041 Defaults to @samp{"Auto"}.
11044 @deftypevr {@code{cups-configuration} parameter} string default-policy
11045 Specifies the default access policy to use.
11047 Defaults to @samp{"default"}.
11050 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
11051 Specifies whether local printers are shared by default.
11053 Defaults to @samp{#t}.
11056 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
11057 Specifies the delay for updating of configuration and state files, in
11058 seconds. A value of 0 causes the update to happen as soon as possible,
11059 typically within a few milliseconds.
11061 Defaults to @samp{30}.
11064 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
11065 Specifies what to do when an error occurs. Possible values are
11066 @code{abort-job}, which will discard the failed print job;
11067 @code{retry-job}, which will retry the job at a later time;
11068 @code{retry-this-job}, which retries the failed job immediately; and
11069 @code{stop-printer}, which stops the printer.
11071 Defaults to @samp{stop-printer}.
11074 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
11075 Specifies the maximum cost of filters that are run concurrently, which
11076 can be used to minimize disk, memory, and CPU resource problems. A
11077 limit of 0 disables filter limiting. An average print to a
11078 non-PostScript printer needs a filter limit of about 200. A PostScript
11079 printer needs about half that (100). Setting the limit below these
11080 thresholds will effectively limit the scheduler to printing a single job
11083 Defaults to @samp{0}.
11086 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
11087 Specifies the scheduling priority of filters that are run to print a
11088 job. The nice value ranges from 0, the highest priority, to 19, the
11091 Defaults to @samp{0}.
11094 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
11095 Specifies whether to do reverse lookups on connecting clients. The
11096 @code{double} setting causes @code{cupsd} to verify that the hostname
11097 resolved from the address matches one of the addresses returned for that
11098 hostname. Double lookups also prevent clients with unregistered
11099 addresses from connecting to your server. Only set this option to
11100 @code{#t} or @code{double} if absolutely required.
11102 Defaults to @samp{#f}.
11105 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
11106 Specifies the number of seconds to wait before killing the filters and
11107 backend associated with a canceled or held job.
11109 Defaults to @samp{30}.
11112 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
11113 Specifies the interval between retries of jobs in seconds. This is
11114 typically used for fax queues but can also be used with normal print
11115 queues whose error policy is @code{retry-job} or
11116 @code{retry-current-job}.
11118 Defaults to @samp{30}.
11121 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
11122 Specifies the number of retries that are done for jobs. This is
11123 typically used for fax queues but can also be used with normal print
11124 queues whose error policy is @code{retry-job} or
11125 @code{retry-current-job}.
11127 Defaults to @samp{5}.
11130 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
11131 Specifies whether to support HTTP keep-alive connections.
11133 Defaults to @samp{#t}.
11136 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
11137 Specifies how long an idle client connection remains open, in seconds.
11139 Defaults to @samp{30}.
11142 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
11143 Specifies the maximum size of print files, IPP requests, and HTML form
11144 data. A limit of 0 disables the limit check.
11146 Defaults to @samp{0}.
11149 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
11150 Listens on the specified interfaces for connections. Valid values are
11151 of the form @var{address}:@var{port}, where @var{address} is either an
11152 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
11153 indicate all addresses. Values can also be file names of local UNIX
11154 domain sockets. The Listen directive is similar to the Port directive
11155 but allows you to restrict access to specific interfaces or networks.
11158 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
11159 Specifies the number of pending connections that will be allowed. This
11160 normally only affects very busy servers that have reached the MaxClients
11161 limit, but can also be triggered by large numbers of simultaneous
11162 connections. When the limit is reached, the operating system will
11163 refuse additional connections until the scheduler can accept the pending
11166 Defaults to @samp{128}.
11169 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
11170 Specifies a set of additional access controls.
11172 Available @code{location-access-controls} fields are:
11174 @deftypevr {@code{location-access-controls} parameter} file-name path
11175 Specifies the URI path to which the access control applies.
11178 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
11179 Access controls for all access to this path, in the same format as the
11180 @code{access-controls} of @code{operation-access-control}.
11182 Defaults to @samp{()}.
11185 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
11186 Access controls for method-specific access to this path.
11188 Defaults to @samp{()}.
11190 Available @code{method-access-controls} fields are:
11192 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
11193 If @code{#t}, apply access controls to all methods except the listed
11194 methods. Otherwise apply to only the listed methods.
11196 Defaults to @samp{#f}.
11199 @deftypevr {@code{method-access-controls} parameter} method-list methods
11200 Methods to which this access control applies.
11202 Defaults to @samp{()}.
11205 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
11206 Access control directives, as a list of strings. Each string should be
11207 one directive, such as "Order allow,deny".
11209 Defaults to @samp{()}.
11214 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
11215 Specifies the number of debugging messages that are retained for logging
11216 if an error occurs in a print job. Debug messages are logged regardless
11217 of the LogLevel setting.
11219 Defaults to @samp{100}.
11222 @deftypevr {@code{cups-configuration} parameter} log-level log-level
11223 Specifies the level of logging for the ErrorLog file. The value
11224 @code{none} stops all logging while @code{debug2} logs everything.
11226 Defaults to @samp{info}.
11229 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
11230 Specifies the format of the date and time in the log files. The value
11231 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
11233 Defaults to @samp{standard}.
11236 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
11237 Specifies the maximum number of simultaneous clients that are allowed by
11240 Defaults to @samp{100}.
11243 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
11244 Specifies the maximum number of simultaneous clients that are allowed
11245 from a single address.
11247 Defaults to @samp{100}.
11250 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
11251 Specifies the maximum number of copies that a user can print of each
11254 Defaults to @samp{9999}.
11257 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
11258 Specifies the maximum time a job may remain in the @code{indefinite}
11259 hold state before it is canceled. A value of 0 disables cancellation of
11262 Defaults to @samp{0}.
11265 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
11266 Specifies the maximum number of simultaneous jobs that are allowed. Set
11267 to 0 to allow an unlimited number of jobs.
11269 Defaults to @samp{500}.
11272 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
11273 Specifies the maximum number of simultaneous jobs that are allowed per
11274 printer. A value of 0 allows up to MaxJobs jobs per printer.
11276 Defaults to @samp{0}.
11279 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
11280 Specifies the maximum number of simultaneous jobs that are allowed per
11281 user. A value of 0 allows up to MaxJobs jobs per user.
11283 Defaults to @samp{0}.
11286 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11287 Specifies the maximum time a job may take to print before it is
11288 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11290 Defaults to @samp{10800}.
11293 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11294 Specifies the maximum size of the log files before they are rotated, in
11295 bytes. The value 0 disables log rotation.
11297 Defaults to @samp{1048576}.
11300 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11301 Specifies the maximum amount of time to allow between files in a
11302 multiple file print job, in seconds.
11304 Defaults to @samp{300}.
11307 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11308 Specifies the format of PageLog lines. Sequences beginning with percent
11309 (@samp{%}) characters are replaced with the corresponding information,
11310 while all other characters are copied literally. The following percent
11311 sequences are recognized:
11315 insert a single percent character
11318 insert the value of the specified IPP attribute
11321 insert the number of copies for the current page
11324 insert the current page number
11327 insert the current date and time in common log format
11333 insert the printer name
11336 insert the username
11339 A value of the empty string disables page logging. The string @code{%p
11340 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11341 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11344 Defaults to @samp{""}.
11347 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11348 Passes the specified environment variable(s) to child processes; a list
11351 Defaults to @samp{()}.
11354 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11355 Specifies named access control policies.
11357 Available @code{policy-configuration} fields are:
11359 @deftypevr {@code{policy-configuration} parameter} string name
11360 Name of the policy.
11363 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11364 Specifies an access list for a job's private values. @code{@@ACL} maps
11365 to the printer's requesting-user-name-allowed or
11366 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11367 owner. @code{@@SYSTEM} maps to the groups listed for the
11368 @code{system-group} field of the @code{files-config} configuration,
11369 which is reified into the @code{cups-files.conf(5)} file. Other
11370 possible elements of the access list include specific user names, and
11371 @code{@@@var{group}} to indicate members of a specific group. The
11372 access list may also be simply @code{all} or @code{default}.
11374 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11377 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11378 Specifies the list of job values to make private, or @code{all},
11379 @code{default}, or @code{none}.
11381 Defaults to @samp{"job-name job-originating-host-name
11382 job-originating-user-name phone"}.
11385 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11386 Specifies an access list for a subscription's private values.
11387 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11388 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11389 owner. @code{@@SYSTEM} maps to the groups listed for the
11390 @code{system-group} field of the @code{files-config} configuration,
11391 which is reified into the @code{cups-files.conf(5)} file. Other
11392 possible elements of the access list include specific user names, and
11393 @code{@@@var{group}} to indicate members of a specific group. The
11394 access list may also be simply @code{all} or @code{default}.
11396 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11399 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11400 Specifies the list of job values to make private, or @code{all},
11401 @code{default}, or @code{none}.
11403 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11404 notify-subscriber-user-name notify-user-data"}.
11407 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11408 Access control by IPP operation.
11410 Defaults to @samp{()}.
11414 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11415 Specifies whether job files (documents) are preserved after a job is
11416 printed. If a numeric value is specified, job files are preserved for
11417 the indicated number of seconds after printing. Otherwise a boolean
11418 value applies indefinitely.
11420 Defaults to @samp{86400}.
11423 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11424 Specifies whether the job history is preserved after a job is printed.
11425 If a numeric value is specified, the job history is preserved for the
11426 indicated number of seconds after printing. If @code{#t}, the job
11427 history is preserved until the MaxJobs limit is reached.
11429 Defaults to @samp{#t}.
11432 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11433 Specifies the amount of time to wait for job completion before
11434 restarting the scheduler.
11436 Defaults to @samp{30}.
11439 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11440 Specifies the maximum amount of memory to use when converting documents
11441 into bitmaps for a printer.
11443 Defaults to @samp{"128m"}.
11446 @deftypevr {@code{cups-configuration} parameter} string server-admin
11447 Specifies the email address of the server administrator.
11449 Defaults to @samp{"root@@localhost.localdomain"}.
11452 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11453 The ServerAlias directive is used for HTTP Host header validation when
11454 clients connect to the scheduler from external interfaces. Using the
11455 special name @code{*} can expose your system to known browser-based DNS
11456 rebinding attacks, even when accessing sites through a firewall. If the
11457 auto-discovery of alternate names does not work, we recommend listing
11458 each alternate name with a ServerAlias directive instead of using
11461 Defaults to @samp{*}.
11464 @deftypevr {@code{cups-configuration} parameter} string server-name
11465 Specifies the fully-qualified host name of the server.
11467 Defaults to @samp{"localhost"}.
11470 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11471 Specifies what information is included in the Server header of HTTP
11472 responses. @code{None} disables the Server header. @code{ProductOnly}
11473 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11474 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11475 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11476 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11477 2.0.0 (@var{uname}) IPP/2.0}.
11479 Defaults to @samp{Minimal}.
11482 @deftypevr {@code{cups-configuration} parameter} string set-env
11483 Set the specified environment variable to be passed to child processes.
11485 Defaults to @samp{"variable value"}.
11488 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11489 Listens on the specified interfaces for encrypted connections. Valid
11490 values are of the form @var{address}:@var{port}, where @var{address} is
11491 either an IPv6 address enclosed in brackets, an IPv4 address, or
11492 @code{*} to indicate all addresses.
11494 Defaults to @samp{()}.
11497 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11498 Sets encryption options. By default, CUPS only supports encryption
11499 using TLS v1.0 or higher using known secure cipher suites. The
11500 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11501 required for some older clients that do not implement newer ones. The
11502 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11503 older clients that do not support TLS v1.0.
11505 Defaults to @samp{()}.
11508 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11509 Specifies whether the scheduler requires clients to strictly adhere to
11510 the IPP specifications.
11512 Defaults to @samp{#f}.
11515 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11516 Specifies the HTTP request timeout, in seconds.
11518 Defaults to @samp{300}.
11522 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11523 Specifies whether the web interface is enabled.
11525 Defaults to @samp{#f}.
11528 At this point you're probably thinking ``oh dear, Guix manual, I like
11529 you but you can stop already with the configuration options''. Indeed.
11530 However, one more point: it could be that you have an existing
11531 @code{cupsd.conf} that you want to use. In that case, you can pass an
11532 @code{opaque-cups-configuration} as the configuration of a
11533 @code{cups-service-type}.
11535 Available @code{opaque-cups-configuration} fields are:
11537 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11541 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11542 The contents of the @code{cupsd.conf}, as a string.
11545 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11546 The contents of the @code{cups-files.conf} file, as a string.
11549 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11550 strings of the same name, you could instantiate a CUPS service like
11554 (service cups-service-type
11555 (opaque-cups-configuration
11556 (cupsd.conf cupsd.conf)
11557 (cups-files.conf cups-files.conf)))
11561 @node Desktop Services
11562 @subsubsection Desktop Services
11564 The @code{(gnu services desktop)} module provides services that are
11565 usually useful in the context of a ``desktop'' setup---that is, on a
11566 machine running a graphical display server, possibly with graphical user
11567 interfaces, etc. It also defines services that provide specific desktop
11568 environments like GNOME and XFCE.
11570 To simplify things, the module defines a variable containing the set of
11571 services that users typically expect on a machine with a graphical
11572 environment and networking:
11574 @defvr {Scheme Variable} %desktop-services
11575 This is a list of services that builds upon @var{%base-services} and
11576 adds or adjusts services for a typical ``desktop'' setup.
11578 In particular, it adds a graphical login manager (@pxref{X Window,
11579 @code{slim-service}}), screen lockers, a network management tool
11580 (@pxref{Networking Services, @code{network-manager-service-type}}), energy and color
11581 management services, the @code{elogind} login and seat manager, the
11582 Polkit privilege service, the GeoClue location service, the
11583 AccountsService daemon that allows authorized users change system
11584 passwords, an NTP client (@pxref{Networking Services}), the Avahi
11585 daemon, and has the name service switch service configured to be able to
11586 use @code{nss-mdns} (@pxref{Name Service Switch, mDNS}).
11589 The @var{%desktop-services} variable can be used as the @code{services}
11590 field of an @code{operating-system} declaration (@pxref{operating-system
11591 Reference, @code{services}}).
11593 Additionally, the @code{gnome-desktop-service} and
11594 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11595 system. To ``add GNOME'' means that system-level services like the
11596 backlight adjustment helpers and the power management utilities are
11597 added to the system, extending @code{polkit} and @code{dbus}
11598 appropriately, allowing GNOME to operate with elevated privileges on a
11599 limited number of special-purpose system interfaces. Additionally,
11600 adding a service made by @code{gnome-desktop-service} adds the GNOME
11601 metapackage to the system profile. Likewise, adding the XFCE service
11602 not only adds the @code{xfce} metapackage to the system profile, but it
11603 also gives the Thunar file manager the ability to open a ``root-mode''
11604 file management window, if the user authenticates using the
11605 administrator's password via the standard polkit graphical interface.
11607 @deffn {Scheme Procedure} gnome-desktop-service
11608 Return a service that adds the @code{gnome} package to the system
11609 profile, and extends polkit with the actions from
11610 @code{gnome-settings-daemon}.
11613 @deffn {Scheme Procedure} xfce-desktop-service
11614 Return a service that adds the @code{xfce} package to the system profile,
11615 and extends polkit with the ability for @code{thunar} to manipulate the
11616 file system as root from within a user session, after the user has
11617 authenticated with the administrator's password.
11620 Because the GNOME and XFCE desktop services pull in so many packages,
11621 the default @code{%desktop-services} variable doesn't include either of
11622 them by default. To add GNOME or XFCE, just @code{cons} them onto
11623 @code{%desktop-services} in the @code{services} field of your
11624 @code{operating-system}:
11627 (use-modules (gnu))
11628 (use-service-modules desktop)
11631 ;; cons* adds items to the list given as its last argument.
11632 (services (cons* (gnome-desktop-service)
11633 (xfce-desktop-service)
11634 %desktop-services))
11638 These desktop environments will then be available as options in the
11639 graphical login window.
11641 The actual service definitions included in @code{%desktop-services} and
11642 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11643 are described below.
11645 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11646 Return a service that runs the ``system bus'', using @var{dbus}, with
11647 support for @var{services}.
11649 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11650 facility. Its system bus is used to allow system services to communicate
11651 and to be notified of system-wide events.
11653 @var{services} must be a list of packages that provide an
11654 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11655 and policy files. For example, to allow avahi-daemon to use the system bus,
11656 @var{services} must be equal to @code{(list avahi)}.
11659 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11660 Return a service that runs the @code{elogind} login and
11661 seat management daemon. @uref{https://github.com/andywingo/elogind,
11662 Elogind} exposes a D-Bus interface that can be used to know which users
11663 are logged in, know what kind of sessions they have open, suspend the
11664 system, inhibit system suspend, reboot the system, and other tasks.
11666 Elogind handles most system-level power events for a computer, for
11667 example suspending the system when a lid is closed, or shutting it down
11668 when the power button is pressed.
11670 The @var{config} keyword argument specifies the configuration for
11671 elogind, and should be the result of an @code{(elogind-configuration
11672 (@var{parameter} @var{value})...)} invocation. Available parameters and
11673 their default values are:
11676 @item kill-user-processes?
11678 @item kill-only-users
11680 @item kill-exclude-users
11682 @item inhibit-delay-max-seconds
11684 @item handle-power-key
11686 @item handle-suspend-key
11688 @item handle-hibernate-key
11690 @item handle-lid-switch
11692 @item handle-lid-switch-docked
11694 @item power-key-ignore-inhibited?
11696 @item suspend-key-ignore-inhibited?
11698 @item hibernate-key-ignore-inhibited?
11700 @item lid-switch-ignore-inhibited?
11702 @item holdoff-timeout-seconds
11706 @item idle-action-seconds
11708 @item runtime-directory-size-percent
11710 @item runtime-directory-size
11714 @item suspend-state
11715 @code{("mem" "standby" "freeze")}
11718 @item hibernate-state
11720 @item hibernate-mode
11721 @code{("platform" "shutdown")}
11722 @item hybrid-sleep-state
11724 @item hybrid-sleep-mode
11725 @code{("suspend" "platform" "shutdown")}
11729 @deffn {Scheme Procedure} accountsservice-service @
11730 [#:accountsservice @var{accountsservice}]
11731 Return a service that runs AccountsService, a system service that can
11732 list available accounts, change their passwords, and so on.
11733 AccountsService integrates with PolicyKit to enable unprivileged users
11734 to acquire the capability to modify their system configuration.
11735 @uref{https://www.freedesktop.org/wiki/Software/AccountsService/, the
11736 accountsservice web site} for more information.
11738 The @var{accountsservice} keyword argument is the @code{accountsservice}
11739 package to expose as a service.
11742 @deffn {Scheme Procedure} polkit-service @
11743 [#:polkit @var{polkit}]
11744 Return a service that runs the
11745 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11746 management service}, which allows system administrators to grant access to
11747 privileged operations in a structured way. By querying the Polkit service, a
11748 privileged system component can know when it should grant additional
11749 capabilities to ordinary users. For example, an ordinary user can be granted
11750 the capability to suspend the system if the user is logged in locally.
11753 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11754 [#:watts-up-pro? #f] @
11755 [#:poll-batteries? #t] @
11756 [#:ignore-lid? #f] @
11757 [#:use-percentage-for-policy? #f] @
11758 [#:percentage-low 10] @
11759 [#:percentage-critical 3] @
11760 [#:percentage-action 2] @
11761 [#:time-low 1200] @
11762 [#:time-critical 300] @
11763 [#:time-action 120] @
11764 [#:critical-power-action 'hybrid-sleep]
11765 Return a service that runs @uref{http://upower.freedesktop.org/,
11766 @command{upowerd}}, a system-wide monitor for power consumption and battery
11767 levels, with the given configuration settings. It implements the
11768 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11772 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11773 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11774 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11775 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11776 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11779 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11780 Return a service that runs @command{colord}, a system service with a D-Bus
11781 interface to manage the color profiles of input and output devices such as
11782 screens and scanners. It is notably used by the GNOME Color Manager graphical
11783 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11784 site} for more information.
11787 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11788 Return a configuration allowing an application to access GeoClue
11789 location data. @var{name} is the Desktop ID of the application, without
11790 the @code{.desktop} part. If @var{allowed?} is true, the application
11791 will have access to location information by default. The boolean
11792 @var{system?} value indicates whether an application is a system component
11793 or not. Finally @var{users} is a list of UIDs of all users for which
11794 this application is allowed location info access. An empty users list
11795 means that all users are allowed.
11798 @defvr {Scheme Variable} %standard-geoclue-applications
11799 The standard list of well-known GeoClue application configurations,
11800 granting authority to the GNOME date-and-time utility to ask for the
11801 current location in order to set the time zone, and allowing the
11802 IceCat and Epiphany web browsers to request location information.
11803 IceCat and Epiphany both query the user before allowing a web page to
11804 know the user's location.
11807 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11808 [#:whitelist '()] @
11809 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11810 [#:submit-data? #f]
11811 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11812 [#:submission-nick "geoclue"] @
11813 [#:applications %standard-geoclue-applications]
11814 Return a service that runs the GeoClue location service. This service
11815 provides a D-Bus interface to allow applications to request access to a
11816 user's physical location, and optionally to add information to online
11817 location databases. See
11818 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11819 web site} for more information.
11822 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}] @
11823 [@w{#:auto-enable? #f}]
11824 Return a service that runs the @command{bluetoothd} daemon, which
11825 manages all the Bluetooth devices and provides a number of D-Bus
11826 interfaces. When AUTO-ENABLE? is true, the bluetooth controller is
11827 powered automatically at boot, which can be useful when using a
11828 bluetooth keyboard or mouse.
11830 Users need to be in the @code{lp} group to access the D-Bus service.
11833 @node Database Services
11834 @subsubsection Database Services
11838 The @code{(gnu services databases)} module provides the following services.
11840 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11841 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11842 [#:port 5432] [#:locale ``en_US.utf8'']
11843 Return a service that runs @var{postgresql}, the PostgreSQL database
11846 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11847 creates a database cluster with @var{locale} as the default
11848 locale, stored in @var{data-directory}. It then listens on @var{port}.
11851 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11852 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11855 The optional @var{config} argument specifies the configuration for
11856 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11859 @deftp {Data Type} mysql-configuration
11860 Data type representing the configuration of @var{mysql-service}.
11863 @item @code{mysql} (default: @var{mariadb})
11864 Package object of the MySQL database server, can be either @var{mariadb}
11867 For MySQL, a temporary root password will be displayed at activation time.
11868 For MariaDB, the root password is empty.
11870 @item @code{port} (default: @code{3306})
11871 TCP port on which the database server listens for incoming connections.
11875 @defvr {Scheme Variable} memcached-service-type
11876 This is the service type for the @uref{https://memcached.org/,
11877 Memcached} service, which provides a distributed in memory cache. The
11878 value for the service type is a @code{memcached-configuration} object.
11882 (service memcached-service-type)
11885 @deftp {Data Type} memcached-configuration
11886 Data type representing the configuration of memcached.
11889 @item @code{memcached} (default: @code{memcached})
11890 The Memcached package to use.
11892 @item @code{interfaces} (default: @code{'("0.0.0.0")})
11893 Network interfaces on which to listen.
11895 @item @code{tcp-port} (default: @code{11211})
11896 Port on which to accept connections on,
11898 @item @code{udp-port} (default: @code{11211})
11899 Port on which to accept UDP connections on, a value of 0 will disable
11900 listening on a UDP socket.
11902 @item @code{additional-options} (default: @code{'()})
11903 Additional command line options to pass to @code{memcached}.
11907 @defvr {Scheme Variable} redis-service-type
11908 This is the service type for the @uref{https://redis.io/, Redis}
11909 key/value store, whose value is a @code{redis-configuration} object.
11912 @deftp {Data Type} redis-configuration
11913 Data type representing the configuration of redis.
11916 @item @code{redis} (default: @code{redis})
11917 The Redis package to use.
11919 @item @code{bind} (default: @code{"127.0.0.1"})
11920 Network interface on which to listen.
11922 @item @code{port} (default: @code{6379})
11923 Port on which to accept connections on, a value of 0 will disable
11924 listening on a TCP socket.
11926 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11927 Directory in which to store the database and related files.
11931 @node Mail Services
11932 @subsubsection Mail Services
11936 The @code{(gnu services mail)} module provides Guix service definitions
11937 for email services: IMAP, POP3, and LMTP servers, as well as mail
11938 transport agents (MTAs). Lots of acronyms! These services are detailed
11939 in the subsections below.
11941 @subsubheading Dovecot Service
11943 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11944 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11947 By default, Dovecot does not need much configuration; the default
11948 configuration object created by @code{(dovecot-configuration)} will
11949 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11950 certificate will be generated for TLS-protected connections, though
11951 Dovecot will also listen on cleartext ports by default. There are a
11952 number of options, though, which mail administrators might need to change,
11953 and as is the case with other services, Guix allows the system
11954 administrator to specify these parameters via a uniform Scheme interface.
11956 For example, to specify that mail is located at @code{maildir~/.mail},
11957 one would instantiate the Dovecot service like this:
11960 (dovecot-service #:config
11961 (dovecot-configuration
11962 (mail-location "maildir:~/.mail")))
11965 The available configuration parameters follow. Each parameter
11966 definition is preceded by its type; for example, @samp{string-list foo}
11967 indicates that the @code{foo} parameter should be specified as a list of
11968 strings. There is also a way to specify the configuration as a string,
11969 if you have an old @code{dovecot.conf} file that you want to port over
11970 from some other system; see the end for more details.
11972 @c The following documentation was initially generated by
11973 @c (generate-documentation) in (gnu services mail). Manually maintained
11974 @c documentation is better, so we shouldn't hesitate to edit below as
11975 @c needed. However if the change you want to make to this documentation
11976 @c can be done in an automated way, it's probably easier to change
11977 @c (generate-documentation) than to make it below and have to deal with
11978 @c the churn as dovecot updates.
11980 Available @code{dovecot-configuration} fields are:
11982 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11983 The dovecot package.
11986 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11987 A list of IPs or hosts where to listen for connections. @samp{*}
11988 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11989 interfaces. If you want to specify non-default ports or anything more
11990 complex, customize the address and port fields of the
11991 @samp{inet-listener} of the specific services you are interested in.
11994 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11995 List of protocols we want to serve. Available protocols include
11996 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11998 Available @code{protocol-configuration} fields are:
12000 @deftypevr {@code{protocol-configuration} parameter} string name
12001 The name of the protocol.
12004 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
12005 UNIX socket path to the master authentication server to find users.
12006 This is used by imap (for shared users) and lda.
12007 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12010 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
12011 Space separated list of plugins to load.
12014 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
12015 Maximum number of IMAP connections allowed for a user from each IP
12016 address. NOTE: The username is compared case-sensitively.
12017 Defaults to @samp{10}.
12022 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
12023 List of services to enable. Available services include @samp{imap},
12024 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
12027 Available @code{service-configuration} fields are:
12029 @deftypevr {@code{service-configuration} parameter} string kind
12030 The service kind. Valid values include @code{director},
12031 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
12032 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
12033 @code{tcpwrap}, @code{quota-warning}, or anything else.
12036 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
12037 Listeners for the service. A listener is either a
12038 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
12039 an @code{inet-listener-configuration}.
12040 Defaults to @samp{()}.
12042 Available @code{unix-listener-configuration} fields are:
12044 @deftypevr {@code{unix-listener-configuration} parameter} string path
12045 Path to the file, relative to @code{base-dir} field. This is also used as
12049 @deftypevr {@code{unix-listener-configuration} parameter} string mode
12050 The access mode for the socket.
12051 Defaults to @samp{"0600"}.
12054 @deftypevr {@code{unix-listener-configuration} parameter} string user
12055 The user to own the socket.
12056 Defaults to @samp{""}.
12059 @deftypevr {@code{unix-listener-configuration} parameter} string group
12060 The group to own the socket.
12061 Defaults to @samp{""}.
12065 Available @code{fifo-listener-configuration} fields are:
12067 @deftypevr {@code{fifo-listener-configuration} parameter} string path
12068 Path to the file, relative to @code{base-dir} field. This is also used as
12072 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
12073 The access mode for the socket.
12074 Defaults to @samp{"0600"}.
12077 @deftypevr {@code{fifo-listener-configuration} parameter} string user
12078 The user to own the socket.
12079 Defaults to @samp{""}.
12082 @deftypevr {@code{fifo-listener-configuration} parameter} string group
12083 The group to own the socket.
12084 Defaults to @samp{""}.
12088 Available @code{inet-listener-configuration} fields are:
12090 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
12091 The protocol to listen for.
12094 @deftypevr {@code{inet-listener-configuration} parameter} string address
12095 The address on which to listen, or empty for all addresses.
12096 Defaults to @samp{""}.
12099 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
12100 The port on which to listen.
12103 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
12104 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
12106 Defaults to @samp{#t}.
12111 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
12112 Number of connections to handle before starting a new process.
12113 Typically the only useful values are 0 (unlimited) or 1. 1 is more
12114 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
12115 Defaults to @samp{1}.
12118 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
12119 Number of processes to always keep waiting for more connections.
12120 Defaults to @samp{0}.
12123 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
12124 If you set @samp{service-count 0}, you probably need to grow
12126 Defaults to @samp{256000000}.
12131 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
12132 Dict configuration, as created by the @code{dict-configuration}
12135 Available @code{dict-configuration} fields are:
12137 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
12138 A list of key-value pairs that this dict should hold.
12139 Defaults to @samp{()}.
12144 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
12145 A list of passdb configurations, each one created by the
12146 @code{passdb-configuration} constructor.
12148 Available @code{passdb-configuration} fields are:
12150 @deftypevr {@code{passdb-configuration} parameter} string driver
12151 The driver that the passdb should use. Valid values include
12152 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
12154 Defaults to @samp{"pam"}.
12157 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
12158 Space separated list of arguments to the passdb driver.
12159 Defaults to @samp{""}.
12164 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
12165 List of userdb configurations, each one created by the
12166 @code{userdb-configuration} constructor.
12168 Available @code{userdb-configuration} fields are:
12170 @deftypevr {@code{userdb-configuration} parameter} string driver
12171 The driver that the userdb should use. Valid values include
12172 @samp{passwd} and @samp{static}.
12173 Defaults to @samp{"passwd"}.
12176 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
12177 Space separated list of arguments to the userdb driver.
12178 Defaults to @samp{""}.
12181 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
12182 Override fields from passwd.
12183 Defaults to @samp{()}.
12188 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
12189 Plug-in configuration, created by the @code{plugin-configuration}
12193 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
12194 List of namespaces. Each item in the list is created by the
12195 @code{namespace-configuration} constructor.
12197 Available @code{namespace-configuration} fields are:
12199 @deftypevr {@code{namespace-configuration} parameter} string name
12200 Name for this namespace.
12203 @deftypevr {@code{namespace-configuration} parameter} string type
12204 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
12205 Defaults to @samp{"private"}.
12208 @deftypevr {@code{namespace-configuration} parameter} string separator
12209 Hierarchy separator to use. You should use the same separator for
12210 all namespaces or some clients get confused. @samp{/} is usually a good
12211 one. The default however depends on the underlying mail storage
12213 Defaults to @samp{""}.
12216 @deftypevr {@code{namespace-configuration} parameter} string prefix
12217 Prefix required to access this namespace. This needs to be
12218 different for all namespaces. For example @samp{Public/}.
12219 Defaults to @samp{""}.
12222 @deftypevr {@code{namespace-configuration} parameter} string location
12223 Physical location of the mailbox. This is in the same format as
12224 mail_location, which is also the default for it.
12225 Defaults to @samp{""}.
12228 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
12229 There can be only one INBOX, and this setting defines which
12231 Defaults to @samp{#f}.
12234 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
12235 If namespace is hidden, it's not advertised to clients via NAMESPACE
12236 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
12237 useful when converting from another server with different namespaces
12238 which you want to deprecate but still keep working. For example you can
12239 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
12241 Defaults to @samp{#f}.
12244 @deftypevr {@code{namespace-configuration} parameter} boolean list?
12245 Show the mailboxes under this namespace with the LIST command. This
12246 makes the namespace visible for clients that do not support the NAMESPACE
12247 extension. The special @code{children} value lists child mailboxes, but
12248 hides the namespace prefix.
12249 Defaults to @samp{#t}.
12252 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
12253 Namespace handles its own subscriptions. If set to @code{#f}, the
12254 parent namespace handles them. The empty prefix should always have this
12256 Defaults to @samp{#t}.
12259 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
12260 List of predefined mailboxes in this namespace.
12261 Defaults to @samp{()}.
12263 Available @code{mailbox-configuration} fields are:
12265 @deftypevr {@code{mailbox-configuration} parameter} string name
12266 Name for this mailbox.
12269 @deftypevr {@code{mailbox-configuration} parameter} string auto
12270 @samp{create} will automatically create this mailbox.
12271 @samp{subscribe} will both create and subscribe to the mailbox.
12272 Defaults to @samp{"no"}.
12275 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
12276 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
12277 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
12278 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
12279 Defaults to @samp{()}.
12286 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
12287 Base directory where to store runtime data.
12288 Defaults to @samp{"/var/run/dovecot/"}.
12291 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
12292 Greeting message for clients.
12293 Defaults to @samp{"Dovecot ready."}.
12296 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
12297 List of trusted network ranges. Connections from these IPs are
12298 allowed to override their IP addresses and ports (for logging and for
12299 authentication checks). @samp{disable-plaintext-auth} is also ignored
12300 for these networks. Typically you would specify your IMAP proxy servers
12302 Defaults to @samp{()}.
12305 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
12306 List of login access check sockets (e.g. tcpwrap).
12307 Defaults to @samp{()}.
12310 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
12311 Show more verbose process titles (in ps). Currently shows user name
12312 and IP address. Useful for seeing who is actually using the IMAP
12313 processes (e.g. shared mailboxes or if the same uid is used for multiple
12315 Defaults to @samp{#f}.
12318 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
12319 Should all processes be killed when Dovecot master process shuts down.
12320 Setting this to @code{#f} means that Dovecot can be upgraded without
12321 forcing existing client connections to close (although that could also
12322 be a problem if the upgrade is e.g. due to a security fix).
12323 Defaults to @samp{#t}.
12326 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
12327 If non-zero, run mail commands via this many connections to doveadm
12328 server, instead of running them directly in the same process.
12329 Defaults to @samp{0}.
12332 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
12333 UNIX socket or host:port used for connecting to doveadm server.
12334 Defaults to @samp{"doveadm-server"}.
12337 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12338 List of environment variables that are preserved on Dovecot startup
12339 and passed down to all of its child processes. You can also give
12340 key=value pairs to always set specific settings.
12343 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12344 Disable LOGIN command and all other plaintext authentications unless
12345 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12346 matches the local IP (i.e. you're connecting from the same computer),
12347 the connection is considered secure and plaintext authentication is
12348 allowed. See also ssl=required setting.
12349 Defaults to @samp{#t}.
12352 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12353 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12354 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12355 for caching to be used.
12356 Defaults to @samp{0}.
12359 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12360 Time to live for cached data. After TTL expires the cached record
12361 is no longer used, *except* if the main database lookup returns internal
12362 failure. We also try to handle password changes automatically: If
12363 user's previous authentication was successful, but this one wasn't, the
12364 cache isn't used. For now this works only with plaintext
12366 Defaults to @samp{"1 hour"}.
12369 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12370 TTL for negative hits (user not found, password mismatch).
12371 0 disables caching them completely.
12372 Defaults to @samp{"1 hour"}.
12375 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12376 List of realms for SASL authentication mechanisms that need them.
12377 You can leave it empty if you don't want to support multiple realms.
12378 Many clients simply use the first one listed here, so keep the default
12380 Defaults to @samp{()}.
12383 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12384 Default realm/domain to use if none was specified. This is used for
12385 both SASL realms and appending @@domain to username in plaintext
12387 Defaults to @samp{""}.
12390 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12391 List of allowed characters in username. If the user-given username
12392 contains a character not listed in here, the login automatically fails.
12393 This is just an extra check to make sure user can't exploit any
12394 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12395 you want to allow all characters, set this value to empty.
12396 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12399 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12400 Username character translations before it's looked up from
12401 databases. The value contains series of from -> to characters. For
12402 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12403 translated to @samp{@@}.
12404 Defaults to @samp{""}.
12407 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12408 Username formatting before it's looked up from databases. You can
12409 use the standard variables here, e.g. %Lu would lowercase the username,
12410 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12411 change the @samp{@@} into @samp{-AT-}. This translation is done after
12412 @samp{auth-username-translation} changes.
12413 Defaults to @samp{"%Lu"}.
12416 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12417 If you want to allow master users to log in by specifying the master
12418 username within the normal username string (i.e. not using SASL
12419 mechanism's support for it), you can specify the separator character
12420 here. The format is then <username><separator><master username>.
12421 UW-IMAP uses @samp{*} as the separator, so that could be a good
12423 Defaults to @samp{""}.
12426 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12427 Username to use for users logging in with ANONYMOUS SASL
12429 Defaults to @samp{"anonymous"}.
12432 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12433 Maximum number of dovecot-auth worker processes. They're used to
12434 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12435 They're automatically created and destroyed as needed.
12436 Defaults to @samp{30}.
12439 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12440 Host name to use in GSSAPI principal names. The default is to use
12441 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12442 allow all keytab entries.
12443 Defaults to @samp{""}.
12446 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12447 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12448 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12449 need to change the auth service to run as root to be able to read this
12451 Defaults to @samp{""}.
12454 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12455 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12456 and @samp{ntlm-auth} helper.
12457 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12458 Defaults to @samp{#f}.
12461 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12462 Path for Samba's @samp{ntlm-auth} helper binary.
12463 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12466 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12467 Time to delay before replying to failed authentications.
12468 Defaults to @samp{"2 secs"}.
12471 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12472 Require a valid SSL client certificate or the authentication
12474 Defaults to @samp{#f}.
12477 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12478 Take the username from client's SSL certificate, using
12479 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12481 Defaults to @samp{#f}.
12484 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12485 List of wanted authentication mechanisms. Supported mechanisms are:
12486 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12487 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12488 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12489 @samp{disable-plaintext-auth} setting.
12492 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12493 List of IPs or hostnames to all director servers, including ourself.
12494 Ports can be specified as ip:port. The default port is the same as what
12495 director service's @samp{inet-listener} is using.
12496 Defaults to @samp{()}.
12499 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12500 List of IPs or hostnames to all backend mail servers. Ranges are
12501 allowed too, like 10.0.0.10-10.0.0.30.
12502 Defaults to @samp{()}.
12505 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12506 How long to redirect users to a specific server after it no longer
12507 has any connections.
12508 Defaults to @samp{"15 min"}.
12511 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12512 TCP/IP port that accepts doveadm connections (instead of director
12513 connections) If you enable this, you'll also need to add
12514 @samp{inet-listener} for the port.
12515 Defaults to @samp{0}.
12518 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12519 How the username is translated before being hashed. Useful values
12520 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12521 are shared within domain.
12522 Defaults to @samp{"%Lu"}.
12525 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12526 Log file to use for error messages. @samp{syslog} logs to syslog,
12527 @samp{/dev/stderr} logs to stderr.
12528 Defaults to @samp{"syslog"}.
12531 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12532 Log file to use for informational messages. Defaults to
12534 Defaults to @samp{""}.
12537 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12538 Log file to use for debug messages. Defaults to
12539 @samp{info-log-path}.
12540 Defaults to @samp{""}.
12543 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12544 Syslog facility to use if you're logging to syslog. Usually if you
12545 don't want to use @samp{mail}, you'll use local0..local7. Also other
12546 standard facilities are supported.
12547 Defaults to @samp{"mail"}.
12550 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12551 Log unsuccessful authentication attempts and the reasons why they
12553 Defaults to @samp{#f}.
12556 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12557 In case of password mismatches, log the attempted password. Valid
12558 values are no, plain and sha1. sha1 can be useful for detecting brute
12559 force password attempts vs. user simply trying the same password over
12560 and over again. You can also truncate the value to n chars by appending
12561 ":n" (e.g. sha1:6).
12562 Defaults to @samp{#f}.
12565 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12566 Even more verbose logging for debugging purposes. Shows for example
12568 Defaults to @samp{#f}.
12571 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12572 In case of password mismatches, log the passwords and used scheme so
12573 the problem can be debugged. Enabling this also enables
12575 Defaults to @samp{#f}.
12578 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12579 Enable mail process debugging. This can help you figure out why
12580 Dovecot isn't finding your mails.
12581 Defaults to @samp{#f}.
12584 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12585 Show protocol level SSL errors.
12586 Defaults to @samp{#f}.
12589 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12590 Prefix for each line written to log file. % codes are in
12591 strftime(3) format.
12592 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12595 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12596 List of elements we want to log. The elements which have a
12597 non-empty variable value are joined together to form a comma-separated
12601 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12602 Login log format. %s contains @samp{login-log-format-elements}
12603 string, %$ contains the data we want to log.
12604 Defaults to @samp{"%$: %s"}.
12607 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12608 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12609 of possible variables you can use.
12610 Defaults to @samp{"\"%s(%u): \""}.
12613 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12614 Format to use for logging mail deliveries. You can use variables:
12617 Delivery status message (e.g. @samp{saved to INBOX})
12629 Defaults to @samp{"msgid=%m: %$"}.
12632 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12633 Location for users' mailboxes. The default is empty, which means
12634 that Dovecot tries to find the mailboxes automatically. This won't work
12635 if the user doesn't yet have any mail, so you should explicitly tell
12636 Dovecot the full location.
12638 If you're using mbox, giving a path to the INBOX
12639 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12640 where the other mailboxes are kept. This is called the "root mail
12641 directory", and it must be the first path given in the
12642 @samp{mail-location} setting.
12644 There are a few special variables you can use, eg.:
12650 user part in user@@domain, same as %u if there's no domain
12652 domain part in user@@domain, empty if there's no domain
12657 See doc/wiki/Variables.txt for full list. Some examples:
12659 @item maildir:~/Maildir
12660 @item mbox:~/mail:INBOX=/var/mail/%u
12661 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12663 Defaults to @samp{""}.
12666 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12667 System user and group used to access mails. If you use multiple,
12668 userdb can override these by returning uid or gid fields. You can use
12669 either numbers or names. <doc/wiki/UserIds.txt>.
12670 Defaults to @samp{""}.
12673 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12675 Defaults to @samp{""}.
12678 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12679 Group to enable temporarily for privileged operations. Currently
12680 this is used only with INBOX when either its initial creation or
12681 dotlocking fails. Typically this is set to "mail" to give access to
12683 Defaults to @samp{""}.
12686 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12687 Grant access to these supplementary groups for mail processes.
12688 Typically these are used to set up access to shared mailboxes. Note
12689 that it may be dangerous to set these if users can create
12690 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12691 could allow a user to delete others' mailboxes, or ln -s
12692 /secret/shared/box ~/mail/mybox would allow reading it).
12693 Defaults to @samp{""}.
12696 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12697 Allow full file system access to clients. There's no access checks
12698 other than what the operating system does for the active UID/GID. It
12699 works with both maildir and mboxes, allowing you to prefix mailboxes
12700 names with e.g. /path/ or ~user/.
12701 Defaults to @samp{#f}.
12704 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12705 Don't use mmap() at all. This is required if you store indexes to
12706 shared file systems (NFS or clustered file system).
12707 Defaults to @samp{#f}.
12710 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12711 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12712 supports @samp{O_EXCL} since version 3, so this should be safe to use
12713 nowadays by default.
12714 Defaults to @samp{#t}.
12717 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12718 When to use fsync() or fdatasync() calls:
12721 Whenever necessary to avoid losing important data
12723 Useful with e.g. NFS when write()s are delayed
12725 Never use it (best performance, but crashes can lose data).
12727 Defaults to @samp{"optimized"}.
12730 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12731 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12732 NFS caches whenever needed. If you're using only a single mail server
12734 Defaults to @samp{#f}.
12737 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12738 Mail index files also exist in NFS. Setting this to yes requires
12739 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12740 Defaults to @samp{#f}.
12743 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12744 Locking method for index files. Alternatives are fcntl, flock and
12745 dotlock. Dotlocking uses some tricks which may create more disk I/O
12746 than other locking methods. NFS users: flock doesn't work, remember to
12747 change @samp{mmap-disable}.
12748 Defaults to @samp{"fcntl"}.
12751 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12752 Directory in which LDA/LMTP temporarily stores incoming mails >128
12754 Defaults to @samp{"/tmp"}.
12757 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12758 Valid UID range for users. This is mostly to make sure that users can't
12759 log in as daemons or other system users. Note that denying root logins is
12760 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12762 Defaults to @samp{500}.
12765 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12767 Defaults to @samp{0}.
12770 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12771 Valid GID range for users. Users having non-valid GID as primary group ID
12772 aren't allowed to log in. If user belongs to supplementary groups with
12773 non-valid GIDs, those groups are not set.
12774 Defaults to @samp{1}.
12777 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12779 Defaults to @samp{0}.
12782 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12783 Maximum allowed length for mail keyword name. It's only forced when
12784 trying to create new keywords.
12785 Defaults to @samp{50}.
12788 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12789 List of directories under which chrooting is allowed for mail
12790 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12791 too). This setting doesn't affect @samp{login-chroot}
12792 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12793 "/./" in home dirs are ignored. WARNING: Never add directories here
12794 which local users can modify, that may lead to root exploit. Usually
12795 this should be done only if you don't allow shell access for users.
12796 <doc/wiki/Chrooting.txt>.
12797 Defaults to @samp{()}.
12800 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12801 Default chroot directory for mail processes. This can be overridden
12802 for specific users in user database by giving /./ in user's home
12803 directory (e.g. /home/./user chroots into /home). Note that usually
12804 there is no real need to do chrooting, Dovecot doesn't allow users to
12805 access files outside their mail directory anyway. If your home
12806 directories are prefixed with the chroot directory, append "/." to
12807 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12808 Defaults to @samp{""}.
12811 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12812 UNIX socket path to master authentication server to find users.
12813 This is used by imap (for shared users) and lda.
12814 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12817 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12818 Directory where to look up mail plugins.
12819 Defaults to @samp{"/usr/lib/dovecot"}.
12822 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12823 List of plugins to load for all services. Plugins specific to IMAP,
12824 LDA, etc. are added to this list in their own .conf files.
12825 Defaults to @samp{()}.
12828 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12829 The minimum number of mails in a mailbox before updates are done to
12830 cache file. This allows optimizing Dovecot's behavior to do less disk
12831 writes at the cost of more disk reads.
12832 Defaults to @samp{0}.
12835 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12836 When IDLE command is running, mailbox is checked once in a while to
12837 see if there are any new mails or other changes. This setting defines
12838 the minimum time to wait between those checks. Dovecot can also use
12839 dnotify, inotify and kqueue to find out immediately when changes
12841 Defaults to @samp{"30 secs"}.
12844 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12845 Save mails with CR+LF instead of plain LF. This makes sending those
12846 mails take less CPU, especially with sendfile() syscall with Linux and
12847 FreeBSD. But it also creates a bit more disk I/O which may just make it
12848 slower. Also note that if other software reads the mboxes/maildirs,
12849 they may handle the extra CRs wrong and cause problems.
12850 Defaults to @samp{#f}.
12853 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12854 By default LIST command returns all entries in maildir beginning
12855 with a dot. Enabling this option makes Dovecot return only entries
12856 which are directories. This is done by stat()ing each entry, so it
12857 causes more disk I/O.
12858 (For systems setting struct @samp{dirent->d_type} this check is free
12859 and it's done always regardless of this setting).
12860 Defaults to @samp{#f}.
12863 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12864 When copying a message, do it with hard links whenever possible.
12865 This makes the performance much better, and it's unlikely to have any
12867 Defaults to @samp{#t}.
12870 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12871 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12872 directory only when its mtime changes unexpectedly or when we can't find
12873 the mail otherwise.
12874 Defaults to @samp{#f}.
12877 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12878 Which locking methods to use for locking mbox. There are four
12883 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12884 solution. If you want to use /var/mail/ like directory, the users will
12885 need write access to that directory.
12887 Same as dotlock, but if it fails because of permissions or because there
12888 isn't enough disk space, just skip it.
12890 Use this if possible. Works with NFS too if lockd is used.
12892 May not exist in all systems. Doesn't work with NFS.
12894 May not exist in all systems. Doesn't work with NFS.
12897 You can use multiple locking methods; if you do the order they're declared
12898 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12899 locking methods as well. Some operating systems don't allow using some of
12900 them simultaneously.
12903 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12907 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12908 Maximum time to wait for lock (all of them) before aborting.
12909 Defaults to @samp{"5 mins"}.
12912 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12913 If dotlock exists but the mailbox isn't modified in any way,
12914 override the lock file after this much time.
12915 Defaults to @samp{"2 mins"}.
12918 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12919 When mbox changes unexpectedly we have to fully read it to find out
12920 what changed. If the mbox is large this can take a long time. Since
12921 the change is usually just a newly appended mail, it'd be faster to
12922 simply read the new mails. If this setting is enabled, Dovecot does
12923 this but still safely fallbacks to re-reading the whole mbox file
12924 whenever something in mbox isn't how it's expected to be. The only real
12925 downside to this setting is that if some other MUA changes message
12926 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12927 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12928 Defaults to @samp{#t}.
12931 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12932 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12933 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12934 @samp{mbox-dirty-syncs} is ignored.
12935 Defaults to @samp{#f}.
12938 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12939 Delay writing mbox headers until doing a full write sync (EXPUNGE
12940 and CHECK commands and when closing the mailbox). This is especially
12941 useful for POP3 where clients often delete all mails. The downside is
12942 that our changes aren't immediately visible to other MUAs.
12943 Defaults to @samp{#t}.
12946 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12947 If mbox size is smaller than this (e.g. 100k), don't write index
12948 files. If an index file already exists it's still read, just not
12950 Defaults to @samp{0}.
12953 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12954 Maximum dbox file size until it's rotated.
12955 Defaults to @samp{2000000}.
12958 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12959 Maximum dbox file age until it's rotated. Typically in days. Day
12960 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12962 Defaults to @samp{"1d"}.
12965 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12966 When creating new mdbox files, immediately preallocate their size to
12967 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12968 with some file systems (ext4, xfs).
12969 Defaults to @samp{#f}.
12972 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12973 sdbox and mdbox support saving mail attachments to external files,
12974 which also allows single instance storage for them. Other backends
12975 don't support this for now.
12977 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12979 Directory root where to store mail attachments. Disabled, if empty.
12980 Defaults to @samp{""}.
12983 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12984 Attachments smaller than this aren't saved externally. It's also
12985 possible to write a plugin to disable saving specific attachments
12987 Defaults to @samp{128000}.
12990 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12991 File system backend to use for saving attachments:
12994 No SiS done by Dovecot (but this might help FS's own deduplication)
12996 SiS with immediate byte-by-byte comparison during saving
12997 @item sis-queue posix
12998 SiS with delayed comparison and deduplication.
13000 Defaults to @samp{"sis posix"}.
13003 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
13004 Hash format to use in attachment filenames. You can add any text and
13005 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
13006 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
13007 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
13008 Defaults to @samp{"%@{sha1@}"}.
13011 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
13013 Defaults to @samp{100}.
13016 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
13018 Defaults to @samp{1000}.
13021 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
13022 Default VSZ (virtual memory size) limit for service processes.
13023 This is mainly intended to catch and kill processes that leak memory
13024 before they eat up everything.
13025 Defaults to @samp{256000000}.
13028 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
13029 Login user is internally used by login processes. This is the most
13030 untrusted user in Dovecot system. It shouldn't have access to anything
13032 Defaults to @samp{"dovenull"}.
13035 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
13036 Internal user is used by unprivileged processes. It should be
13037 separate from login user, so that login processes can't disturb other
13039 Defaults to @samp{"dovecot"}.
13042 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
13043 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
13044 Defaults to @samp{"required"}.
13047 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
13048 PEM encoded X.509 SSL/TLS certificate (public key).
13049 Defaults to @samp{"</etc/dovecot/default.pem"}.
13052 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
13053 PEM encoded SSL/TLS private key. The key is opened before
13054 dropping root privileges, so keep the key file unreadable by anyone but
13056 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
13059 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
13060 If key file is password protected, give the password here.
13061 Alternatively give it when starting dovecot with -p parameter. Since
13062 this file is often world-readable, you may want to place this setting
13063 instead to a different.
13064 Defaults to @samp{""}.
13067 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
13068 PEM encoded trusted certificate authority. Set this only if you
13069 intend to use @samp{ssl-verify-client-cert? #t}. The file should
13070 contain the CA certificate(s) followed by the matching
13071 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
13072 Defaults to @samp{""}.
13075 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
13076 Require that CRL check succeeds for client certificates.
13077 Defaults to @samp{#t}.
13080 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
13081 Request client to send a certificate. If you also want to require
13082 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
13083 Defaults to @samp{#f}.
13086 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
13087 Which field from certificate to use for username. commonName and
13088 x500UniqueIdentifier are the usual choices. You'll also need to set
13089 @samp{auth-ssl-username-from-cert? #t}.
13090 Defaults to @samp{"commonName"}.
13093 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
13094 How often to regenerate the SSL parameters file. Generation is
13095 quite CPU intensive operation. The value is in hours, 0 disables
13096 regeneration entirely.
13097 Defaults to @samp{168}.
13100 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
13101 SSL protocols to use.
13102 Defaults to @samp{"!SSLv2"}.
13105 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
13106 SSL ciphers to use.
13107 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
13110 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
13111 SSL crypto device to use, for valid values run "openssl engine".
13112 Defaults to @samp{""}.
13115 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
13116 Address to use when sending rejection mails.
13117 %d expands to recipient domain.
13118 Defaults to @samp{"postmaster@@%d"}.
13121 @deftypevr {@code{dovecot-configuration} parameter} string hostname
13122 Hostname to use in various parts of sent mails (e.g. in Message-Id)
13123 and in LMTP replies. Default is the system's real hostname@@domain.
13124 Defaults to @samp{""}.
13127 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
13128 If user is over quota, return with temporary failure instead of
13130 Defaults to @samp{#f}.
13133 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
13134 Binary to use for sending mails.
13135 Defaults to @samp{"/usr/sbin/sendmail"}.
13138 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
13139 If non-empty, send mails via this SMTP host[:port] instead of
13141 Defaults to @samp{""}.
13144 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
13145 Subject: header to use for rejection mails. You can use the same
13146 variables as for @samp{rejection-reason} below.
13147 Defaults to @samp{"Rejected: %s"}.
13150 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
13151 Human readable error message for rejection mails. You can use
13164 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
13167 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
13168 Delimiter character between local-part and detail in email
13170 Defaults to @samp{"+"}.
13173 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
13174 Header where the original recipient address (SMTP's RCPT TO:
13175 address) is taken from if not available elsewhere. With dovecot-lda -a
13176 parameter overrides this. A commonly used header for this is
13178 Defaults to @samp{""}.
13181 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
13182 Should saving a mail to a nonexistent mailbox automatically create
13184 Defaults to @samp{#f}.
13187 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
13188 Should automatically created mailboxes be also automatically
13190 Defaults to @samp{#f}.
13193 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
13194 Maximum IMAP command line length. Some clients generate very long
13195 command lines with huge mailboxes, so you may need to raise this if you
13196 get "Too long argument" or "IMAP command line too large" errors
13198 Defaults to @samp{64000}.
13201 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
13202 IMAP logout format string:
13205 total number of bytes read from client
13207 total number of bytes sent to client.
13209 Defaults to @samp{"in=%i out=%o"}.
13212 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
13213 Override the IMAP CAPABILITY response. If the value begins with '+',
13214 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
13215 Defaults to @samp{""}.
13218 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
13219 How long to wait between "OK Still here" notifications when client
13221 Defaults to @samp{"2 mins"}.
13224 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
13225 ID field names and values to send to clients. Using * as the value
13226 makes Dovecot use the default value. The following fields have default
13227 values currently: name, version, os, os-version, support-url,
13229 Defaults to @samp{""}.
13232 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
13233 ID fields sent by client to log. * means everything.
13234 Defaults to @samp{""}.
13237 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
13238 Workarounds for various client bugs:
13241 @item delay-newmail
13242 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
13243 CHECK commands. Some clients ignore them otherwise, for example OSX
13244 Mail (<v2.1). Outlook Express breaks more badly though, without this it
13245 may show user "Message no longer in server" errors. Note that OE6
13246 still breaks even with this workaround if synchronization is set to
13249 @item tb-extra-mailbox-sep
13250 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
13251 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
13252 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
13254 @item tb-lsub-flags
13255 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
13256 This makes Thunderbird realize they aren't selectable and show them
13257 greyed out, instead of only later giving "not selectable" popup error.
13259 Defaults to @samp{()}.
13262 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
13263 Host allowed in URLAUTH URLs sent by client. "*" allows all.
13264 Defaults to @samp{""}.
13268 Whew! Lots of configuration options. The nice thing about it though is
13269 that GuixSD has a complete interface to Dovecot's configuration
13270 language. This allows not only a nice way to declare configurations,
13271 but also offers reflective capabilities as well: users can write code to
13272 inspect and transform configurations from within Scheme.
13274 However, it could be that you just want to get a @code{dovecot.conf} up
13275 and running. In that case, you can pass an
13276 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
13277 @code{dovecot-service}. As its name indicates, an opaque configuration
13278 does not have easy reflective capabilities.
13280 Available @code{opaque-dovecot-configuration} fields are:
13282 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
13283 The dovecot package.
13286 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
13287 The contents of the @code{dovecot.conf}, as a string.
13290 For example, if your @code{dovecot.conf} is just the empty string, you
13291 could instantiate a dovecot service like this:
13294 (dovecot-service #:config
13295 (opaque-dovecot-configuration
13299 @subsubheading OpenSMTPD Service
13301 @deffn {Scheme Variable} opensmtpd-service-type
13302 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
13303 service, whose value should be an @code{opensmtpd-configuration} object
13304 as in this example:
13307 (service opensmtpd-service-type
13308 (opensmtpd-configuration
13309 (config-file (local-file "./my-smtpd.conf"))))
13313 @deftp {Data Type} opensmtpd-configuration
13314 Data type representing the configuration of opensmtpd.
13317 @item @code{package} (default: @var{opensmtpd})
13318 Package object of the OpenSMTPD SMTP server.
13320 @item @code{config-file} (default: @var{%default-opensmtpd-file})
13321 File-like object of the OpenSMTPD configuration file to use. By default
13322 it listens on the loopback network interface, and allows for mail from
13323 users and daemons on the local machine, as well as permitting email to
13324 remote servers. Run @command{man smtpd.conf} for more information.
13329 @subsubheading Exim Service
13331 @cindex mail transfer agent (MTA)
13332 @cindex MTA (mail transfer agent)
13335 @deffn {Scheme Variable} exim-service-type
13336 This is the type of the @uref{https://exim.org, Exim} mail transfer
13337 agent (MTA), whose value should be an @code{exim-configuration} object
13338 as in this example:
13341 (service exim-service-type
13342 (exim-configuration
13343 (config-file (local-file "./my-exim.conf"))))
13347 In order to use an @code{exim-service-type} service you must also have a
13348 @code{mail-aliases-service-type} service present in your
13349 @code{operating-system} (even if it has no aliases).
13351 @deftp {Data Type} exim-configuration
13352 Data type representing the configuration of exim.
13355 @item @code{package} (default: @var{exim})
13356 Package object of the Exim server.
13358 @item @code{config-file} (default: @code{#f})
13359 File-like object of the Exim configuration file to use. If its value is
13360 @code{#f} then use the default configuration file from the package
13361 provided in @code{package}. The resulting configuration file is loaded
13362 after setting the @code{exim_user} and @code{exim_group} configuration
13368 @subsubheading Mail Aliases Service
13370 @cindex email aliases
13371 @cindex aliases, for email addresses
13373 @deffn {Scheme Variable} mail-aliases-service-type
13374 This is the type of the service which provides @code{/etc/aliases},
13375 specifying how to deliver mail to users on this system.
13378 (service mail-aliases-service-type
13379 '(("postmaster" "bob")
13380 ("bob" "bob@@example.com" "bob@@example2.com")))
13384 The configuration for a @code{mail-aliases-service-type} service is an
13385 association list denoting how to deliver mail that comes to this
13386 system. Each entry is of the form @code{(alias addresses ...)}, with
13387 @code{alias} specifying the local alias and @code{addresses} specifying
13388 where to deliver this user's mail.
13390 The aliases aren't required to exist as users on the local system. In
13391 the above example, there doesn't need to be a @code{postmaster} entry in
13392 the @code{operating-system}'s @code{user-accounts} in order to deliver
13393 the @code{postmaster} mail to @code{bob} (which subsequently would
13394 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13396 @node Messaging Services
13397 @subsubsection Messaging Services
13402 The @code{(gnu services messaging)} module provides Guix service
13403 definitions for messaging services: currently only Prosody is supported.
13405 @subsubheading Prosody Service
13407 @deffn {Scheme Variable} prosody-service-type
13408 This is the type for the @uref{http://prosody.im, Prosody XMPP
13409 communication server}. Its value must be a @code{prosody-configuration}
13410 record as in this example:
13413 (service prosody-service-type
13414 (prosody-configuration
13415 (modules-enabled (cons "groups" %default-modules-enabled))
13418 (int-component-configuration
13419 (hostname "conference.example.net")
13421 (mod-muc (mod-muc-configuration)))))
13424 (virtualhost-configuration
13425 (domain "example.net"))))))
13428 See below for details about @code{prosody-configuration}.
13432 By default, Prosody does not need much configuration. Only one
13433 @code{virtualhosts} field is needed: it specifies the domain you wish
13436 Prosodyctl will help you generate X.509 certificates and keys:
13439 prosodyctl cert request example.net
13442 The available configuration parameters follow. Each parameter
13443 definition is preceded by its type; for example, @samp{string-list foo}
13444 indicates that the @code{foo} parameter should be specified as a list of
13445 strings. Types starting with @code{maybe-} denote parameters that won't
13446 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13448 There is also a way to specify the configuration as a string, if you
13449 have an old @code{prosody.cfg.lua} file that you want to port over from
13450 some other system; see the end for more details.
13452 @c The following documentation was initially generated by
13453 @c (generate-documentation) in (gnu services messaging). Manually maintained
13454 @c documentation is better, so we shouldn't hesitate to edit below as
13455 @c needed. However if the change you want to make to this documentation
13456 @c can be done in an automated way, it's probably easier to change
13457 @c (generate-documentation) than to make it below and have to deal with
13458 @c the churn as Prosody updates.
13460 Available @code{prosody-configuration} fields are:
13462 @deftypevr {@code{prosody-configuration} parameter} package prosody
13463 The Prosody package.
13466 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13467 Location of the Prosody data storage directory. See
13468 @url{http://prosody.im/doc/configure}.
13469 Defaults to @samp{"/var/lib/prosody"}.
13472 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13473 Additional plugin directories. They are searched in all the specified
13474 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13475 Defaults to @samp{()}.
13478 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13479 This is a list of accounts that are admins for the server. Note that you
13480 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13481 @url{http://prosody.im/doc/creating_accounts}.
13482 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13483 Defaults to @samp{()}.
13486 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13487 Enable use of libevent for better performance under high load. See
13488 @url{http://prosody.im/doc/libevent}.
13489 Defaults to @samp{#f}.
13492 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13493 This is the list of modules Prosody will load on startup. It looks for
13494 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13495 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13496 Defaults to @samp{%default-modules-enabled}.
13499 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13500 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13501 should you want to disable them then add them to this list.
13502 Defaults to @samp{()}.
13505 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13506 Path to a text file where the shared groups are defined. If this path is
13507 empty then @samp{mod_groups} does nothing. See
13508 @url{http://prosody.im/doc/modules/mod_groups}.
13509 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13512 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13513 Disable account creation by default, for security. See
13514 @url{http://prosody.im/doc/creating_accounts}.
13515 Defaults to @samp{#f}.
13518 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13519 These are the SSL/TLS-related settings. Most of them are disabled so to
13520 use Prosody's defaults. If you do not completely understand these options, do
13521 not add them to your config, it is easy to lower the security of your server
13522 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13524 Available @code{ssl-configuration} fields are:
13526 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13527 This determines what handshake to use.
13530 @deftypevr {@code{ssl-configuration} parameter} file-name key
13531 Path to your private key file, relative to @code{/etc/prosody}.
13532 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13535 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13536 Path to your certificate file, relative to @code{/etc/prosody}.
13537 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13540 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13541 Path to directory containing root certificates that you wish Prosody to
13542 trust when verifying the certificates of remote servers.
13543 Defaults to @samp{"/etc/ssl/certs"}.
13546 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13547 Path to a file containing root certificates that you wish Prosody to trust.
13548 Similar to @code{capath} but with all certificates concatenated together.
13551 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13552 A list of verification options (these mostly map to OpenSSL's
13553 @code{set_verify()} flags).
13556 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13557 A list of general options relating to SSL/TLS. These map to OpenSSL's
13558 @code{set_options()}. For a full list of options available in LuaSec, see the
13562 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13563 How long a chain of certificate authorities to check when looking for a
13564 trusted root certificate.
13567 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13568 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13569 clients, and in what order.
13572 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13573 A path to a file containing parameters for Diffie-Hellman key exchange. You
13574 can create such a file with:
13575 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13578 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13579 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13580 @samp{"secp384r1"}.
13583 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13584 A list of "extra" verification options.
13587 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13588 Password for encrypted private keys.
13593 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13594 Whether to force all client-to-server connections to be encrypted or not.
13595 See @url{http://prosody.im/doc/modules/mod_tls}.
13596 Defaults to @samp{#f}.
13599 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13600 Whether to force all server-to-server connections to be encrypted or not.
13601 See @url{http://prosody.im/doc/modules/mod_tls}.
13602 Defaults to @samp{#f}.
13605 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13606 Whether to require encryption and certificate authentication. This
13607 provides ideal security, but requires servers you communicate with to support
13608 encryption AND present valid, trusted certificates. See
13609 @url{http://prosody.im/doc/s2s#security}.
13610 Defaults to @samp{#f}.
13613 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13614 Many servers don't support encryption or have invalid or self-signed
13615 certificates. You can list domains here that will not be required to
13616 authenticate using certificates. They will be authenticated using DNS. See
13617 @url{http://prosody.im/doc/s2s#security}.
13618 Defaults to @samp{()}.
13621 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13622 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13623 valid certificates for some domains by specifying a list here. See
13624 @url{http://prosody.im/doc/s2s#security}.
13625 Defaults to @samp{()}.
13628 @deftypevr {@code{prosody-configuration} parameter} string authentication
13629 Select the authentication backend to use. The default provider stores
13630 passwords in plaintext and uses Prosody's configured data storage to store the
13631 authentication data. If you do not trust your server please see
13632 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13633 about using the hashed backend. See also
13634 @url{http://prosody.im/doc/authentication}
13635 Defaults to @samp{"internal_plain"}.
13638 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13639 Set logging options. Advanced logging configuration is not yet supported
13640 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13641 Defaults to @samp{"*syslog"}.
13644 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13645 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13646 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13649 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13650 A host in Prosody is a domain on which user accounts can be created. For
13651 example if you want your users to have addresses like
13652 @samp{"john.smith@@example.com"} then you need to add a host
13653 @samp{"example.com"}. All options in this list will apply only to this host.
13655 Note: the name "virtual" host is used in configuration to avoid confusion with
13656 the actual physical host that Prosody is installed on. A single Prosody
13657 instance can serve many domains, each one defined as a VirtualHost entry in
13658 Prosody's configuration. Conversely a server that hosts a single domain would
13659 have just one VirtualHost entry.
13661 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13663 Available @code{virtualhost-configuration} fields are:
13665 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13666 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13667 Domain you wish Prosody to serve.
13672 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13673 Components are extra services on a server which are available to clients,
13674 usually on a subdomain of the main server (such as
13675 @samp{"mycomponent.example.com"}). Example components might be chatroom
13676 servers, user directories, or gateways to other protocols.
13678 Internal components are implemented with Prosody-specific plugins. To add an
13679 internal component, you simply fill the hostname field, and the plugin you wish
13680 to use for the component.
13682 See @url{http://prosody.im/doc/components}.
13683 Defaults to @samp{()}.
13685 Available @code{int-component-configuration} fields are:
13687 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13688 @deftypevr {@code{int-component-configuration} parameter} string hostname
13689 Hostname of the component.
13692 @deftypevr {@code{int-component-configuration} parameter} string plugin
13693 Plugin you wish to use for the component.
13696 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13697 Multi-user chat (MUC) is Prosody's module for allowing you to create
13698 hosted chatrooms/conferences for XMPP users.
13700 General information on setting up and using multi-user chatrooms can be found
13701 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13702 which you should read if you are new to XMPP chatrooms.
13704 See also @url{http://prosody.im/doc/modules/mod_muc}.
13706 Available @code{mod-muc-configuration} fields are:
13708 @deftypevr {@code{mod-muc-configuration} parameter} string name
13709 The name to return in service discovery responses.
13710 Defaults to @samp{"Prosody Chatrooms"}.
13713 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13714 If @samp{#t}, this will only allow admins to create new chatrooms.
13715 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13716 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13717 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13718 restricts to service administrators only.
13719 Defaults to @samp{#f}.
13722 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13723 Maximum number of history messages that will be sent to the member that has
13724 just joined the room.
13725 Defaults to @samp{20}.
13732 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13733 External components use XEP-0114, which most standalone components
13734 support. To add an external component, you simply fill the hostname field. See
13735 @url{http://prosody.im/doc/components}.
13736 Defaults to @samp{()}.
13738 Available @code{ext-component-configuration} fields are:
13740 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13741 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13742 Password which the component will use to log in.
13745 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13746 Hostname of the component.
13751 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13752 Port(s) Prosody listens on for component connections.
13755 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13756 Interface Prosody listens on for component connections.
13757 Defaults to @samp{"127.0.0.1"}.
13760 It could be that you just want to get a @code{prosody.cfg.lua}
13761 up and running. In that case, you can pass an
13762 @code{opaque-prosody-configuration} record as the value of
13763 @code{prosody-service-type}. As its name indicates, an opaque configuration
13764 does not have easy reflective capabilities.
13765 Available @code{opaque-prosody-configuration} fields are:
13767 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13768 The prosody package.
13771 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13772 The contents of the @code{prosody.cfg.lua} to use.
13775 For example, if your @code{prosody.cfg.lua} is just the empty
13776 string, you could instantiate a prosody service like this:
13779 (service prosody-service-type
13780 (opaque-prosody-configuration
13781 (prosody.cfg.lua "")))
13784 @node Monitoring Services
13785 @subsubsection Monitoring Services
13787 @subsubheading Tailon Service
13789 @uref{https://tailon.readthedocs.io/, Tailon} is a web application for
13790 viewing and searching log files.
13792 The following example will configure the service with default values.
13793 By default, Tailon can be accessed on port 8080 (@code{http://localhost:8080}).
13796 (service tailon-service-type)
13799 The following example customises more of the Tailon configuration,
13800 adding @command{sed} to the list of allowed commands.
13803 (service tailon-service-type
13804 (tailon-configuration
13806 (tailon-configuration-file
13807 (allowed-commands '("tail" "grep" "awk" "sed"))))))
13811 @deftp {Data Type} tailon-configuration
13812 Data type representing the configuration of Tailon.
13813 This type has the following parameters:
13816 @item @code{config-file} (default: @code{(tailon-configuration-file)})
13817 The configuration file to use for Tailon. This can be set to a
13818 @dfn{tailon-configuration-file} record value, or any gexp
13819 (@pxref{G-Expressions}).
13821 For example, to instead use a local file, the @code{local-file} function
13825 (service tailon-service-type
13826 (tailon-configuration
13827 (config-file (local-file "./my-tailon.conf"))))
13830 @item @code{package} (default: @code{tailon})
13831 The tailon package to use.
13836 @deftp {Data Type} tailon-configuration-file
13837 Data type representing the configuration options for Tailon.
13838 This type has the following parameters:
13841 @item @code{files} (default: @code{(list "/var/log")})
13842 List of files to display. The list can include strings for a single file
13843 or directory, or a list, where the first item is the name of a
13844 subsection, and the remaining items are the files or directories in that
13847 @item @code{bind} (default: @code{"localhost:8080"})
13848 Address and port to which Tailon should bind on.
13850 @item @code{relative-root} (default: @code{#f})
13851 URL path to use for Tailon, set to @code{#f} to not use a path.
13853 @item @code{allow-transfers?} (default: @code{#t})
13854 Allow downloading the log files in the web interface.
13856 @item @code{follow-names?} (default: @code{#t})
13857 Allow tailing of not-yet existent files.
13859 @item @code{tail-lines} (default: @code{200})
13860 Number of lines to read initially from each file.
13862 @item @code{allowed-commands} (default: @code{(list "tail" "grep" "awk")})
13863 Commands to allow running. By default, @code{sed} is disabled.
13865 @item @code{debug?} (default: @code{#f})
13866 Set @code{debug?} to @code{#t} to show debug messages.
13868 @item @code{wrap-lines} (default: @code{#t})
13869 Initial line wrapping state in the web interface. Set to @code{#t} to
13870 initially wrap lines (the default), or to @code{#f} to initially not
13873 @item @code{http-auth} (default: @code{#f})
13874 HTTP authentication type to use. Set to @code{#f} to disable
13875 authentication (the default). Supported values are @code{"digest"} or
13878 @item @code{users} (default: @code{#f})
13879 If HTTP authentication is enabled (see @code{http-auth}), access will be
13880 restricted to the credentials provided here. To configure users, use a
13881 list of pairs, where the first element of the pair is the username, and
13882 the 2nd element of the pair is the password.
13885 (tailon-configuration-file
13886 (http-auth "basic")
13887 (users '(("user1" . "password1")
13888 ("user2" . "password2"))))
13895 @node Kerberos Services
13896 @subsubsection Kerberos Services
13899 The @code{(gnu services kerberos)} module provides services relating to
13900 the authentication protocol @dfn{Kerberos}.
13902 @subsubheading Krb5 Service
13904 Programs using a Kerberos client library normally
13905 expect a configuration file in @file{/etc/krb5.conf}.
13906 This service generates such a file from a definition provided in the
13907 operating system declaration.
13908 It does not cause any daemon to be started.
13910 No ``keytab'' files are provided by this service---you must explicitly create them.
13911 This service is known to work with the MIT client library, @code{mit-krb5}.
13912 Other implementations have not been tested.
13914 @defvr {Scheme Variable} krb5-service-type
13915 A service type for Kerberos 5 clients.
13919 Here is an example of its use:
13921 (service krb5-service-type
13922 (krb5-configuration
13923 (default-realm "EXAMPLE.COM")
13924 (allow-weak-crypto? #t)
13927 (name "EXAMPLE.COM")
13928 (admin-server "groucho.example.com")
13929 (kdc "karl.example.com"))
13932 (admin-server "kerb-admin.argrx.edu")
13933 (kdc "keys.argrx.edu"))))))
13937 This example provides a Kerberos@tie{}5 client configuration which:
13939 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13940 of which have distinct administration servers and key distribution centers;
13941 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13942 specified by clients;
13943 @item Accepts services which only support encryption types known to be weak.
13946 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13947 Only the most commonly used ones are described here.
13948 For a full list, and more detailed explanation of each, see the MIT
13949 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13953 @deftp {Data Type} krb5-realm
13954 @cindex realm, kerberos
13957 This field is a string identifying the name of the realm.
13958 A common convention is to use the fully qualified DNS name of your organization,
13959 converted to upper case.
13961 @item @code{admin-server}
13962 This field is a string identifying the host where the administration server is
13966 This field is a string identifying the key distribution center
13971 @deftp {Data Type} krb5-configuration
13974 @item @code{allow-weak-crypto?} (default: @code{#f})
13975 If this flag is @code{#t} then services which only offer encryption algorithms
13976 known to be weak will be accepted.
13978 @item @code{default-realm} (default: @code{#f})
13979 This field should be a string identifying the default Kerberos
13980 realm for the client.
13981 You should set this field to the name of your Kerberos realm.
13982 If this value is @code{#f}
13983 then a realm must be specified with every Kerberos principal when invoking programs
13984 such as @command{kinit}.
13986 @item @code{realms}
13987 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13989 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13995 @subsubheading PAM krb5 Service
13998 The @code{pam-krb5} service allows for login authentication and password
13999 management via Kerberos.
14000 You will need this service if you want PAM enabled applications to authenticate
14001 users using Kerberos.
14003 @defvr {Scheme Variable} pam-krb5-service-type
14004 A service type for the Kerberos 5 PAM module.
14007 @deftp {Data Type} pam-krb5-configuration
14008 Data type representing the configuration of the Kerberos 5 PAM module
14009 This type has the following parameters:
14011 @item @code{pam-krb5} (default: @code{pam-krb5})
14012 The pam-krb5 package to use.
14014 @item @code{minimum-uid} (default: @code{1000})
14015 The smallest user ID for which Kerberos authentications should be attempted.
14016 Local accounts with lower values will silently fail to authenticate.
14022 @subsubsection Web Services
14027 The @code{(gnu services web)} module provides the nginx web server and
14028 also a fastcgi wrapper daemon.
14030 @deffn {Scheme Variable} nginx-service-type
14031 Service type for the @uref{https://nginx.org/,NGinx} web server. The
14032 value for this service type is a @code{<nginx-configuration>} record.
14034 A simple example configuration is given below.
14037 (service nginx-service-type
14038 (nginx-configuration
14040 (list (nginx-server-configuration
14041 (server-name '("www.example.com"))
14042 (root "/srv/http/www.example.com")
14044 (ssl-certificate #f)
14045 (ssl-certificate-key #f))))))
14048 In addition to adding server blocks to the service configuration
14049 directly, this service can be extended by other services to add server
14050 blocks, as in this example:
14053 (simple-service 'my-extra-server nginx-service-type
14054 (list (nginx-server-configuration
14056 (ssl-certificate #f)
14057 (ssl-certificate-key #f)
14058 (root "/srv/http/extra-website"))))
14062 At startup, @command{nginx} has not yet read its configuration file, so
14063 it uses a default file to log error messages. If it fails to load its
14064 configuration file, that is where error messages are logged. After the
14065 configuration file is loaded, the default error log file changes as per
14066 configuration. In our case, startup error messages can be found in
14067 @file{/var/run/nginx/logs/error.log}, and after configuration in
14068 @file{/var/log/nginx/error.log}. The second location can be changed
14069 with the @var{log-directory} configuration option.
14071 @deffn {Data Type} nginx-configuration
14072 This data type represents the configuration for NGinx. Some
14073 configuration can be done through this and the other provided record
14074 types, or alternatively, a config file can be provided.
14077 @item @code{nginx} (default: @code{nginx})
14078 The nginx package to use.
14080 @item @code{log-directory} (default: @code{"/var/log/nginx"})
14081 The directory to which NGinx will write log files.
14083 @item @code{run-directory} (default: @code{"/var/run/nginx"})
14084 The directory in which NGinx will create a pid file, and write temporary
14087 @item @code{server-list} (default: @code{'()})
14088 A list of @dfn{server blocks} to create in the generated configuration
14089 file, the elements should be of type
14090 @code{<nginx-server-configuration>}.
14092 The following example would setup NGinx to serve @code{www.example.com}
14093 from the @code{/srv/http/www.example.com} directory, without using
14096 (service nginx-service-type
14097 (nginx-configuration
14099 (list (nginx-server-configuration
14100 (server-name '("www.example.com"))
14101 (root "/srv/http/www.example.com")
14103 (ssl-certificate #f)
14104 (ssl-certificate-key #f))))))
14107 @item @code{upstream-list} (default: @code{'()})
14108 A list of @dfn{upstream blocks} to create in the generated configuration
14109 file, the elements should be of type
14110 @code{<nginx-upstream-configuration>}.
14112 Configuring upstreams through the @code{upstream-list} can be useful
14113 when combined with @code{locations} in the
14114 @code{<nginx-server-configuration>} records. The following example
14115 creates a server configuration with one location configuration, that
14116 will proxy requests to a upstream configuration, which will handle
14117 requests with two servers.
14122 (nginx-configuration
14124 (list (nginx-server-configuration
14125 (server-name '("www.example.com"))
14126 (root "/srv/http/www.example.com")
14128 (ssl-certificate #f)
14129 (ssl-certificate-key #f)
14132 (nginx-location-configuration
14134 (body '("proxy_pass http://server-proxy;"))))))))
14136 (list (nginx-upstream-configuration
14137 (name "server-proxy")
14138 (servers (list "server1.example.com"
14139 "server2.example.com")))))))
14142 @item @code{config-file} (default: @code{#f})
14143 If the @var{config-file} is provided, this will be used, rather than
14144 generating a configuration file from the provided @code{log-directory},
14145 @code{run-directory}, @code{server-list} and @code{upstream-list}. For
14146 proper operation, these arguments should match what is in
14147 @var{config-file} to ensure that the directories are created when the
14148 service is activated.
14150 This can be useful if you have an existing configuration file, or it's
14151 not possible to do what is required through the other parts of the
14152 nginx-configuration record.
14157 @deftp {Data Type} nginx-server-configuration
14158 Data type representing the configuration of an nginx server block.
14159 This type has the following parameters:
14162 @item @code{http-port} (default: @code{80})
14163 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
14164 nginx should not listen for HTTP (non secure) connection for this
14165 @dfn{server block}.
14167 @item @code{https-port} (default: @code{443})
14168 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
14169 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
14171 Note that nginx can listen for HTTP and HTTPS connections in the same
14172 @dfn{server block}.
14174 @item @code{server-name} (default: @code{(list 'default)})
14175 A list of server names this server represents. @code{'default} represents the
14176 default server for connections matching no other server.
14178 @item @code{root} (default: @code{"/srv/http"})
14179 Root of the website nginx will serve.
14181 @item @code{locations} (default: @code{'()})
14182 A list of @dfn{nginx-location-configuration} or
14183 @dfn{nginx-named-location-configuration} records to use within this
14186 @item @code{index} (default: @code{(list "index.html")})
14187 Index files to look for when clients ask for a directory. If it cannot be found,
14188 Nginx will send the list of files in the directory.
14190 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
14191 Where to find the certificate for secure connections. Set it to @code{#f} if
14192 you don't have a certificate or you don't want to use HTTPS.
14194 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
14195 Where to find the private key for secure connections. Set it to @code{#f} if
14196 you don't have a key or you don't want to use HTTPS.
14198 @item @code{server-tokens?} (default: @code{#f})
14199 Whether the server should add its configuration to response.
14204 @deftp {Data Type} nginx-upstream-configuration
14205 Data type representing the configuration of an nginx @code{upstream}
14206 block. This type has the following parameters:
14210 Name for this group of servers.
14212 @item @code{servers}
14213 Specify the addresses of the servers in the group. The address can be
14214 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
14215 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
14216 prefix @samp{unix:}. For addresses using an IP address or domain name,
14217 the default port is 80, and a different port can be specified
14223 @deftp {Data Type} nginx-location-configuration
14224 Data type representing the configuration of an nginx @code{location}
14225 block. This type has the following parameters:
14229 URI which this location block matches.
14231 @anchor{nginx-location-configuration body}
14233 Body of the location block, specified as a string. This can contain many
14234 configuration directives. For example, to pass requests to a upstream
14235 server group defined using an @code{nginx-upstream-configuration} block,
14236 the following directive would be specified in the body @samp{proxy_pass
14237 http://upstream-name;}.
14242 @deftp {Data Type} nginx-named-location-configuration
14243 Data type representing the configuration of an nginx named location
14244 block. Named location blocks are used for request redirection, and not
14245 used for regular request processing. This type has the following
14250 Name to identify this location block.
14253 @xref{nginx-location-configuration body}, as the body for named location
14254 blocks can be used in a similar way to the
14255 @code{nginx-location-configuration body}. One restriction is that the
14256 body of a named location block cannot contain location blocks.
14263 FastCGI is an interface between the front-end and the back-end of a web
14264 service. It is a somewhat legacy facility; new web services should
14265 generally just talk HTTP between the front-end and the back-end.
14266 However there are a number of back-end services such as PHP or the
14267 optimized HTTP Git repository access that use FastCGI, so we have
14268 support for it in Guix.
14270 To use FastCGI, you configure the front-end web server (e.g., nginx) to
14271 dispatch some subset of its requests to the fastcgi backend, which
14272 listens on a local TCP or UNIX socket. There is an intermediary
14273 @code{fcgiwrap} program that sits between the actual backend process and
14274 the web server. The front-end indicates which backend program to run,
14275 passing that information to the @code{fcgiwrap} process.
14277 @defvr {Scheme Variable} fcgiwrap-service-type
14278 A service type for the @code{fcgiwrap} FastCGI proxy.
14281 @deftp {Data Type} fcgiwrap-configuration
14282 Data type representing the configuration of the @code{fcgiwrap} serice.
14283 This type has the following parameters:
14285 @item @code{package} (default: @code{fcgiwrap})
14286 The fcgiwrap package to use.
14288 @item @code{socket} (default: @code{tcp:127.0.0.1:9000})
14289 The socket on which the @code{fcgiwrap} process should listen, as a
14290 string. Valid @var{socket} values include
14291 @code{unix:@var{/path/to/unix/socket}},
14292 @code{tcp:@var{dot.ted.qu.ad}:@var{port}} and
14293 @code{tcp6:[@var{ipv6_addr}]:port}.
14295 @item @code{user} (default: @code{fcgiwrap})
14296 @itemx @code{group} (default: @code{fcgiwrap})
14297 The user and group names, as strings, under which to run the
14298 @code{fcgiwrap} process. The @code{fastcgi} service will ensure that if
14299 the user asks for the specific user or group names @code{fcgiwrap} that
14300 the corresponding user and/or group is present on the system.
14302 It is possible to configure a FastCGI-backed web service to pass HTTP
14303 authentication information from the front-end to the back-end, and to
14304 allow @code{fcgiwrap} to run the back-end process as a corresponding
14305 local user. To enable this capability on the back-end., run
14306 @code{fcgiwrap} as the @code{root} user and group. Note that this
14307 capability also has to be configured on the front-end as well.
14313 @subsubsection DNS Services
14314 @cindex DNS (domain name system)
14315 @cindex domain name system (DNS)
14317 The @code{(gnu services dns)} module provides services related to the
14318 @dfn{domain name system} (DNS). It provides a server service for hosting
14319 an @emph{authoritative} DNS server for multiple zones, slave or master.
14320 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
14322 An example configuration of an authoritative server for two zones, one master
14326 (define-zone-entries example.org.zone
14327 ;; Name TTL Class Type Data
14328 ("@@" "" "IN" "A" "127.0.0.1")
14329 ("@@" "" "IN" "NS" "ns")
14330 ("ns" "" "IN" "A" "127.0.0.1"))
14332 (define master-zone
14333 (knot-zone-configuration
14334 (domain "example.org")
14336 (origin "example.org")
14337 (entries example.org.zone)))))
14340 (knot-zone-configuration
14341 (domain "plop.org")
14342 (dnssec-policy "default")
14343 (master (list "plop-master"))))
14345 (define plop-master
14346 (knot-remote-configuration
14348 (address (list "208.76.58.171"))))
14352 (services (cons* (service knot-service-type
14353 (knot-confifguration
14354 (remotes (list plop-master))
14355 (zones (list master-zone slave-zone))))
14360 @deffn {Scheme Variable} knot-service-type
14361 This is the type for the Knot DNS server.
14363 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
14364 zones, that is to say domain names you would buy from a registrar. This server
14365 is not a resolver, meaning that it can only resolve names for which it is
14366 authoritative. This server can be configured to serve zones as a master server
14367 or a slave server as a per-zone basis. Slave zones will get their data from
14368 masters, and will serve it as an authoritative server. From the point of view
14369 of a resolver, there is no difference between master and slave.
14371 The following data types are used to configure the Knot DNS server:
14374 @deftp {Data Type} knot-key-configuration
14375 Data type representing a key.
14376 This type has the following parameters:
14379 @item @code{id} (default: @code{""})
14380 An identifier for other configuration fields to refer to this key. IDs must
14381 be unique and must not be empty.
14383 @item @code{algorithm} (default: @code{#f})
14384 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
14385 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
14386 and @code{'hmac-sha512}.
14388 @item @code{secret} (default: @code{""})
14389 The secret key itself.
14394 @deftp {Data Type} knot-acl-configuration
14395 Data type representing an Access Control List (ACL) configuration.
14396 This type has the following parameters:
14399 @item @code{id} (default: @code{""})
14400 An identifier for ether configuration fields to refer to this key. IDs must be
14401 unique and must not be empty.
14403 @item @code{address} (default: @code{'()})
14404 An ordered list of IP addresses, network subnets, or network ranges represented
14405 with strings. The query must match one of them. Empty value means that
14406 address match is not required.
14408 @item @code{key} (default: @code{'()})
14409 An ordered list of references to keys represented with strings. The string
14410 must match a key ID defined in a @code{knot-key-configuration}. No key means
14411 that a key is not require to match that ACL.
14413 @item @code{action} (default: @code{'()})
14414 An ordered list of actions that are permitted or forbidden by this ACL. Possible
14415 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
14416 and @code{'update}.
14418 @item @code{deny?} (default: @code{#f})
14419 When true, the ACL defines restrictions. Listed actions are forbidden. When
14420 false, listed actions are allowed.
14425 @deftp {Data Type} zone-entry
14426 Data type represnting a record entry in a zone file.
14427 This type has the following parameters:
14430 @item @code{name} (default: @code{"@@"})
14431 The name of the record. @code{"@@"} refers to the origin of the zone. Names
14432 are relative to the origin of the zone. For example, in the @code{example.org}
14433 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
14434 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
14435 refers to @code{ns.example.org}.
14437 @item @code{ttl} (default: @code{""})
14438 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
14440 @item @code{class} (default: @code{"IN"})
14441 The class of the record. Knot currently supports only @code{"IN"} and
14442 partially @code{"CH"}.
14444 @item @code{type} (default: @code{"A"})
14445 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
14446 address), NS (Name Server) and MX (Mail eXchange). Many other types are
14449 @item @code{data} (default: @code{""})
14450 The data contained in the record. For instance an IP address associated with
14451 an A record, or a domain name associated with an NS record. Remember that
14452 domain names are relative to the origin unless they end with a dot.
14457 @deftp {Data Type} zone-file
14458 Data type representing the content of a zone file.
14459 This type has the following parameters:
14462 @item @code{entries} (default: @code{'()})
14463 The list of entries. The SOA record is taken care of, so you don't need to
14464 put it in the list of entries. This list should probably contain an entry
14465 for your primary authoritative DNS server. Other than using a list of entries
14466 directly, you can use @code{define-zone-entries} to define a object containing
14467 the list of entries more easily, that you can later pass to the @code{entries}
14468 field of the @code{zone-file}.
14470 @item @code{origin} (default: @code{""})
14471 The name of your zone. This parameter cannot be empty.
14473 @item @code{ns} (default: @code{"ns"})
14474 The domain of your primary authoritative DNS server. The name is relative to
14475 the origin, unless it ends with a dot. It is mandatory that this primary
14476 DNS server corresponds to an NS record in the zone and that it is associated
14477 to an IP address in the list of entries.
14479 @item @code{mail} (default: @code{"hostmaster"})
14480 An email address people can contact you at, as the owner of the zone. This
14481 is translated as @code{<mail>@@<origin>}.
14483 @item @code{serial} (default: @code{1})
14484 The serial number of the zone. As this is used to keep track of changes by
14485 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
14486 Always increment it when you make a change in your zone.
14488 @item @code{refresh} (default: @code{(* 2 24 3600)})
14489 The frequency at which slaves will do a zone transfer. This value is a number
14490 of seconds. It can be computed by multiplications or with
14491 @code{(string->duration)}.
14493 @item @code{retry} (default: @code{(* 15 60)})
14494 The period after which a slave will retry to contact its master when it fails
14495 to do so a first time.
14497 @item @code{expiry} (default: @code{(* 14 24 3600)})
14498 Default TTL of records. Existing records are considered correct for at most
14499 this amount of time. After this period, resolvers will invalidate their cache
14500 and check again that it still exists.
14502 @item @code{nx} (default: @code{3600})
14503 Default TTL of inexistant records. This delay is usually short because you want
14504 your new domains to reach everyone quickly.
14509 @deftp {Data Type} knot-remote-configuration
14510 Data type representing a remote configuration.
14511 This type has the following parameters:
14514 @item @code{id} (default: @code{""})
14515 An identifier for other configuration fields to refer to this remote. IDs must
14516 be unique and must not be empty.
14518 @item @code{address} (default: @code{'()})
14519 An ordered list of destination IP addresses. Addresses are tried in sequence.
14520 An optional port can be given with the @@ separator. For instance:
14521 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
14523 @item @code{via} (default: @code{'()})
14524 An ordered list of source IP addresses. An empty list will have Knot choose
14525 an appropriate source IP. An optional port can be given with the @@ separator.
14526 The default is to choose at random.
14528 @item @code{key} (default: @code{#f})
14529 A reference to a key, that is a string containing the identifier of a key
14530 defined in a @code{knot-key-configuration} field.
14535 @deftp {Data Type} knot-keystore-configuration
14536 Data type representing a keystore to hold dnssec keys.
14537 This type has the following parameters:
14540 @item @code{id} (default: @code{""})
14541 The id of the keystore. It must not be empty.
14543 @item @code{backend} (default: @code{'pem})
14544 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
14546 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
14547 The configuration string of the backend. An example for the PKCS#11 is:
14548 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
14549 For the pem backend, the string reprensents a path in the filesystem.
14554 @deftp {Data Type} knot-policy-configuration
14555 Data type representing a dnssec policy. Knot DNS is able to automatically
14556 sign your zones. It can either generate and manage your keys automatically or
14557 use keys that you generate.
14559 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
14560 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
14561 zone. In order to be trusted, the KSK needs to be present in the parent zone
14562 (usually a top-level domain). If your registrar supports dnssec, you will
14563 have to send them your KSK's hash so they can add a DS record in their zone.
14564 This is not automated and need to be done each time you change your KSK.
14566 The policy also defines the lifetime of keys. Usually, ZSK can be changed
14567 easily and use weaker cryptographic functions (they use lower parameters) in
14568 order to sign records quickly, so they are changed often. The KSK however
14569 requires manual interaction with the registrar, so they are changed less often
14570 and use stronger parameters because they sign only one record.
14572 This type has the following parameters:
14575 @item @code{id} (default: @code{""})
14576 The id of the policy. It must not be empty.
14578 @item @code{keystore} (default: @code{"default"})
14579 A reference to a keystore, that is a string containing the identifier of a
14580 keystore defined in a @code{knot-keystore-configuration} field. The
14581 @code{"default"} identifier means the default keystore (a kasp database that
14582 was setup by this service).
14584 @item @code{manual?} (default: @code{#f})
14585 Whether the key management is manual or automatic.
14587 @item @code{single-type-signing?} (default: @code{#f})
14588 When @code{#t}, use the Single-Type Signing Scheme.
14590 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
14591 An algorithm of signing keys and issued signatures.
14593 @item @code{ksk-size} (default: @code{256})
14594 The length of the KSK. Note that this value is correct for the default
14595 algorithm, but would be unsecure for other algorithms.
14597 @item @code{zsk-size} (default: @code{256})
14598 The length of the ZSK. Note that this value is correct for the default
14599 algorithm, but would be unsecure for other algorithms.
14601 @item @code{dnskey-ttl} (default: @code{'default})
14602 The TTL value for DNSKEY records added into zone apex. The special
14603 @code{'default} value means same as the zone SOA TTL.
14605 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
14606 The period between ZSK publication and the next rollover initiation.
14608 @item @code{propagation-delay} (default: @code{(* 24 3600)})
14609 An extra delay added for each key rollover step. This value should be high
14610 enough to cover propagation of data from the master server to all slaves.
14612 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
14613 A validity period of newly issued signatures.
14615 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
14616 A period how long before a signature expiration the signature will be refreshed.
14618 @item @code{nsec3?} (default: @code{#f})
14619 When @code{#t}, NSEC3 will be used instead of NSEC.
14621 @item @code{nsec3-iterations} (default: @code{5})
14622 The number of additional times the hashing is performed.
14624 @item @code{nsec3-salt-length} (default: @code{8})
14625 The length of a salt field in octets, which is appended to the original owner
14626 name before hashing.
14628 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
14629 The validity period of newly issued salt field.
14634 @deftp {Data Type} knot-zone-configuration
14635 Data type representing a zone served by Knot.
14636 This type has the following parameters:
14639 @item @code{domain} (default: @code{""})
14640 The domain served by this configuration. It must not be empty.
14642 @item @code{file} (default: @code{""})
14643 The file where this zone is saved. This parameter is ignored by master zones.
14644 Empty means default location that depends on the domain name.
14646 @item @code{zone} (default: @code{(zone-file)})
14647 The content of the zone file. This parameter is ignored by slave zones. It
14648 must contain a zone-file record.
14650 @item @code{master} (default: @code{'()})
14651 A list of master remotes. When empty, this zone is a master. When set, this
14652 zone is a slave. This is a list of remotes identifiers.
14654 @item @code{ddns-master} (default: @code{#f})
14655 The main master. When empty, it defaults to the first master in the list of
14658 @item @code{notify} (default: @code{'()})
14659 A list of slave remote identifiers.
14661 @item @code{acl} (default: @code{'()})
14662 A list of acl identifiers.
14664 @item @code{semantic-checks?} (default: @code{#f})
14665 When set, this adds more semantic checks to the zone.
14667 @item @code{disable-any?} (default: @code{#f})
14668 When set, this forbids queries of the ANY type.
14670 @item @code{zonefile-sync} (default: @code{0})
14671 The delay between a modification in memory and on disk. 0 means immediate
14674 @item @code{serial-policy} (default: @code{'increment})
14675 A policy between @code{'increment} and @code{'unixtime}.
14680 @deftp {Data Type} knot-configuration
14681 Data type representing the Knot configuration.
14682 This type has the following parameters:
14685 @item @code{knot} (default: @code{knot})
14688 @item @code{run-directory} (default: @code{"/var/run/knot"})
14689 The run directory. This directory will be used for pid file and sockets.
14691 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14692 An ip address on which to listen.
14694 @item @code{listen-v6} (default: @code{"::"})
14695 An ip address on which to listen.
14697 @item @code{listen-port} (default: @code{53})
14698 A port on which to listen.
14700 @item @code{keys} (default: @code{'()})
14701 The list of knot-key-configuration used by this configuration.
14703 @item @code{acls} (default: @code{'()})
14704 The list of knot-acl-configuration used by this configuration.
14706 @item @code{remotes} (default: @code{'()})
14707 The list of knot-remote-configuration used by this configuration.
14709 @item @code{zones} (default: @code{'()})
14710 The list of knot-zone-configuration used by this configuration.
14716 @subsubsection VPN Services
14717 @cindex VPN (virtual private network)
14718 @cindex virtual private network (VPN)
14720 The @code{(gnu services vpn)} module provides services related to
14721 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14722 your machine to connect to a VPN, and a @emph{servire} service for your machine
14723 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14725 @deffn {Scheme Procedure} openvpn-client-service @
14726 [#:config (openvpn-client-configuration)]
14728 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14731 @deffn {Scheme Procedure} openvpn-server-service @
14732 [#:config (openvpn-server-configuration)]
14734 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14736 Both can be run simultaneously.
14739 @c %automatically generated documentation
14741 Available @code{openvpn-client-configuration} fields are:
14743 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14744 The OpenVPN package.
14748 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14749 The OpenVPN pid file.
14751 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14755 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14756 The protocol (UDP or TCP) used to open a channel between clients and
14759 Defaults to @samp{udp}.
14763 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14764 The device type used to represent the VPN connection.
14766 Defaults to @samp{tun}.
14770 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14771 The certificate authority to check connections against.
14773 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14777 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14778 The certificate of the machine the daemon is running on. It should be
14779 signed by the authority given in @code{ca}.
14781 Defaults to @samp{"/etc/openvpn/client.crt"}.
14785 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14786 The key of the machine the daemon is running on. It must be the key whose
14787 certificate is @code{cert}.
14789 Defaults to @samp{"/etc/openvpn/client.key"}.
14793 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14794 Whether to use the lzo compression algorithm.
14796 Defaults to @samp{#t}.
14800 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14801 Don't re-read key files across SIGUSR1 or --ping-restart.
14803 Defaults to @samp{#t}.
14807 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14808 Don't close and reopen TUN/TAP device or run up/down scripts across
14809 SIGUSR1 or --ping-restart restarts.
14811 Defaults to @samp{#t}.
14815 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14818 Defaults to @samp{3}.
14822 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14823 Add an additional layer of HMAC authentication on top of the TLS control
14824 channel to protect against DoS attacks.
14826 Defaults to @samp{#f}.
14830 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14831 Whether to check the server certificate has server usage extension.
14833 Defaults to @samp{#t}.
14837 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14838 Bind to a specific local port number.
14840 Defaults to @samp{#f}.
14844 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14845 Retry resolving server address.
14847 Defaults to @samp{#t}.
14851 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14852 A list of remote servers to connect to.
14854 Defaults to @samp{()}.
14856 Available @code{openvpn-remote-configuration} fields are:
14858 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14861 Defaults to @samp{"my-server"}.
14865 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14866 Port number the server listens to.
14868 Defaults to @samp{1194}.
14873 @c %end of automatic openvpn-client documentation
14875 @c %automatically generated documentation
14877 Available @code{openvpn-server-configuration} fields are:
14879 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14880 The OpenVPN package.
14884 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14885 The OpenVPN pid file.
14887 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14891 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14892 The protocol (UDP or TCP) used to open a channel between clients and
14895 Defaults to @samp{udp}.
14899 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14900 The device type used to represent the VPN connection.
14902 Defaults to @samp{tun}.
14906 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14907 The certificate authority to check connections against.
14909 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14913 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14914 The certificate of the machine the daemon is running on. It should be
14915 signed by the authority given in @code{ca}.
14917 Defaults to @samp{"/etc/openvpn/client.crt"}.
14921 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14922 The key of the machine the daemon is running on. It must be the key whose
14923 certificate is @code{cert}.
14925 Defaults to @samp{"/etc/openvpn/client.key"}.
14929 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14930 Whether to use the lzo compression algorithm.
14932 Defaults to @samp{#t}.
14936 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14937 Don't re-read key files across SIGUSR1 or --ping-restart.
14939 Defaults to @samp{#t}.
14943 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14944 Don't close and reopen TUN/TAP device or run up/down scripts across
14945 SIGUSR1 or --ping-restart restarts.
14947 Defaults to @samp{#t}.
14951 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14954 Defaults to @samp{3}.
14958 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14959 Add an additional layer of HMAC authentication on top of the TLS control
14960 channel to protect against DoS attacks.
14962 Defaults to @samp{#f}.
14966 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14967 Specifies the port number on which the server listens.
14969 Defaults to @samp{1194}.
14973 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14974 An ip and mask specifying the subnet inside the virtual network.
14976 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14980 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14981 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14983 Defaults to @samp{#f}.
14987 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14988 The Diffie-Hellman parameters file.
14990 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14994 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14995 The file that records client IPs.
14997 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
15001 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
15002 When true, the server will act as a gateway for its clients.
15004 Defaults to @samp{#f}.
15008 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
15009 When true, clients are allowed to talk to each other inside the VPN.
15011 Defaults to @samp{#f}.
15015 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
15016 Causes ping-like messages to be sent back and forth over the link so
15017 that each side knows when the other side has gone down. @code{keepalive}
15018 requires a pair. The first element is the period of the ping sending,
15019 and the second element is the timeout before considering the other side
15024 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
15025 The maximum number of clients.
15027 Defaults to @samp{100}.
15031 @deftypevr {@code{openvpn-server-configuration} parameter} string status
15032 The status file. This file shows a small report on current connection.
15033 It is truncated and rewritten every minute.
15035 Defaults to @samp{"/var/run/openvpn/status"}.
15039 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
15040 The list of configuration for some clients.
15042 Defaults to @samp{()}.
15044 Available @code{openvpn-ccd-configuration} fields are:
15046 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
15049 Defaults to @samp{"client"}.
15053 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
15056 Defaults to @samp{#f}.
15060 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
15063 Defaults to @samp{#f}.
15070 @c %end of automatic openvpn-server documentation
15073 @node Network File System
15074 @subsubsection Network File System
15077 The @code{(gnu services nfs)} module provides the following services,
15078 which are most commonly used in relation to mounting or exporting
15079 directory trees as @dfn{network file systems} (NFS).
15081 @subsubheading RPC Bind Service
15084 The RPC Bind service provides a facility to map program numbers into
15085 universal addresses.
15086 Many NFS related services use this facility. Hence it is automatically
15087 started when a dependent service starts.
15089 @defvr {Scheme Variable} rpcbind-service-type
15090 A service type for the RPC portmapper daemon.
15094 @deftp {Data Type} rpcbind-configuration
15095 Data type representing the configuration of the RPC Bind Service.
15096 This type has the following parameters:
15098 @item @code{rpcbind} (default: @code{rpcbind})
15099 The rpcbind package to use.
15101 @item @code{warm-start?} (default: @code{#t})
15102 If this parameter is @code{#t}, then the daemon will read a
15103 state file on startup thus reloading state information saved by a previous
15109 @subsubheading Pipefs Pseudo File System
15113 The pipefs file system is used to transfer NFS related data
15114 between the kernel and user space programs.
15116 @defvr {Scheme Variable} pipefs-service-type
15117 A service type for the pipefs pseudo file system.
15120 @deftp {Data Type} pipefs-configuration
15121 Data type representing the configuration of the pipefs pseudo file system service.
15122 This type has the following parameters:
15124 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15125 The directory to which the file system is to be attached.
15130 @subsubheading GSS Daemon Service
15133 @cindex global security system
15135 The @dfn{global security system} (GSS) daemon provides strong security for RPC
15137 Before exchanging RPC requests an RPC client must establish a security
15138 context. Typically this is done using the Kerberos command @command{kinit}
15139 or automatically at login time using PAM services (@pxref{Kerberos Services}).
15141 @defvr {Scheme Variable} gss-service-type
15142 A service type for the Global Security System (GSS) daemon.
15145 @deftp {Data Type} gss-configuration
15146 Data type representing the configuration of the GSS daemon service.
15147 This type has the following parameters:
15149 @item @code{nfs-utils} (default: @code{nfs-utils})
15150 The package in which the @command{rpc.gssd} command is to be found.
15152 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15153 The directory where the pipefs file system is mounted.
15159 @subsubheading IDMAP Daemon Service
15161 @cindex name mapper
15163 The idmap daemon service provides mapping between user IDs and user names.
15164 Typically it is required in order to access file systems mounted via NFSv4.
15166 @defvr {Scheme Variable} idmap-service-type
15167 A service type for the Identity Mapper (IDMAP) daemon.
15170 @deftp {Data Type} idmap-configuration
15171 Data type representing the configuration of the IDMAP daemon service.
15172 This type has the following parameters:
15174 @item @code{nfs-utils} (default: @code{nfs-utils})
15175 The package in which the @command{rpc.idmapd} command is to be found.
15177 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15178 The directory where the pipefs file system is mounted.
15180 @item @code{domain} (default: @code{#f})
15181 The local NFSv4 domain name.
15182 This must be a string or @code{#f}.
15183 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
15188 @node Continuous Integration
15189 @subsubsection Continuous Integration
15191 @cindex continuous integration
15192 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
15193 integration tool for Guix. It can be used both for development and for
15194 providing substitutes to others (@pxref{Substitutes}).
15196 The @code{(gnu services cuirass)} module provides the following service.
15198 @defvr {Scheme Procedure} cuirass-service-type
15199 The type of the Cuirass service. Its value must be a
15200 @code{cuirass-configuration} object, as described below.
15203 To add build jobs, you have to set the @code{specifications} field of
15204 the configuration. Here is an example of a service defining a build job
15205 based on a specification that can be found in Cuirass source tree. This
15206 service polls the Guix repository and builds a subset of the Guix
15207 packages, as prescribed in the @file{gnu-system.scm} example spec:
15210 (let ((spec #~((#:name . "guix")
15211 (#:url . "git://git.savannah.gnu.org/guix.git")
15212 (#:load-path . ".")
15214 ;; Here we must provide an absolute file name.
15215 ;; We take jobs from one of the examples provided
15217 (#:file . #$(file-append
15219 "/tests/gnu-system.scm"))
15221 (#:proc . hydra-jobs)
15222 (#:arguments (subset . "hello"))
15223 (#:branch . "master"))))
15224 (service cuirass-service-type
15225 (cuirass-configuration
15226 (specifications #~(list #$spec)))))
15229 While information related to build jobs is located directly in the
15230 specifications, global settings for the @command{cuirass} process are
15231 accessible in other @code{cuirass-configuration} fields.
15233 @deftp {Data Type} cuirass-configuration
15234 Data type representing the configuration of Cuirass.
15237 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
15238 Location of the log file.
15240 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
15241 Location of the repository cache.
15243 @item @code{user} (default: @code{"cuirass"})
15244 Owner of the @code{cuirass} process.
15246 @item @code{group} (default: @code{"cuirass"})
15247 Owner's group of the @code{cuirass} process.
15249 @item @code{interval} (default: @code{60})
15250 Number of seconds between the poll of the repositories followed by the
15253 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
15254 Location of sqlite database which contains the build results and previously
15255 added specifications.
15257 @item @code{port} (default: @code{8080})
15258 Port number used by the HTTP server.
15260 @item @code{specifications} (default: @code{#~'()})
15261 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
15262 where a specification is an association list
15263 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
15264 keys are keywords (@code{#:keyword-example}) as shown in the example
15267 @item @code{use-substitutes?} (default: @code{#f})
15268 This allows using substitutes to avoid building every dependencies of a job
15271 @item @code{one-shot?} (default: @code{#f})
15272 Only evaluate specifications and build derivations once.
15274 @item @code{fallback?} (default: @code{#f})
15275 When substituting a pre-built binary fails, fall back to building
15278 @item @code{load-path} (default: @code{'()})
15279 This allows users to define their own packages and make them visible to
15280 cuirass as in @command{guix build} command.
15282 @item @code{cuirass} (default: @code{cuirass})
15283 The Cuirass package to use.
15287 @node Power management Services
15288 @subsubsection Power management Services
15290 @cindex power management with TLP
15291 The @code{(gnu services pm)} module provides a Guix service definition
15292 for the Linux power management tool TLP.
15294 TLP enables various powersaving modes in userspace and kernel.
15295 Contrary to @code{upower-service}, it is not a passive,
15296 monitoring tool, as it will apply custom settings each time a new power
15297 source is detected. More information can be found at
15298 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
15300 @deffn {Scheme Variable} tlp-service-type
15301 The service type for the TLP tool. Its value should be a valid
15302 TLP configuration (see below). To use the default settings, simply
15305 (service tlp-service-type)
15309 By default TLP does not need much configuration but most TLP parameters
15310 can be tweaked using @code{tlp-configuration}.
15312 Each parameter definition is preceded by its type; for example,
15313 @samp{boolean foo} indicates that the @code{foo} parameter
15314 should be specified as a boolean. Types starting with
15315 @code{maybe-} denote parameters that won't show up in TLP config file
15316 when their value is @code{'disabled}.
15318 @c The following documentation was initially generated by
15319 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
15320 @c documentation is better, so we shouldn't hesitate to edit below as
15321 @c needed. However if the change you want to make to this documentation
15322 @c can be done in an automated way, it's probably easier to change
15323 @c (generate-documentation) than to make it below and have to deal with
15324 @c the churn as TLP updates.
15326 Available @code{tlp-configuration} fields are:
15328 @deftypevr {@code{tlp-configuration} parameter} package tlp
15333 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
15334 Set to true if you wish to enable TLP.
15336 Defaults to @samp{#t}.
15340 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
15341 Default mode when no power supply can be detected. Alternatives are AC
15344 Defaults to @samp{"AC"}.
15348 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
15349 Number of seconds Linux kernel has to wait after the disk goes idle,
15350 before syncing on AC.
15352 Defaults to @samp{0}.
15356 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
15357 Same as @code{disk-idle-ac} but on BAT mode.
15359 Defaults to @samp{2}.
15363 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
15364 Dirty pages flushing periodicity, expressed in seconds.
15366 Defaults to @samp{15}.
15370 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
15371 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
15373 Defaults to @samp{60}.
15377 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
15378 CPU frequency scaling governor on AC mode. With intel_pstate driver,
15379 alternatives are powersave and performance. With acpi-cpufreq driver,
15380 alternatives are ondemand, powersave, performance and conservative.
15382 Defaults to @samp{disabled}.
15386 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
15387 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
15389 Defaults to @samp{disabled}.
15393 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
15394 Set the min available frequency for the scaling governor on AC.
15396 Defaults to @samp{disabled}.
15400 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
15401 Set the max available frequency for the scaling governor on AC.
15403 Defaults to @samp{disabled}.
15407 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
15408 Set the min available frequency for the scaling governor on BAT.
15410 Defaults to @samp{disabled}.
15414 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
15415 Set the max available frequency for the scaling governor on BAT.
15417 Defaults to @samp{disabled}.
15421 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
15422 Limit the min P-state to control the power dissipation of the CPU, in AC
15423 mode. Values are stated as a percentage of the available performance.
15425 Defaults to @samp{disabled}.
15429 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
15430 Limit the max P-state to control the power dissipation of the CPU, in AC
15431 mode. Values are stated as a percentage of the available performance.
15433 Defaults to @samp{disabled}.
15437 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
15438 Same as @code{cpu-min-perf-on-ac} on BAT mode.
15440 Defaults to @samp{disabled}.
15444 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
15445 Same as @code{cpu-max-perf-on-ac} on BAT mode.
15447 Defaults to @samp{disabled}.
15451 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
15452 Enable CPU turbo boost feature on AC mode.
15454 Defaults to @samp{disabled}.
15458 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
15459 Same as @code{cpu-boost-on-ac?} on BAT mode.
15461 Defaults to @samp{disabled}.
15465 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
15466 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
15467 used under light load conditions.
15469 Defaults to @samp{#f}.
15473 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
15474 Same as @code{sched-powersave-on-ac?} but on BAT mode.
15476 Defaults to @samp{#t}.
15480 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
15481 Enable Linux kernel NMI watchdog.
15483 Defaults to @samp{#f}.
15487 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
15488 For Linux kernels with PHC patch applied, change CPU voltages. An
15489 example value would be @samp{"F:V F:V F:V F:V"}.
15491 Defaults to @samp{disabled}.
15495 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
15496 Set CPU performance versus energy saving policy on AC. Alternatives are
15497 performance, normal, powersave.
15499 Defaults to @samp{"performance"}.
15503 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
15504 Same as @code{energy-perf-policy-ac} but on BAT mode.
15506 Defaults to @samp{"powersave"}.
15510 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
15515 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
15516 Hard disk advanced power management level.
15520 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
15521 Same as @code{disk-apm-bat} but on BAT mode.
15525 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
15526 Hard disk spin down timeout. One value has to be specified for each
15527 declared hard disk.
15529 Defaults to @samp{disabled}.
15533 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
15534 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
15536 Defaults to @samp{disabled}.
15540 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
15541 Select IO scheduler for disk devices. One value has to be specified for
15542 each declared hard disk. Example alternatives are cfq, deadline and
15545 Defaults to @samp{disabled}.
15549 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
15550 SATA aggressive link power management (ALPM) level. Alternatives are
15551 min_power, medium_power, max_performance.
15553 Defaults to @samp{"max_performance"}.
15557 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
15558 Same as @code{sata-linkpwr-ac} but on BAT mode.
15560 Defaults to @samp{"min_power"}.
15564 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
15565 Exclude specified SATA host devices for link power management.
15567 Defaults to @samp{disabled}.
15571 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
15572 Enable Runtime Power Management for AHCI controller and disks on AC
15575 Defaults to @samp{disabled}.
15579 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
15580 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
15582 Defaults to @samp{disabled}.
15586 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
15587 Seconds of inactivity before disk is suspended.
15589 Defaults to @samp{15}.
15593 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
15594 PCI Express Active State Power Management level. Alternatives are
15595 default, performance, powersave.
15597 Defaults to @samp{"performance"}.
15601 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
15602 Same as @code{pcie-aspm-ac} but on BAT mode.
15604 Defaults to @samp{"powersave"}.
15608 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
15609 Radeon graphics clock speed level. Alternatives are low, mid, high,
15612 Defaults to @samp{"high"}.
15616 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
15617 Same as @code{radeon-power-ac} but on BAT mode.
15619 Defaults to @samp{"low"}.
15623 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
15624 Radeon dynamic power management method (DPM). Alternatives are battery,
15627 Defaults to @samp{"performance"}.
15631 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
15632 Same as @code{radeon-dpm-state-ac} but on BAT mode.
15634 Defaults to @samp{"battery"}.
15638 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
15639 Radeon DPM performance level. Alternatives are auto, low, high.
15641 Defaults to @samp{"auto"}.
15645 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
15646 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
15648 Defaults to @samp{"auto"}.
15652 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
15653 Wifi power saving mode.
15655 Defaults to @samp{#f}.
15659 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
15660 Same as @code{wifi-power-ac?} but on BAT mode.
15662 Defaults to @samp{#t}.
15666 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
15667 Disable wake on LAN.
15669 Defaults to @samp{#t}.
15673 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
15674 Timeout duration in seconds before activating audio power saving on
15675 Intel HDA and AC97 devices. A value of 0 disables power saving.
15677 Defaults to @samp{0}.
15681 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
15682 Same as @code{sound-powersave-ac} but on BAT mode.
15684 Defaults to @samp{1}.
15688 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15689 Disable controller in powersaving mode on Intel HDA devices.
15691 Defaults to @samp{#t}.
15695 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15696 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15697 powered on again by releasing (and reinserting) the eject lever or by
15698 pressing the disc eject button on newer models.
15700 Defaults to @samp{#f}.
15704 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15705 Name of the optical drive device to power off.
15707 Defaults to @samp{"sr0"}.
15711 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15712 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15715 Defaults to @samp{"on"}.
15719 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15720 Same as @code{runtime-pm-ac} but on BAT mode.
15722 Defaults to @samp{"auto"}.
15726 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15727 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15730 Defaults to @samp{#t}.
15734 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15735 Exclude specified PCI(e) device addresses from Runtime Power Management.
15737 Defaults to @samp{disabled}.
15741 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15742 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15747 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15748 Enable USB autosuspend feature.
15750 Defaults to @samp{#t}.
15754 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15755 Exclude specified devices from USB autosuspend.
15757 Defaults to @samp{disabled}.
15761 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15762 Exclude WWAN devices from USB autosuspend.
15764 Defaults to @samp{#t}.
15768 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15769 Include specified devices into USB autosuspend, even if they are already
15770 excluded by the driver or via @code{usb-blacklist-wwan?}.
15772 Defaults to @samp{disabled}.
15776 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15777 Enable USB autosuspend before shutdown.
15779 Defaults to @samp{disabled}.
15783 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15784 Restore radio device state (bluetooth, wifi, wwan) from previous
15785 shutdown on system startup.
15787 Defaults to @samp{#f}.
15792 The @code{(gnu services pm)} module provides an interface to
15793 thermald, a CPU frequency scaling service which helps prevent overheating.
15795 @defvr {Scheme Variable} thermald-service-type
15796 This is the service type for
15797 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15798 Thermal Daemon, which is responsible for controlling the thermal state
15799 of processors and preventing overheating.
15802 @deftp {Data Type} thermald-configuration
15803 Data type representing the configuration of @code{thermald-service-type}.
15806 @item @code{ignore-cpuid-check?} (default: @code{#f})
15807 Ignore cpuid check for supported CPU models.
15809 @item @code{thermald} (default: @var{thermald})
15810 Package object of thermald.
15815 @node Audio Services
15816 @subsubsection Audio Services
15818 The @code{(gnu services audio)} module provides a service to start MPD
15819 (the Music Player Daemon).
15822 @subsubheading Music Player Daemon
15824 The Music Player Daemon (MPD) is a service that can play music while
15825 being controlled from the local machine or over the network by a variety
15828 The following example shows how one might run @code{mpd} as user
15829 @code{"bob"} on port @code{6666}. It uses pulseaudio for output.
15832 (service mpd-service-type
15838 @defvr {Scheme Variable} mpd-service-type
15839 The service type for @command{mpd}
15842 @deftp {Data Type} mpd-configuration
15843 Data type representing the configuration of @command{mpd}.
15846 @item @code{user} (default: @code{"mpd"})
15847 The user to run mpd as.
15849 @item @code{music-dir} (default: @code{"~/Music"})
15850 The directory to scan for music files.
15852 @item @code{playlist-dir} (default: @code{"~/.mpd/playlists"})
15853 The directory to store playlists.
15855 @item @code{port} (default: @code{"6600"})
15856 The port to run mpd on.
15858 @item @code{address} (default: @code{"any"})
15859 The address that mpd will bind to. To use a Unix domain socket,
15860 an absolute path can be specified here.
15865 @node Virtualization Services
15866 @subsubsection Virtualization services
15867 The @code{(gnu services virtualization)} module provides services for
15868 the libvirt and virtlog daemons.
15870 @subsubheading Libvirt daemon
15871 @code{libvirtd} is the server side daemon component of the libvirt
15872 virtualization management system. This daemon runs on host servers
15873 and performs required management tasks for virtualized guests.
15875 @deffn {Scheme Variable} libvirt-service-type
15876 This is the type of the @uref{https://libvirt.org, libvirt daemon}.
15877 Its value must be a @code{libvirt-configuration}.
15880 (service libvirt-service-type
15881 (libvirt-configuration
15882 (unix-sock-group "libvirt")
15883 (tls-port "16555")))
15887 @c Auto-generated with (generate-libvirt-documentation)
15888 Available @code{libvirt-configuration} fields are:
15890 @deftypevr {@code{libvirt-configuration} parameter} package libvirt
15895 @deftypevr {@code{libvirt-configuration} parameter} boolean listen-tls?
15896 Flag listening for secure TLS connections on the public TCP/IP port.
15897 must set @code{listen} for this to have any effect.
15899 It is necessary to setup a CA and issue server certificates before using
15902 Defaults to @samp{#t}.
15906 @deftypevr {@code{libvirt-configuration} parameter} boolean listen-tcp?
15907 Listen for unencrypted TCP connections on the public TCP/IP port. must
15908 set @code{listen} for this to have any effect.
15910 Using the TCP socket requires SASL authentication by default. Only SASL
15911 mechanisms which support data encryption are allowed. This is
15912 DIGEST_MD5 and GSSAPI (Kerberos5)
15914 Defaults to @samp{#f}.
15918 @deftypevr {@code{libvirt-configuration} parameter} string tls-port
15919 Port for accepting secure TLS connections This can be a port number, or
15922 Defaults to @samp{"16514"}.
15926 @deftypevr {@code{libvirt-configuration} parameter} string tcp-port
15927 Port for accepting insecure TCP connections This can be a port number,
15930 Defaults to @samp{"16509"}.
15934 @deftypevr {@code{libvirt-configuration} parameter} string listen-addr
15935 IP address or hostname used for client connections.
15937 Defaults to @samp{"0.0.0.0"}.
15941 @deftypevr {@code{libvirt-configuration} parameter} boolean mdns-adv?
15942 Flag toggling mDNS advertisement of the libvirt service.
15944 Alternatively can disable for all services on a host by stopping the
15947 Defaults to @samp{#f}.
15951 @deftypevr {@code{libvirt-configuration} parameter} string mdns-name
15952 Default mDNS advertisement name. This must be unique on the immediate
15955 Defaults to @samp{"Virtualization Host <hostname>"}.
15959 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-group
15960 UNIX domain socket group ownership. This can be used to allow a
15961 'trusted' set of users access to management capabilities without
15964 Defaults to @samp{"root"}.
15968 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-ro-perms
15969 UNIX socket permissions for the R/O socket. This is used for monitoring
15972 Defaults to @samp{"0777"}.
15976 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-rw-perms
15977 UNIX socket permissions for the R/W socket. Default allows only root.
15978 If PolicyKit is enabled on the socket, the default will change to allow
15979 everyone (eg, 0777)
15981 Defaults to @samp{"0770"}.
15985 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-admin-perms
15986 UNIX socket permissions for the admin socket. Default allows only owner
15987 (root), do not change it unless you are sure to whom you are exposing
15990 Defaults to @samp{"0777"}.
15994 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-dir
15995 The directory in which sockets will be found/created.
15997 Defaults to @samp{"/var/run/libvirt"}.
16001 @deftypevr {@code{libvirt-configuration} parameter} string auth-unix-ro
16002 Authentication scheme for UNIX read-only sockets. By default socket
16003 permissions allow anyone to connect
16005 Defaults to @samp{"polkit"}.
16009 @deftypevr {@code{libvirt-configuration} parameter} string auth-unix-rw
16010 Authentication scheme for UNIX read-write sockets. By default socket
16011 permissions only allow root. If PolicyKit support was compiled into
16012 libvirt, the default will be to use 'polkit' auth.
16014 Defaults to @samp{"polkit"}.
16018 @deftypevr {@code{libvirt-configuration} parameter} string auth-tcp
16019 Authentication scheme for TCP sockets. If you don't enable SASL, then
16020 all TCP traffic is cleartext. Don't do this outside of a dev/test
16023 Defaults to @samp{"sasl"}.
16027 @deftypevr {@code{libvirt-configuration} parameter} string auth-tls
16028 Authentication scheme for TLS sockets. TLS sockets already have
16029 encryption provided by the TLS layer, and limited authentication is done
16032 It is possible to make use of any SASL authentication mechanism as well,
16033 by using 'sasl' for this option
16035 Defaults to @samp{"none"}.
16039 @deftypevr {@code{libvirt-configuration} parameter} optional-list access-drivers
16040 API access control scheme.
16042 By default an authenticated user is allowed access to all APIs. Access
16043 drivers can place restrictions on this.
16045 Defaults to @samp{()}.
16049 @deftypevr {@code{libvirt-configuration} parameter} string key-file
16050 Server key file path. If set to an empty string, then no private key is
16053 Defaults to @samp{""}.
16057 @deftypevr {@code{libvirt-configuration} parameter} string cert-file
16058 Server key file path. If set to an empty string, then no certificate is
16061 Defaults to @samp{""}.
16065 @deftypevr {@code{libvirt-configuration} parameter} string ca-file
16066 Server key file path. If set to an empty string, then no CA certificate
16069 Defaults to @samp{""}.
16073 @deftypevr {@code{libvirt-configuration} parameter} string crl-file
16074 Certificate revocation list path. If set to an empty string, then no
16077 Defaults to @samp{""}.
16081 @deftypevr {@code{libvirt-configuration} parameter} boolean tls-no-sanity-cert
16082 Disable verification of our own server certificates.
16084 When libvirtd starts it performs some sanity checks against its own
16087 Defaults to @samp{#f}.
16091 @deftypevr {@code{libvirt-configuration} parameter} boolean tls-no-verify-cert
16092 Disable verification of client certificates.
16094 Client certificate verification is the primary authentication mechanism.
16095 Any client which does not present a certificate signed by the CA will be
16098 Defaults to @samp{#f}.
16102 @deftypevr {@code{libvirt-configuration} parameter} optional-list tls-allowed-dn-list
16103 Whitelist of allowed x509 Distinguished Name.
16105 Defaults to @samp{()}.
16109 @deftypevr {@code{libvirt-configuration} parameter} optional-list sasl-allowed-usernames
16110 Whitelist of allowed SASL usernames. The format for username depends on
16111 the SASL authentication mechanism.
16113 Defaults to @samp{()}.
16117 @deftypevr {@code{libvirt-configuration} parameter} string tls-priority
16118 Override the compile time default TLS priority string. The default is
16119 usually "NORMAL" unless overridden at build time. Only set this is it
16120 is desired for libvirt to deviate from the global default settings.
16122 Defaults to @samp{"NORMAL"}.
16126 @deftypevr {@code{libvirt-configuration} parameter} integer max-clients
16127 Maximum number of concurrent client connections to allow over all
16130 Defaults to @samp{5000}.
16134 @deftypevr {@code{libvirt-configuration} parameter} integer max-queued-clients
16135 Maximum length of queue of connections waiting to be accepted by the
16136 daemon. Note, that some protocols supporting retransmission may obey
16137 this so that a later reattempt at connection succeeds.
16139 Defaults to @samp{1000}.
16143 @deftypevr {@code{libvirt-configuration} parameter} integer max-anonymous-clients
16144 Maximum length of queue of accepted but not yet authenticated clients.
16145 Set this to zero to turn this feature off
16147 Defaults to @samp{20}.
16151 @deftypevr {@code{libvirt-configuration} parameter} integer min-workers
16152 Number of workers to start up initially.
16154 Defaults to @samp{5}.
16158 @deftypevr {@code{libvirt-configuration} parameter} integer max-workers
16159 Maximum number of worker threads.
16161 If the number of active clients exceeds @code{min-workers}, then more
16162 threads are spawned, up to max_workers limit. Typically you'd want
16163 max_workers to equal maximum number of clients allowed.
16165 Defaults to @samp{20}.
16169 @deftypevr {@code{libvirt-configuration} parameter} integer prio-workers
16170 Number of priority workers. If all workers from above pool are stuck,
16171 some calls marked as high priority (notably domainDestroy) can be
16172 executed in this pool.
16174 Defaults to @samp{5}.
16178 @deftypevr {@code{libvirt-configuration} parameter} integer max-requests
16179 Total global limit on concurrent RPC calls.
16181 Defaults to @samp{20}.
16185 @deftypevr {@code{libvirt-configuration} parameter} integer max-client-requests
16186 Limit on concurrent requests from a single client connection. To avoid
16187 one client monopolizing the server this should be a small fraction of
16188 the global max_requests and max_workers parameter.
16190 Defaults to @samp{5}.
16194 @deftypevr {@code{libvirt-configuration} parameter} integer admin-min-workers
16195 Same as @code{min-workers} but for the admin interface.
16197 Defaults to @samp{1}.
16201 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-workers
16202 Same as @code{max-workers} but for the admin interface.
16204 Defaults to @samp{5}.
16208 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-clients
16209 Same as @code{max-clients} but for the admin interface.
16211 Defaults to @samp{5}.
16215 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-queued-clients
16216 Same as @code{max-queued-clients} but for the admin interface.
16218 Defaults to @samp{5}.
16222 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-client-requests
16223 Same as @code{max-client-requests} but for the admin interface.
16225 Defaults to @samp{5}.
16229 @deftypevr {@code{libvirt-configuration} parameter} integer log-level
16230 Logging level. 4 errors, 3 warnings, 2 information, 1 debug.
16232 Defaults to @samp{3}.
16236 @deftypevr {@code{libvirt-configuration} parameter} string log-filters
16239 A filter allows to select a different logging level for a given category
16240 of logs The format for a filter is one of:
16251 where @code{name} is a string which is matched against the category
16252 given in the @code{VIR_LOG_INIT()} at the top of each libvirt source
16253 file, e.g., "remote", "qemu", or "util.json" (the name in the filter can
16254 be a substring of the full category name, in order to match multiple
16255 similar categories), the optional "+" prefix tells libvirt to log stack
16256 trace for each message matching name, and @code{x} is the minimal level
16257 where matching messages should be logged:
16274 Multiple filters can be defined in a single filters statement, they just
16275 need to be separated by spaces.
16277 Defaults to @samp{"3:remote 4:event"}.
16281 @deftypevr {@code{libvirt-configuration} parameter} string log-outputs
16284 An output is one of the places to save logging information The format
16285 for an output can be:
16289 output goes to stderr
16291 @item x:syslog:name
16292 use syslog for the output and use the given name as the ident
16294 @item x:file:file_path
16295 output to a file, with the given filepath
16298 output to journald logging system
16302 In all case the x prefix is the minimal level, acting as a filter
16319 Multiple outputs can be defined, they just need to be separated by
16322 Defaults to @samp{"3:stderr"}.
16326 @deftypevr {@code{libvirt-configuration} parameter} integer audit-level
16327 Allows usage of the auditing subsystem to be altered
16331 0: disable all auditing
16334 1: enable auditing, only if enabled on host
16337 2: enable auditing, and exit if disabled on host.
16341 Defaults to @samp{1}.
16345 @deftypevr {@code{libvirt-configuration} parameter} boolean audit-logging
16346 Send audit messages via libvirt logging infrastructure.
16348 Defaults to @samp{#f}.
16352 @deftypevr {@code{libvirt-configuration} parameter} optional-string host-uuid
16353 Host UUID. UUID must not have all digits be the same.
16355 Defaults to @samp{""}.
16359 @deftypevr {@code{libvirt-configuration} parameter} string host-uuid-source
16360 Source to read host UUID.
16364 @code{smbios}: fetch the UUID from @code{dmidecode -s system-uuid}
16367 @code{machine-id}: fetch the UUID from @code{/etc/machine-id}
16371 If @code{dmidecode} does not provide a valid UUID a temporary UUID will
16374 Defaults to @samp{"smbios"}.
16378 @deftypevr {@code{libvirt-configuration} parameter} integer keepalive-interval
16379 A keepalive message is sent to a client after @code{keepalive_interval}
16380 seconds of inactivity to check if the client is still responding. If
16381 set to -1, libvirtd will never send keepalive requests; however clients
16382 can still send them and the daemon will send responses.
16384 Defaults to @samp{5}.
16388 @deftypevr {@code{libvirt-configuration} parameter} integer keepalive-count
16389 Maximum number of keepalive messages that are allowed to be sent to the
16390 client without getting any response before the connection is considered
16393 In other words, the connection is automatically closed approximately
16394 after @code{keepalive_interval * (keepalive_count + 1)} seconds since
16395 the last message received from the client. When @code{keepalive-count}
16396 is set to 0, connections will be automatically closed after
16397 @code{keepalive-interval} seconds of inactivity without sending any
16398 keepalive messages.
16400 Defaults to @samp{5}.
16404 @deftypevr {@code{libvirt-configuration} parameter} integer admin-keepalive-interval
16405 Same as above but for admin interface.
16407 Defaults to @samp{5}.
16411 @deftypevr {@code{libvirt-configuration} parameter} integer admin-keepalive-count
16412 Same as above but for admin interface.
16414 Defaults to @samp{5}.
16418 @deftypevr {@code{libvirt-configuration} parameter} integer ovs-timeout
16419 Timeout for Open vSwitch calls.
16421 The @code{ovs-vsctl} utility is used for the configuration and its
16422 timeout option is set by default to 5 seconds to avoid potential
16423 infinite waits blocking libvirt.
16425 Defaults to @samp{5}.
16429 @c %end of autogenerated docs
16431 @subsubheading Virtlog daemon
16432 The virtlogd service is a server side daemon component of libvirt that is
16433 used to manage logs from virtual machine consoles.
16435 This daemon is not used directly by libvirt client applications, rather it
16436 is called on their behalf by @code{libvirtd}. By maintaining the logs in a
16437 standalone daemon, the main @code{libvirtd} daemon can be restarted without
16438 risk of losing logs. The @code{virtlogd} daemon has the ability to re-exec()
16439 itself upon receiving @code{SIGUSR1}, to allow live upgrades without downtime.
16441 @deffn {Scheme Variable} virtlog-service-type
16442 This is the type of the virtlog daemon.
16443 Its value must be a @code{virtlog-configuration}.
16446 (service virtlog-service-type
16447 (virtlog-configuration
16448 (max-clients 1000)))
16452 @deftypevr {@code{virtlog-configuration} parameter} integer log-level
16453 Logging level. 4 errors, 3 warnings, 2 information, 1 debug.
16455 Defaults to @samp{3}.
16459 @deftypevr {@code{virtlog-configuration} parameter} string log-filters
16462 A filter allows to select a different logging level for a given category
16463 of logs The format for a filter is one of:
16474 where @code{name} is a string which is matched against the category
16475 given in the @code{VIR_LOG_INIT()} at the top of each libvirt source
16476 file, e.g., "remote", "qemu", or "util.json" (the name in the filter can
16477 be a substring of the full category name, in order to match multiple
16478 similar categories), the optional "+" prefix tells libvirt to log stack
16479 trace for each message matching name, and @code{x} is the minimal level
16480 where matching messages should be logged:
16497 Multiple filters can be defined in a single filters statement, they just
16498 need to be separated by spaces.
16500 Defaults to @samp{"3:remote 4:event"}.
16504 @deftypevr {@code{virtlog-configuration} parameter} string log-outputs
16507 An output is one of the places to save logging information The format
16508 for an output can be:
16512 output goes to stderr
16514 @item x:syslog:name
16515 use syslog for the output and use the given name as the ident
16517 @item x:file:file_path
16518 output to a file, with the given filepath
16521 output to journald logging system
16525 In all case the x prefix is the minimal level, acting as a filter
16542 Multiple outputs can be defined, they just need to be separated by
16545 Defaults to @samp{"3:stderr"}.
16549 @deftypevr {@code{virtlog-configuration} parameter} integer max-clients
16550 Maximum number of concurrent client connections to allow over all
16553 Defaults to @samp{1024}.
16557 @deftypevr {@code{virtlog-configuration} parameter} integer max-size
16558 Maximum file size before rolling over.
16560 Defaults to @samp{2MB}
16564 @deftypevr {@code{virtlog-configuration} parameter} integer max-backups
16565 Maximum number of backup files to keep.
16567 Defaults to @samp{3}
16572 @node Miscellaneous Services
16573 @subsubsection Miscellaneous Services
16576 @subsubheading System Control Service
16578 The @code{(gnu services sysctl)} provides a service to configure kernel
16579 parameters at boot.
16581 @defvr {Scheme Variable} sysctl-service-type
16582 The service type for @command{sysctl}, which modifies kernel parameters
16583 under @file{/proc/sys/}. To enable IPv4 forwarding, it can be
16587 (service sysctl-service-type
16588 (sysctl-configuration
16589 (settings '(("net.ipv4.ip_forward" . "1")))))
16593 @deftp {Data Type} sysctl-configuration
16594 The data type representing the configuration of @command{sysctl}.
16597 @item @code{sysctl} (default: @code{(file-append procps "/sbin/sysctl"})
16598 The @command{sysctl} executable to use.
16600 @item @code{settings} (default: @code{'()})
16601 An association list specifies kernel parameters and their values.
16606 @subsubheading Lirc Service
16608 The @code{(gnu services lirc)} module provides the following service.
16610 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
16611 [#:device #f] [#:driver #f] [#:config-file #f] @
16612 [#:extra-options '()]
16613 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
16614 decodes infrared signals from remote controls.
16616 Optionally, @var{device}, @var{driver} and @var{config-file}
16617 (configuration file name) may be specified. See @command{lircd} manual
16620 Finally, @var{extra-options} is a list of additional command-line options
16621 passed to @command{lircd}.
16625 @subsubheading Spice Service
16627 The @code{(gnu services spice)} module provides the following service.
16629 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
16630 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
16631 that enables sharing the clipboard with a vm and setting the guest display
16632 resolution when the graphical console window resizes.
16635 @subsubsection Dictionary Services
16637 The @code{(gnu services dict)} module provides the following service:
16639 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
16640 Return a service that runs the @command{dicod} daemon, an implementation
16641 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
16643 The optional @var{config} argument specifies the configuration for
16644 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
16645 default it serves the GNU Collaborative International Dictonary of English.
16647 You can add @command{open localhost} to your @file{~/.dico} file to make
16648 @code{localhost} the default server for @command{dico} client
16649 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
16652 @deftp {Data Type} dicod-configuration
16653 Data type representing the configuration of dicod.
16656 @item @code{dico} (default: @var{dico})
16657 Package object of the GNU Dico dictionary server.
16659 @item @code{interfaces} (default: @var{'("localhost")})
16660 This is the list of IP addresses and ports and possibly socket file
16661 names to listen to (@pxref{Server Settings, @code{listen} directive,,
16662 dico, GNU Dico Manual}).
16664 @item @code{handlers} (default: @var{'()})
16665 List of @code{<dicod-handler>} objects denoting handlers (module instances).
16667 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
16668 List of @code{<dicod-database>} objects denoting dictionaries to be served.
16672 @deftp {Data Type} dicod-handler
16673 Data type representing a dictionary handler (module instance).
16677 Name of the handler (module instance).
16679 @item @code{module} (default: @var{#f})
16680 Name of the dicod module of the handler (instance). If it is @code{#f},
16681 the module has the same name as the handler.
16682 (@pxref{Modules,,, dico, GNU Dico Manual}).
16684 @item @code{options}
16685 List of strings or gexps representing the arguments for the module handler
16689 @deftp {Data Type} dicod-database
16690 Data type representing a dictionary database.
16694 Name of the database, will be used in DICT commands.
16696 @item @code{handler}
16697 Name of the dicod handler (module instance) used by this database
16698 (@pxref{Handlers,,, dico, GNU Dico Manual}).
16700 @item @code{complex?} (default: @var{#f})
16701 Whether the database configuration complex. The complex configuration
16702 will need a corresponding @code{<dicod-handler>} object, otherwise not.
16704 @item @code{options}
16705 List of strings or gexps representing the arguments for the database
16706 (@pxref{Databases,,, dico, GNU Dico Manual}).
16710 @defvr {Scheme Variable} %dicod-database:gcide
16711 A @code{<dicod-database>} object serving the GNU Collaborative International
16712 Dictionary of English using the @code{gcide} package.
16715 The following is an example @code{dicod-service} configuration.
16718 (dicod-service #:config
16719 (dicod-configuration
16720 (handlers (list (dicod-handler
16724 (list #~(string-append "dbdir=" #$wordnet))))))
16725 (databases (list (dicod-database
16728 (handler "wordnet")
16729 (options '("database=wn")))
16730 %dicod-database:gcide))))
16733 @subsubsection Version Control
16735 The @code{(gnu services version-control)} module provides the following services:
16737 @subsubheading Git daemon service
16739 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
16741 Return a service that runs @command{git daemon}, a simple TCP server to
16742 expose repositories over the Git protocol for anonymous access.
16744 The optional @var{config} argument should be a
16745 @code{<git-daemon-configuration>} object, by default it allows read-only
16746 access to exported@footnote{By creating the magic file
16747 "git-daemon-export-ok" in the repository directory.} repositories under
16752 @deftp {Data Type} git-daemon-configuration
16753 Data type representing the configuration for @code{git-daemon-service}.
16756 @item @code{package} (default: @var{git})
16757 Package object of the Git distributed version control system.
16759 @item @code{export-all?} (default: @var{#f})
16760 Whether to allow access for all Git repositories, even if they do not
16761 have the @file{git-daemon-export-ok} file.
16763 @item @code{base-path} (default: @file{/srv/git})
16764 Whether to remap all the path requests as relative to the given path.
16765 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
16766 then if you later try to pull @code{git://example.com/hello.git}, git
16767 daemon will interpret the path as @code{/srv/git/hello.git}.
16769 @item @code{user-path} (default: @var{#f})
16770 Whether to allow @code{~user} notation to be used in requests. When
16771 specified with empty string, requests to @code{git://host/~alice/foo} is
16772 taken as a request to access @code{foo} repository in the home directory
16773 of user @code{alice}. If @var{(user-path "path")} is specified, the
16774 same request is taken as a request to access @code{path/foo} repository
16775 in the home directory of user @code{alice}.
16777 @item @code{listen} (default: @var{'()})
16778 Whether to listen on specific IP addresses or hostnames, defaults to
16781 @item @code{port} (default: @var{#f})
16782 Whether to listen on an alternative port, which defaults to 9418.
16784 @item @code{whitelist} (default: @var{'()})
16785 If not empty, only allow access to this list of directories.
16787 @item @code{extra-options} (default: @var{'()})
16788 Extra options will be passed to @code{git daemon}, please run
16789 @command{man git-daemon} for more information.
16794 @node Setuid Programs
16795 @subsection Setuid Programs
16797 @cindex setuid programs
16798 Some programs need to run with ``root'' privileges, even when they are
16799 launched by unprivileged users. A notorious example is the
16800 @command{passwd} program, which users can run to change their
16801 password, and which needs to access the @file{/etc/passwd} and
16802 @file{/etc/shadow} files---something normally restricted to root, for
16803 obvious security reasons. To address that, these executables are
16804 @dfn{setuid-root}, meaning that they always run with root privileges
16805 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
16806 for more info about the setuid mechanism.)
16808 The store itself @emph{cannot} contain setuid programs: that would be a
16809 security issue since any user on the system can write derivations that
16810 populate the store (@pxref{The Store}). Thus, a different mechanism is
16811 used: instead of changing the setuid bit directly on files that are in
16812 the store, we let the system administrator @emph{declare} which programs
16813 should be setuid root.
16815 The @code{setuid-programs} field of an @code{operating-system}
16816 declaration contains a list of G-expressions denoting the names of
16817 programs to be setuid-root (@pxref{Using the Configuration System}).
16818 For instance, the @command{passwd} program, which is part of the Shadow
16819 package, can be designated by this G-expression (@pxref{G-Expressions}):
16822 #~(string-append #$shadow "/bin/passwd")
16825 A default set of setuid programs is defined by the
16826 @code{%setuid-programs} variable of the @code{(gnu system)} module.
16828 @defvr {Scheme Variable} %setuid-programs
16829 A list of G-expressions denoting common programs that are setuid-root.
16831 The list includes commands such as @command{passwd}, @command{ping},
16832 @command{su}, and @command{sudo}.
16835 Under the hood, the actual setuid programs are created in the
16836 @file{/run/setuid-programs} directory at system activation time. The
16837 files in this directory refer to the ``real'' binaries, which are in the
16840 @node X.509 Certificates
16841 @subsection X.509 Certificates
16843 @cindex HTTPS, certificates
16844 @cindex X.509 certificates
16846 Web servers available over HTTPS (that is, HTTP over the transport-layer
16847 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
16848 that the client can then use to @emph{authenticate} the server. To do
16849 that, clients verify that the server's certificate is signed by a
16850 so-called @dfn{certificate authority} (CA). But to verify the CA's
16851 signature, clients must have first acquired the CA's certificate.
16853 Web browsers such as GNU@tie{}IceCat include their own set of CA
16854 certificates, such that they are able to verify CA signatures
16857 However, most other programs that can talk HTTPS---@command{wget},
16858 @command{git}, @command{w3m}, etc.---need to be told where CA
16859 certificates can be found.
16861 @cindex @code{nss-certs}
16862 In GuixSD, this is done by adding a package that provides certificates
16863 to the @code{packages} field of the @code{operating-system} declaration
16864 (@pxref{operating-system Reference}). GuixSD includes one such package,
16865 @code{nss-certs}, which is a set of CA certificates provided as part of
16866 Mozilla's Network Security Services.
16868 Note that it is @emph{not} part of @var{%base-packages}, so you need to
16869 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
16870 most applications and libraries look for certificates by default, points
16871 to the certificates installed globally.
16873 Unprivileged users, including users of Guix on a foreign distro,
16874 can also install their own certificate package in
16875 their profile. A number of environment variables need to be defined so
16876 that applications and libraries know where to find them. Namely, the
16877 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
16878 variables. Some applications add their own environment variables; for
16879 instance, the Git version control system honors the certificate bundle
16880 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
16881 would typically run something like:
16884 $ guix package -i nss-certs
16885 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
16886 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
16887 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
16890 As another example, R requires the @code{CURL_CA_BUNDLE} environment
16891 variable to point to a certificate bundle, so you would have to run
16892 something like this:
16895 $ guix package -i nss-certs
16896 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
16899 For other applications you may want to look up the required environment
16900 variable in the relevant documentation.
16903 @node Name Service Switch
16904 @subsection Name Service Switch
16906 @cindex name service switch
16908 The @code{(gnu system nss)} module provides bindings to the
16909 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
16910 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
16911 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
16912 extended with new ``name'' lookup methods for system databases, which
16913 includes host names, service names, user accounts, and more (@pxref{Name
16914 Service Switch, System Databases and Name Service Switch,, libc, The GNU
16915 C Library Reference Manual}).
16917 The NSS configuration specifies, for each system database, which lookup
16918 method is to be used, and how the various methods are chained
16919 together---for instance, under which circumstances NSS should try the
16920 next method in the list. The NSS configuration is given in the
16921 @code{name-service-switch} field of @code{operating-system} declarations
16922 (@pxref{operating-system Reference, @code{name-service-switch}}).
16925 @cindex .local, host name lookup
16926 As an example, the declaration below configures the NSS to use the
16927 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
16928 back-end}, which supports host name lookups over multicast DNS (mDNS)
16929 for host names ending in @code{.local}:
16932 (name-service-switch
16933 (hosts (list %files ;first, check /etc/hosts
16935 ;; If the above did not succeed, try
16936 ;; with 'mdns_minimal'.
16938 (name "mdns_minimal")
16940 ;; 'mdns_minimal' is authoritative for
16941 ;; '.local'. When it returns "not found",
16942 ;; no need to try the next methods.
16943 (reaction (lookup-specification
16944 (not-found => return))))
16946 ;; Then fall back to DNS.
16950 ;; Finally, try with the "full" 'mdns'.
16955 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
16956 contains this configuration, so you will not have to type it if all you
16957 want is to have @code{.local} host lookup working.
16959 Note that, in this case, in addition to setting the
16960 @code{name-service-switch} of the @code{operating-system} declaration,
16961 you also need to use @code{avahi-service} (@pxref{Networking Services,
16962 @code{avahi-service}}), or @var{%desktop-services}, which includes it
16963 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
16964 to the name service cache daemon (@pxref{Base Services,
16965 @code{nscd-service}}).
16967 For convenience, the following variables provide typical NSS
16970 @defvr {Scheme Variable} %default-nss
16971 This is the default name service switch configuration, a
16972 @code{name-service-switch} object.
16975 @defvr {Scheme Variable} %mdns-host-lookup-nss
16976 This is the name service switch configuration with support for host name
16977 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
16980 The reference for name service switch configuration is given below. It
16981 is a direct mapping of the configuration file format of the C library , so
16982 please refer to the C library manual for more information (@pxref{NSS
16983 Configuration File,,, libc, The GNU C Library Reference Manual}).
16984 Compared to the configuration file format of libc NSS, it has the advantage
16985 not only of adding this warm parenthetic feel that we like, but also
16986 static checks: you will know about syntax errors and typos as soon as you
16987 run @command{guix system}.
16989 @deftp {Data Type} name-service-switch
16991 This is the data type representation the configuration of libc's name
16992 service switch (NSS). Each field below represents one of the supported
17009 The system databases handled by the NSS. Each of these fields must be a
17010 list of @code{<name-service>} objects (see below).
17014 @deftp {Data Type} name-service
17016 This is the data type representing an actual name service and the
17017 associated lookup action.
17021 A string denoting the name service (@pxref{Services in the NSS
17022 configuration,,, libc, The GNU C Library Reference Manual}).
17024 Note that name services listed here must be visible to nscd. This is
17025 achieved by passing the @code{#:name-services} argument to
17026 @code{nscd-service} the list of packages providing the needed name
17027 services (@pxref{Base Services, @code{nscd-service}}).
17030 An action specified using the @code{lookup-specification} macro
17031 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
17032 Reference Manual}). For example:
17035 (lookup-specification (unavailable => continue)
17036 (success => return))
17041 @node Initial RAM Disk
17042 @subsection Initial RAM Disk
17045 @cindex initial RAM disk
17046 For bootstrapping purposes, the Linux-Libre kernel is passed an
17047 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
17048 root file system as well as an initialization script. The latter is
17049 responsible for mounting the real root file system, and for loading any
17050 kernel modules that may be needed to achieve that.
17052 The @code{initrd} field of an @code{operating-system} declaration allows
17053 you to specify which initrd you would like to use. The @code{(gnu
17054 system linux-initrd)} module provides three ways to build an initrd: the
17055 high-level @code{base-initrd} procedure and the low-level
17056 @code{raw-initrd} and @code{expression->initrd} procedures.
17058 The @code{base-initrd} procedure is intended to cover most common uses.
17059 For example, if you want to add a bunch of kernel modules to be loaded
17060 at boot time, you can define the @code{initrd} field of the operating
17061 system declaration like this:
17064 (initrd (lambda (file-systems . rest)
17065 ;; Create a standard initrd that has modules "foo.ko"
17066 ;; and "bar.ko", as well as their dependencies, in
17067 ;; addition to the modules available by default.
17068 (apply base-initrd file-systems
17069 #:extra-modules '("foo" "bar")
17073 The @code{base-initrd} procedure also handles common use cases that
17074 involves using the system as a QEMU guest, or as a ``live'' system with
17075 volatile root file system.
17077 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
17078 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
17079 such as trying to guess which kernel modules and packages should be included
17080 to the initrd. An example use of @code{raw-initrd} is when a user has
17081 a custom Linux kernel configuration and default kernel modules included by
17082 @code{base-initrd} are not available.
17084 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
17085 honors several options passed on the Linux kernel command line
17086 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
17087 @code{-append} option of QEMU), notably:
17090 @item --load=@var{boot}
17091 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
17092 program, once it has mounted the root file system.
17094 GuixSD uses this option to yield control to a boot program that runs the
17095 service activation programs and then spawns the GNU@tie{}Shepherd, the
17096 initialization system.
17098 @item --root=@var{root}
17099 Mount @var{root} as the root file system. @var{root} can be a
17100 device name like @code{/dev/sda1}, a partition label, or a partition
17103 @item --system=@var{system}
17104 Have @file{/run/booted-system} and @file{/run/current-system} point to
17107 @item modprobe.blacklist=@var{modules}@dots{}
17108 @cindex module, black-listing
17109 @cindex black list, of kernel modules
17110 Instruct the initial RAM disk as well as the @command{modprobe} command
17111 (from the kmod package) to refuse to load @var{modules}. @var{modules}
17112 must be a comma-separated list of module names---e.g.,
17113 @code{usbkbd,9pnet}.
17116 Start a read-eval-print loop (REPL) from the initial RAM disk before it
17117 tries to load kernel modules and to mount the root file system. Our
17118 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
17119 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
17120 Manual}, for more information on Guile's REPL.
17124 Now that you know all the features that initial RAM disks produced by
17125 @code{base-initrd} and @code{raw-initrd} provide,
17126 here is how to use it and customize it further.
17129 @cindex initial RAM disk
17130 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
17131 [#:linux-modules '()] [#:mapped-devices '()] @
17132 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
17133 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
17134 a list of file systems to be mounted by the initrd, possibly in addition to
17135 the root file system specified on the kernel command line via @code{--root}.
17136 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
17137 @var{mapped-devices} is a list of device mappings to realize before
17138 @var{file-systems} are mounted (@pxref{Mapped Devices}).
17139 @var{helper-packages} is a list of packages to be copied in the initrd. It may
17140 include @code{e2fsck/static} or other packages needed by the initrd to check
17143 When @var{qemu-networking?} is true, set up networking with the standard QEMU
17144 parameters. When @var{virtio?} is true, load additional modules so that the
17145 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
17147 When @var{volatile-root?} is true, the root file system is writable but any changes
17151 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
17152 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
17153 [#:virtio? #t] [#:extra-modules '()]
17154 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
17155 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
17156 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
17157 also behaves as in @code{raw-initrd}.
17159 When @var{virtio?} is true, load additional modules so that the
17160 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
17162 The initrd is automatically populated with all the kernel modules necessary
17163 for @var{file-systems} and for the given options. However, additional kernel
17164 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
17165 loaded at boot time in the order in which they appear.
17168 Needless to say, the initrds we produce and use embed a
17169 statically-linked Guile, and the initialization program is a Guile
17170 program. That gives a lot of flexibility. The
17171 @code{expression->initrd} procedure builds such an initrd, given the
17172 program to run in that initrd.
17174 @deffn {Monadic Procedure} expression->initrd @var{exp} @
17175 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
17176 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
17177 containing @var{guile} and that evaluates @var{exp}, a G-expression,
17178 upon booting. All the derivations referenced by @var{exp} are
17179 automatically copied to the initrd.
17182 @node Bootloader Configuration
17183 @subsection Bootloader Configuration
17186 @cindex boot loader
17188 The operating system supports multiple bootloaders. The bootloader is
17189 configured using @code{bootloader-configuration} declaration. All the
17190 fields of this structure are bootloader agnostic except for one field,
17191 @code{bootloader} that indicates the bootloader to be configured and
17194 Some of the bootloaders do not honor every field of
17195 @code{bootloader-configuration}. For instance, the extlinux
17196 bootloader does not support themes and thus ignores the @code{theme}
17199 @deftp {Data Type} bootloader-configuration
17200 The type of a bootloader configuration declaration.
17204 @item @code{bootloader}
17205 @cindex EFI, bootloader
17206 @cindex UEFI, bootloader
17207 @cindex BIOS, bootloader
17208 The bootloader to use, as a @code{bootloader} object. For now
17209 @code{grub-bootloader}, @code{grub-efi-bootloader},
17210 @code{extlinux-bootloader} and @code{u-boot-bootloader} are supported.
17211 @code{grub-efi-bootloader} allows to boot on modern systems using the
17212 @dfn{Unified Extensible Firmware Interface} (UEFI).
17214 Available bootloaders are described in @code{(gnu bootloader @dots{})}
17217 @item @code{target}
17218 This is a string denoting the target onto which to install the
17219 bootloader. The exact interpretation depends on the bootloader in
17220 question; for @code{grub-bootloader}, for example, it should be a device
17221 name understood by the bootloader @command{installer} command, such as
17222 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking
17223 grub-install,,, grub, GNU GRUB Manual}). For
17224 @code{grub-efi-bootloader}, it should be the path to a mounted EFI file
17227 @item @code{menu-entries} (default: @code{()})
17228 A possibly empty list of @code{menu-entry} objects (see below), denoting
17229 entries to appear in the bootloader menu, in addition to the current
17230 system entry and the entry pointing to previous system generations.
17233 @item @code{default-entry} (default: @code{0})
17234 The index of the default boot menu entry. Index 0 is for the entry of the
17237 @item @code{timeout} (default: @code{5})
17238 The number of seconds to wait for keyboard input before booting. Set to
17239 0 to boot immediately, and to -1 to wait indefinitely.
17241 @item @code{theme} (default: @var{#f})
17242 The bootloader theme object describing the theme to use. If no theme
17243 is provided, some bootloaders might use a default theme, that's true
17246 @item @code{terminal-outputs} (default: @code{'gfxterm})
17247 The output terminals used for the bootloader boot menu, as a list of
17248 symbols. GRUB accepts the values: @code{console}, @code{serial},
17249 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
17250 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
17251 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
17252 configuration,,, grub,GNU GRUB manual}).
17254 @item @code{terminal-inputs} (default: @code{'()})
17255 The input terminals used for the bootloader boot menu, as a list of
17256 symbols. For GRUB, the default is the native platform terminal as
17257 determined at run-time. GRUB accepts the values: @code{console},
17258 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
17259 @code{usb_keyboard}. This field corresponds to the GRUB variable
17260 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
17263 @item @code{serial-unit} (default: @code{#f})
17264 The serial unit used by the bootloader, as an integer from 0 to 3.
17265 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
17266 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
17268 @item @code{serial-speed} (default: @code{#f})
17269 The speed of the serial interface, as an integer. For GRUB, the
17270 default value is chosen at run-time; currently GRUB chooses
17271 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
17278 Should you want to list additional boot menu entries @i{via} the
17279 @code{menu-entries} field above, you will need to create them with the
17280 @code{menu-entry} form. For example, imagine you want to be able to
17281 boot another distro (hard to imagine!), you can define a menu entry
17286 (label "The Other Distro")
17287 (linux "/boot/old/vmlinux-2.6.32")
17288 (linux-arguments '("root=/dev/sda2"))
17289 (initrd "/boot/old/initrd"))
17294 @deftp {Data Type} menu-entry
17295 The type of an entry in the bootloader menu.
17300 The label to show in the menu---e.g., @code{"GNU"}.
17303 The Linux kernel image to boot, for example:
17306 (file-append linux-libre "/bzImage")
17309 For GRUB, it is also possible to specify a device explicitly in the
17310 file path using GRUB's device naming convention (@pxref{Naming
17311 convention,,, grub, GNU GRUB manual}), for example:
17314 "(hd0,msdos1)/boot/vmlinuz"
17317 If the device is specified explicitly as above, then the @code{device}
17318 field is ignored entirely.
17320 @item @code{linux-arguments} (default: @code{()})
17321 The list of extra Linux kernel command-line arguments---e.g.,
17322 @code{("console=ttyS0")}.
17324 @item @code{initrd}
17325 A G-Expression or string denoting the file name of the initial RAM disk
17326 to use (@pxref{G-Expressions}).
17327 @item @code{device} (default: @code{#f})
17328 The device where the kernel and initrd are to be found---i.e., for GRUB,
17329 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
17331 This may be a file system label (a string), a file system UUID (a
17332 bytevector, @pxref{File Systems}), or @code{#f}, in which case
17333 the bootloader will search the device containing the file specified by
17334 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
17335 must @emph{not} be an OS device name such as @file{/dev/sda1}.
17340 @c FIXME: Write documentation once it's stable.
17341 Fow now only GRUB has theme support. GRUB themes are created using
17342 the @code{grub-theme} form, which is not documented yet.
17344 @defvr {Scheme Variable} %default-theme
17345 This is the default GRUB theme used by the operating system if no
17346 @code{theme} field is specified in @code{bootloader-configuration}
17349 It comes with a fancy background image displaying the GNU and Guix
17354 @node Invoking guix system
17355 @subsection Invoking @code{guix system}
17357 Once you have written an operating system declaration as seen in the
17358 previous section, it can be @dfn{instantiated} using the @command{guix
17359 system} command. The synopsis is:
17362 guix system @var{options}@dots{} @var{action} @var{file}
17365 @var{file} must be the name of a file containing an
17366 @code{operating-system} declaration. @var{action} specifies how the
17367 operating system is instantiated. Currently the following values are
17372 Build the operating system described in @var{file}, activate it, and
17373 switch to it@footnote{This action (and the related actions
17374 @code{switch-generation} and @code{roll-back}) are usable only on
17375 systems already running GuixSD.}.
17377 This effects all the configuration specified in @var{file}: user
17378 accounts, system services, global package list, setuid programs, etc.
17379 The command starts system services specified in @var{file} that are not
17380 currently running; if a service is currently running, it does not
17381 attempt to upgrade it since this would not be possible without stopping it
17384 This command creates a new generation whose number is one greater than
17385 the current generation (as reported by @command{guix system
17386 list-generations}). If that generation already exists, it will be
17387 overwritten. This behavior mirrors that of @command{guix package}
17388 (@pxref{Invoking guix package}).
17390 It also adds a bootloader menu entry for the new OS configuration,
17391 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
17392 entries for older configurations to a submenu, allowing you to choose
17393 an older system generation at boot time should you need it.
17396 @c The paragraph below refers to the problem discussed at
17397 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
17398 It is highly recommended to run @command{guix pull} once before you run
17399 @command{guix system reconfigure} for the first time (@pxref{Invoking
17400 guix pull}). Failing to do that you would see an older version of Guix
17401 once @command{reconfigure} has completed.
17404 @item switch-generation
17405 @cindex generations
17406 Switch to an existing system generation. This action atomically
17407 switches the system profile to the specified system generation. It
17408 also rearranges the system's existing bootloader menu entries. It
17409 makes the menu entry for the specified system generation the default,
17410 and it moves the entries for the other generatiors to a submenu, if
17411 supported by the bootloader being used. The next time the system
17412 boots, it will use the specified system generation.
17414 The bootloader itself is not being reinstalled when using this
17415 command. Thus, the installed bootloader is used with an updated
17416 configuration file.
17418 The target generation can be specified explicitly by its generation
17419 number. For example, the following invocation would switch to system
17423 guix system switch-generation 7
17426 The target generation can also be specified relative to the current
17427 generation with the form @code{+N} or @code{-N}, where @code{+3} means
17428 ``3 generations ahead of the current generation,'' and @code{-1} means
17429 ``1 generation prior to the current generation.'' When specifying a
17430 negative value such as @code{-1}, you must precede it with @code{--} to
17431 prevent it from being parsed as an option. For example:
17434 guix system switch-generation -- -1
17437 Currently, the effect of invoking this action is @emph{only} to switch
17438 the system profile to an existing generation and rearrange the
17439 bootloader menu entries. To actually start using the target system
17440 generation, you must reboot after running this action. In the future,
17441 it will be updated to do the same things as @command{reconfigure},
17442 like activating and deactivating services.
17444 This action will fail if the specified generation does not exist.
17447 @cindex rolling back
17448 Switch to the preceding system generation. The next time the system
17449 boots, it will use the preceding system generation. This is the inverse
17450 of @command{reconfigure}, and it is exactly the same as invoking
17451 @command{switch-generation} with an argument of @code{-1}.
17453 Currently, as with @command{switch-generation}, you must reboot after
17454 running this action to actually start using the preceding system
17458 Build the derivation of the operating system, which includes all the
17459 configuration files and programs needed to boot and run the system.
17460 This action does not actually install anything.
17463 Populate the given directory with all the files necessary to run the
17464 operating system specified in @var{file}. This is useful for first-time
17465 installations of GuixSD. For instance:
17468 guix system init my-os-config.scm /mnt
17471 copies to @file{/mnt} all the store items required by the configuration
17472 specified in @file{my-os-config.scm}. This includes configuration
17473 files, packages, and so on. It also creates other essential files
17474 needed for the system to operate correctly---e.g., the @file{/etc},
17475 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
17477 This command also installs bootloader on the target specified in
17478 @file{my-os-config}, unless the @option{--no-bootloader} option was
17482 @cindex virtual machine
17484 @anchor{guix system vm}
17485 Build a virtual machine that contains the operating system declared in
17486 @var{file}, and return a script to run that virtual machine (VM).
17487 Arguments given to the script are passed to QEMU as in the example
17488 below, which enables networking and requests 1@tie{}GiB of RAM for the
17492 $ /gnu/store/@dots{}-run-vm.sh -m 1024 -net user
17495 The VM shares its store with the host system.
17497 Additional file systems can be shared between the host and the VM using
17498 the @code{--share} and @code{--expose} command-line options: the former
17499 specifies a directory to be shared with write access, while the latter
17500 provides read-only access to the shared directory.
17502 The example below creates a VM in which the user's home directory is
17503 accessible read-only, and where the @file{/exchange} directory is a
17504 read-write mapping of @file{$HOME/tmp} on the host:
17507 guix system vm my-config.scm \
17508 --expose=$HOME --share=$HOME/tmp=/exchange
17511 On GNU/Linux, the default is to boot directly to the kernel; this has
17512 the advantage of requiring only a very tiny root disk image since the
17513 store of the host can then be mounted.
17515 The @code{--full-boot} option forces a complete boot sequence, starting
17516 with the bootloader. This requires more disk space since a root image
17517 containing at least the kernel, initrd, and bootloader data files must
17518 be created. The @code{--image-size} option can be used to specify the
17523 Return a virtual machine or disk image of the operating system declared
17524 in @var{file} that stands alone. By default, @command{guix system}
17525 estimates the size of the image needed to store the system, but you can
17526 use the @option{--image-size} option to specify a value.
17528 You can specify the root file system type by using the
17529 @option{--file-system-type} option. It defaults to @code{ext4}.
17531 When using @code{vm-image}, the returned image is in qcow2 format, which
17532 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
17533 for more information on how to run the image in a virtual machine.
17535 When using @code{disk-image}, a raw disk image is produced; it can be
17536 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
17537 the device corresponding to a USB stick, one can copy the image to it
17538 using the following command:
17541 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
17545 Return a script to run the operating system declared in @var{file}
17546 within a container. Containers are a set of lightweight isolation
17547 mechanisms provided by the kernel Linux-libre. Containers are
17548 substantially less resource-demanding than full virtual machines since
17549 the kernel, shared objects, and other resources can be shared with the
17550 host system; this also means they provide thinner isolation.
17552 Currently, the script must be run as root in order to support more than
17553 a single user and group. The container shares its store with the host
17556 As with the @code{vm} action (@pxref{guix system vm}), additional file
17557 systems to be shared between the host and container can be specified
17558 using the @option{--share} and @option{--expose} options:
17561 guix system container my-config.scm \
17562 --expose=$HOME --share=$HOME/tmp=/exchange
17566 This option requires Linux-libre 3.19 or newer.
17571 @var{options} can contain any of the common build options (@pxref{Common
17572 Build Options}). In addition, @var{options} can contain one of the
17576 @item --system=@var{system}
17577 @itemx -s @var{system}
17578 Attempt to build for @var{system} instead of the host system type.
17579 This works as per @command{guix build} (@pxref{Invoking guix build}).
17583 Return the derivation file name of the given operating system without
17586 @item --file-system-type=@var{type}
17587 @itemx -t @var{type}
17588 For the @code{disk-image} action, create a file system of the given
17589 @var{type} on the image.
17591 When this option is omitted, @command{guix system} uses @code{ext4}.
17593 @cindex ISO-9660 format
17594 @cindex CD image format
17595 @cindex DVD image format
17596 @code{--file-system-type=iso9660} produces an ISO-9660 image, suitable
17597 for burning on CDs and DVDs.
17599 @item --image-size=@var{size}
17600 For the @code{vm-image} and @code{disk-image} actions, create an image
17601 of the given @var{size}. @var{size} may be a number of bytes, or it may
17602 include a unit as a suffix (@pxref{Block size, size specifications,,
17603 coreutils, GNU Coreutils}).
17605 When this option is omitted, @command{guix system} computes an estimate
17606 of the image size as a function of the size of the system declared in
17609 @item --root=@var{file}
17610 @itemx -r @var{file}
17611 Make @var{file} a symlink to the result, and register it as a garbage
17614 @item --on-error=@var{strategy}
17615 Apply @var{strategy} when an error occurs when reading @var{file}.
17616 @var{strategy} may be one of the following:
17619 @item nothing-special
17620 Report the error concisely and exit. This is the default strategy.
17623 Likewise, but also display a backtrace.
17626 Report the error and enter Guile's debugger. From there, you can run
17627 commands such as @code{,bt} to get a backtrace, @code{,locals} to
17628 display local variable values, and more generally inspect the state of the
17629 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
17630 a list of available debugging commands.
17635 All the actions above, except @code{build} and @code{init},
17636 can use KVM support in the Linux-libre kernel. Specifically, if the
17637 machine has hardware virtualization support, the corresponding
17638 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
17639 must exist and be readable and writable by the user and by the
17640 build users of the daemon (@pxref{Build Environment Setup}).
17643 Once you have built, configured, re-configured, and re-re-configured
17644 your GuixSD installation, you may find it useful to list the operating
17645 system generations available on disk---and that you can choose from the
17646 bootloader boot menu:
17650 @item list-generations
17651 List a summary of each generation of the operating system available on
17652 disk, in a human-readable way. This is similar to the
17653 @option{--list-generations} option of @command{guix package}
17654 (@pxref{Invoking guix package}).
17656 Optionally, one can specify a pattern, with the same syntax that is used
17657 in @command{guix package --list-generations}, to restrict the list of
17658 generations displayed. For instance, the following command displays
17659 generations that are up to 10 days old:
17662 $ guix system list-generations 10d
17667 The @command{guix system} command has even more to offer! The following
17668 sub-commands allow you to visualize how your system services relate to
17671 @anchor{system-extension-graph}
17674 @item extension-graph
17675 Emit in Dot/Graphviz format to standard output the @dfn{service
17676 extension graph} of the operating system defined in @var{file}
17677 (@pxref{Service Composition}, for more information on service
17683 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
17686 produces a PDF file showing the extension relations among services.
17688 @anchor{system-shepherd-graph}
17689 @item shepherd-graph
17690 Emit in Dot/Graphviz format to standard output the @dfn{dependency
17691 graph} of shepherd services of the operating system defined in
17692 @var{file}. @xref{Shepherd Services}, for more information and for an
17697 @node Running GuixSD in a VM
17698 @subsection Running GuixSD in a Virtual Machine
17700 @cindex virtual machine
17701 To run GuixSD in a virtual machine (VM), one can either use the
17702 pre-built GuixSD VM image distributed at
17703 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
17704 , or build their own virtual machine image using @command{guix system
17705 vm-image} (@pxref{Invoking guix system}). The returned image is in
17706 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
17710 If you built your own image, you must copy it out of the store
17711 (@pxref{The Store}) and give yourself permission to write to the copy
17712 before you can use it. When invoking QEMU, you must choose a system
17713 emulator that is suitable for your hardware platform. Here is a minimal
17714 QEMU invocation that will boot the result of @command{guix system
17715 vm-image} on x86_64 hardware:
17718 $ qemu-system-x86_64 \
17719 -net user -net nic,model=virtio \
17720 -enable-kvm -m 256 /tmp/qemu-image
17723 Here is what each of these options means:
17726 @item qemu-system-x86_64
17727 This specifies the hardware platform to emulate. This should match the
17731 Enable the unprivileged user-mode network stack. The guest OS can
17732 access the host but not vice versa. This is the simplest way to get the
17735 @item -net nic,model=virtio
17736 You must create a network interface of a given model. If you do not
17737 create a NIC, the boot will fail. Assuming your hardware platform is
17738 x86_64, you can get a list of available NIC models by running
17739 @command{qemu-system-x86_64 -net nic,model=help}.
17742 If your system has hardware virtualization extensions, enabling the
17743 virtual machine support (KVM) of the Linux kernel will make things run
17747 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
17748 which may be insufficient for some operations.
17750 @item /tmp/qemu-image
17751 The file name of the qcow2 image.
17754 The default @command{run-vm.sh} script that is returned by an invocation of
17755 @command{guix system vm} does not add a @command{-net user} flag by default.
17756 To get network access from within the vm add the @code{(dhcp-client-service)}
17757 to your system definition and start the VM using
17758 @command{`guix system vm config.scm` -net user}. An important caveat of using
17759 @command{-net user} for networking is that @command{ping} will not work, because
17760 it uses the ICMP protocol. You'll have to use a different command to check for
17761 network connectivity, for example @command{guix download}.
17763 @subsubsection Connecting Through SSH
17767 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
17768 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
17769 boot unsupervised. It requires you to type some characters to initialize the
17770 randomness generator. In addition you need to forward the SSH port, 22 by
17771 default, to the host. You can do this with
17774 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
17777 To connect to the VM you can run
17780 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
17783 The @command{-p} tells @command{ssh} the port you want to connect to.
17784 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
17785 every time you modify your @command{config.scm} file and the
17786 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
17787 connection to an unknown host every time you connect.
17789 @subsubsection Using @command{virt-viewer} with Spice
17791 As an alternative to the default @command{qemu} graphical client you can
17792 use the @command{remote-viewer} from the @command{virt-viewer} package. To
17793 connect pass the @command{-spice port=5930,disable-ticketing} flag to
17794 @command{qemu}. See previous section for further information on how to do this.
17796 Spice also allows you to do some nice stuff like share your clipboard with your
17797 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
17800 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
17801 -chardev spicevmc,name=vdagent,id=vdagent
17802 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
17803 name=com.redhat.spice.0
17806 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
17808 @node Defining Services
17809 @subsection Defining Services
17811 The previous sections show the available services and how one can combine
17812 them in an @code{operating-system} declaration. But how do we define
17813 them in the first place? And what is a service anyway?
17816 * Service Composition:: The model for composing services.
17817 * Service Types and Services:: Types and services.
17818 * Service Reference:: API reference.
17819 * Shepherd Services:: A particular type of service.
17822 @node Service Composition
17823 @subsubsection Service Composition
17827 Here we define a @dfn{service} as, broadly, something that extends the
17828 functionality of the operating system. Often a service is a process---a
17829 @dfn{daemon}---started when the system boots: a secure shell server, a
17830 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
17831 whose execution can be triggered by another daemon---e.g., an FTP server
17832 started by @command{inetd} or a D-Bus service activated by
17833 @command{dbus-daemon}. Occasionally, a service does not map to a
17834 daemon. For instance, the ``account'' service collects user accounts
17835 and makes sure they exist when the system runs; the ``udev'' service
17836 collects device management rules and makes them available to the eudev
17837 daemon; the @file{/etc} service populates the @file{/etc} directory
17840 @cindex service extensions
17841 GuixSD services are connected by @dfn{extensions}. For instance, the
17842 secure shell service @emph{extends} the Shepherd---the GuixSD
17843 initialization system, running as PID@tie{}1---by giving it the command
17844 lines to start and stop the secure shell daemon (@pxref{Networking
17845 Services, @code{lsh-service}}); the UPower service extends the D-Bus
17846 service by passing it its @file{.service} specification, and extends the
17847 udev service by passing it device management rules (@pxref{Desktop
17848 Services, @code{upower-service}}); the Guix daemon service extends the
17849 Shepherd by passing it the command lines to start and stop the daemon,
17850 and extends the account service by passing it a list of required build
17851 user accounts (@pxref{Base Services}).
17853 All in all, services and their ``extends'' relations form a directed
17854 acyclic graph (DAG). If we represent services as boxes and extensions
17855 as arrows, a typical system might provide something like this:
17857 @image{images/service-graph,,5in,Typical service extension graph.}
17859 @cindex system service
17860 At the bottom, we see the @dfn{system service}, which produces the
17861 directory containing everything to run and boot the system, as returned
17862 by the @command{guix system build} command. @xref{Service Reference},
17863 to learn about the other service types shown here.
17864 @xref{system-extension-graph, the @command{guix system extension-graph}
17865 command}, for information on how to generate this representation for a
17866 particular operating system definition.
17868 @cindex service types
17869 Technically, developers can define @dfn{service types} to express these
17870 relations. There can be any number of services of a given type on the
17871 system---for instance, a system running two instances of the GNU secure
17872 shell server (lsh) has two instances of @var{lsh-service-type}, with
17873 different parameters.
17875 The following section describes the programming interface for service
17876 types and services.
17878 @node Service Types and Services
17879 @subsubsection Service Types and Services
17881 A @dfn{service type} is a node in the DAG described above. Let us start
17882 with a simple example, the service type for the Guix build daemon
17883 (@pxref{Invoking guix-daemon}):
17886 (define guix-service-type
17890 (list (service-extension shepherd-root-service-type guix-shepherd-service)
17891 (service-extension account-service-type guix-accounts)
17892 (service-extension activation-service-type guix-activation)))
17893 (default-value (guix-configuration))))
17897 It defines three things:
17901 A name, whose sole purpose is to make inspection and debugging easier.
17904 A list of @dfn{service extensions}, where each extension designates the
17905 target service type and a procedure that, given the parameters of the
17906 service, returns a list of objects to extend the service of that type.
17908 Every service type has at least one service extension. The only
17909 exception is the @dfn{boot service type}, which is the ultimate service.
17912 Optionally, a default value for instances of this type.
17915 In this example, @var{guix-service-type} extends three services:
17918 @item shepherd-root-service-type
17919 The @var{guix-shepherd-service} procedure defines how the Shepherd
17920 service is extended. Namely, it returns a @code{<shepherd-service>}
17921 object that defines how @command{guix-daemon} is started and stopped
17922 (@pxref{Shepherd Services}).
17924 @item account-service-type
17925 This extension for this service is computed by @var{guix-accounts},
17926 which returns a list of @code{user-group} and @code{user-account}
17927 objects representing the build user accounts (@pxref{Invoking
17930 @item activation-service-type
17931 Here @var{guix-activation} is a procedure that returns a gexp, which is
17932 a code snippet to run at ``activation time''---e.g., when the service is
17936 A service of this type is instantiated like this:
17939 (service guix-service-type
17940 (guix-configuration
17942 (use-substitutes? #f)))
17945 The second argument to the @code{service} form is a value representing
17946 the parameters of this specific service instance.
17947 @xref{guix-configuration-type, @code{guix-configuration}}, for
17948 information about the @code{guix-configuration} data type. When the
17949 value is omitted, the default value specified by
17950 @code{guix-service-type} is used:
17953 (service guix-service-type)
17956 @var{guix-service-type} is quite simple because it extends other
17957 services but is not extensible itself.
17959 @c @subsubsubsection Extensible Service Types
17961 The service type for an @emph{extensible} service looks like this:
17964 (define udev-service-type
17965 (service-type (name 'udev)
17967 (list (service-extension shepherd-root-service-type
17968 udev-shepherd-service)))
17970 (compose concatenate) ;concatenate the list of rules
17971 (extend (lambda (config rules)
17973 (($ <udev-configuration> udev initial-rules)
17974 (udev-configuration
17975 (udev udev) ;the udev package to use
17976 (rules (append initial-rules rules)))))))))
17979 This is the service type for the
17980 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
17981 management daemon}. Compared to the previous example, in addition to an
17982 extension of @var{shepherd-root-service-type}, we see two new fields:
17986 This is the procedure to @dfn{compose} the list of extensions to
17987 services of this type.
17989 Services can extend the udev service by passing it lists of rules; we
17990 compose those extensions simply by concatenating them.
17993 This procedure defines how the value of the service is @dfn{extended} with
17994 the composition of the extensions.
17996 Udev extensions are composed into a list of rules, but the udev service
17997 value is itself a @code{<udev-configuration>} record. So here, we
17998 extend that record by appending the list of rules it contains to the
17999 list of contributed rules.
18002 There can be only one instance of an extensible service type such as
18003 @var{udev-service-type}. If there were more, the
18004 @code{service-extension} specifications would be ambiguous.
18006 Still here? The next section provides a reference of the programming
18007 interface for services.
18009 @node Service Reference
18010 @subsubsection Service Reference
18012 We have seen an overview of service types (@pxref{Service Types and
18013 Services}). This section provides a reference on how to manipulate
18014 services and service types. This interface is provided by the
18015 @code{(gnu services)} module.
18017 @deffn {Scheme Procedure} service @var{type} [@var{value}]
18018 Return a new service of @var{type}, a @code{<service-type>} object (see
18019 below.) @var{value} can be any object; it represents the parameters of
18020 this particular service instance.
18022 When @var{value} is omitted, the default value specified by @var{type}
18023 is used; if @var{type} does not specify a default value, an error is
18026 For instance, this:
18029 (service openssh-service-type)
18033 is equivalent to this:
18036 (service openssh-service-type
18037 (openssh-configuration))
18040 In both cases the result is an instance of @code{openssh-service-type}
18041 with the default configuration.
18044 @deffn {Scheme Procedure} service? @var{obj}
18045 Return true if @var{obj} is a service.
18048 @deffn {Scheme Procedure} service-kind @var{service}
18049 Return the type of @var{service}---i.e., a @code{<service-type>} object.
18052 @deffn {Scheme Procedure} service-value @var{service}
18053 Return the value associated with @var{service}. It represents its
18057 Here is an example of how a service is created and manipulated:
18061 (service nginx-service-type
18062 (nginx-configuration
18064 (log-directory log-directory)
18065 (run-directory run-directory)
18066 (file config-file))))
18071 (eq? (service-kind s) nginx-service-type)
18075 The @code{modify-services} form provides a handy way to change the
18076 parameters of some of the services of a list such as
18077 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
18078 evaluates to a list of services. Of course, you could always use
18079 standard list combinators such as @code{map} and @code{fold} to do that
18080 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
18081 @code{modify-services} simply provides a more concise form for this
18084 @deffn {Scheme Syntax} modify-services @var{services} @
18085 (@var{type} @var{variable} => @var{body}) @dots{}
18087 Modify the services listed in @var{services} according to the given
18088 clauses. Each clause has the form:
18091 (@var{type} @var{variable} => @var{body})
18094 where @var{type} is a service type---e.g.,
18095 @code{guix-service-type}---and @var{variable} is an identifier that is
18096 bound within the @var{body} to the service parameters---e.g., a
18097 @code{guix-configuration} instance---of the original service of that
18100 The @var{body} should evaluate to the new service parameters, which will
18101 be used to configure the new service. This new service will replace the
18102 original in the resulting list. Because a service's service parameters
18103 are created using @code{define-record-type*}, you can write a succinct
18104 @var{body} that evaluates to the new service parameters by using the
18105 @code{inherit} feature that @code{define-record-type*} provides.
18107 @xref{Using the Configuration System}, for example usage.
18111 Next comes the programming interface for service types. This is
18112 something you want to know when writing new service definitions, but not
18113 necessarily when simply looking for ways to customize your
18114 @code{operating-system} declaration.
18116 @deftp {Data Type} service-type
18117 @cindex service type
18118 This is the representation of a @dfn{service type} (@pxref{Service Types
18123 This is a symbol, used only to simplify inspection and debugging.
18125 @item @code{extensions}
18126 A non-empty list of @code{<service-extension>} objects (see below).
18128 @item @code{compose} (default: @code{#f})
18129 If this is @code{#f}, then the service type denotes services that cannot
18130 be extended---i.e., services that do not receive ``values'' from other
18133 Otherwise, it must be a one-argument procedure. The procedure is called
18134 by @code{fold-services} and is passed a list of values collected from
18135 extensions. It must return a value that is a valid parameter value for
18136 the service instance.
18138 @item @code{extend} (default: @code{#f})
18139 If this is @code{#f}, services of this type cannot be extended.
18141 Otherwise, it must be a two-argument procedure: @code{fold-services}
18142 calls it, passing it the initial value of the service as the first argument
18143 and the result of applying @code{compose} to the extension values as the
18147 @xref{Service Types and Services}, for examples.
18150 @deffn {Scheme Procedure} service-extension @var{target-type} @
18152 Return a new extension for services of type @var{target-type}.
18153 @var{compute} must be a one-argument procedure: @code{fold-services}
18154 calls it, passing it the value associated with the service that provides
18155 the extension; it must return a valid value for the target service.
18158 @deffn {Scheme Procedure} service-extension? @var{obj}
18159 Return true if @var{obj} is a service extension.
18162 Occasionally, you might want to simply extend an existing service. This
18163 involves creating a new service type and specifying the extension of
18164 interest, which can be verbose; the @code{simple-service} procedure
18165 provides a shorthand for this.
18167 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
18168 Return a service that extends @var{target} with @var{value}. This works
18169 by creating a singleton service type @var{name}, of which the returned
18170 service is an instance.
18172 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
18176 (simple-service 'my-mcron-job mcron-service-type
18177 #~(job '(next-hour (3)) "guix gc -F 2G"))
18181 At the core of the service abstraction lies the @code{fold-services}
18182 procedure, which is responsible for ``compiling'' a list of services
18183 down to a single directory that contains everything needed to boot and
18184 run the system---the directory shown by the @command{guix system build}
18185 command (@pxref{Invoking guix system}). In essence, it propagates
18186 service extensions down the service graph, updating each node parameters
18187 on the way, until it reaches the root node.
18189 @deffn {Scheme Procedure} fold-services @var{services} @
18190 [#:target-type @var{system-service-type}]
18191 Fold @var{services} by propagating their extensions down to the root of
18192 type @var{target-type}; return the root service adjusted accordingly.
18195 Lastly, the @code{(gnu services)} module also defines several essential
18196 service types, some of which are listed below.
18198 @defvr {Scheme Variable} system-service-type
18199 This is the root of the service graph. It produces the system directory
18200 as returned by the @command{guix system build} command.
18203 @defvr {Scheme Variable} boot-service-type
18204 The type of the ``boot service'', which produces the @dfn{boot script}.
18205 The boot script is what the initial RAM disk runs when booting.
18208 @defvr {Scheme Variable} etc-service-type
18209 The type of the @file{/etc} service. This service can be extended by
18210 passing it name/file tuples such as:
18213 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
18216 In this example, the effect would be to add an @file{/etc/issue} file
18217 pointing to the given file.
18220 @defvr {Scheme Variable} setuid-program-service-type
18221 Type for the ``setuid-program service''. This service collects lists of
18222 executable file names, passed as gexps, and adds them to the set of
18223 setuid-root programs on the system (@pxref{Setuid Programs}).
18226 @defvr {Scheme Variable} profile-service-type
18227 Type of the service that populates the @dfn{system profile}---i.e., the
18228 programs under @file{/run/current-system/profile}. Other services can
18229 extend it by passing it lists of packages to add to the system profile.
18233 @node Shepherd Services
18234 @subsubsection Shepherd Services
18236 @cindex shepherd services
18238 @cindex init system
18239 The @code{(gnu services shepherd)} module provides a way to define
18240 services managed by the GNU@tie{}Shepherd, which is the GuixSD
18241 initialization system---the first process that is started when the
18242 system boots, also known as PID@tie{}1
18243 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
18245 Services in the Shepherd can depend on each other. For instance, the
18246 SSH daemon may need to be started after the syslog daemon has been
18247 started, which in turn can only happen once all the file systems have
18248 been mounted. The simple operating system defined earlier (@pxref{Using
18249 the Configuration System}) results in a service graph like this:
18251 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
18253 You can actually generate such a graph for any operating system
18254 definition using the @command{guix system shepherd-graph} command
18255 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
18257 The @var{%shepherd-root-service} is a service object representing
18258 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
18259 by passing it lists of @code{<shepherd-service>} objects.
18261 @deftp {Data Type} shepherd-service
18262 The data type representing a service managed by the Shepherd.
18265 @item @code{provision}
18266 This is a list of symbols denoting what the service provides.
18268 These are the names that may be passed to @command{herd start},
18269 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
18270 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
18271 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
18273 @item @code{requirements} (default: @code{'()})
18274 List of symbols denoting the Shepherd services this one depends on.
18276 @item @code{respawn?} (default: @code{#t})
18277 Whether to restart the service when it stops, for instance when the
18278 underlying process dies.
18281 @itemx @code{stop} (default: @code{#~(const #f)})
18282 The @code{start} and @code{stop} fields refer to the Shepherd's
18283 facilities to start and stop processes (@pxref{Service De- and
18284 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
18285 G-expressions that get expanded in the Shepherd configuration file
18286 (@pxref{G-Expressions}).
18288 @item @code{documentation}
18289 A documentation string, as shown when running:
18292 herd doc @var{service-name}
18295 where @var{service-name} is one of the symbols in @var{provision}
18296 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
18298 @item @code{modules} (default: @var{%default-modules})
18299 This is the list of modules that must be in scope when @code{start} and
18300 @code{stop} are evaluated.
18305 @defvr {Scheme Variable} shepherd-root-service-type
18306 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
18308 This is the service type that extensions target when they want to create
18309 shepherd services (@pxref{Service Types and Services}, for an example).
18310 Each extension must pass a list of @code{<shepherd-service>}.
18313 @defvr {Scheme Variable} %shepherd-root-service
18314 This service represents PID@tie{}1.
18318 @node Documentation
18319 @section Documentation
18321 @cindex documentation, searching for
18322 @cindex searching for documentation
18323 @cindex Info, documentation format
18325 @cindex manual pages
18326 In most cases packages installed with Guix come with documentation.
18327 There are two main documentation formats: ``Info'', a browseable
18328 hypertext format used for GNU software, and ``manual pages'' (or ``man
18329 pages''), the linear documentation format traditionally found on Unix.
18330 Info manuals are accessed with the @command{info} command or with Emacs,
18331 and man pages are accessed using @command{man}.
18333 You can look for documentation of software installed on your system by
18334 keyword. For example, the following command searches for information
18335 about ``TLS'' in Info manuals:
18339 "(emacs)Network Security" -- STARTTLS
18340 "(emacs)Network Security" -- TLS
18341 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
18342 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
18347 The command below searches for the same keyword in man pages:
18351 SSL (7) - OpenSSL SSL/TLS library
18352 certtool (1) - GnuTLS certificate tool
18356 These searches are purely local to your computer so you have the
18357 guarantee that documentation you find corresponds to what you have
18358 actually installed, you can access it off-line, and your privacy is
18361 Once you have these results, you can view the relevant documentation by
18365 $ info "(gnutls)Core TLS API"
18375 Info manuals contain sections and indices as well as hyperlinks like
18376 those found in Web pages. The @command{info} reader (@pxref{Top, Info
18377 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
18378 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
18379 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
18380 Introduction}, for an introduction to Info navigation.
18382 @node Installing Debugging Files
18383 @section Installing Debugging Files
18385 @cindex debugging files
18386 Program binaries, as produced by the GCC compilers for instance, are
18387 typically written in the ELF format, with a section containing
18388 @dfn{debugging information}. Debugging information is what allows the
18389 debugger, GDB, to map binary code to source code; it is required to
18390 debug a compiled program in good conditions.
18392 The problem with debugging information is that is takes up a fair amount
18393 of disk space. For example, debugging information for the GNU C Library
18394 weighs in at more than 60 MiB. Thus, as a user, keeping all the
18395 debugging info of all the installed programs is usually not an option.
18396 Yet, space savings should not come at the cost of an impediment to
18397 debugging---especially in the GNU system, which should make it easier
18398 for users to exert their computing freedom (@pxref{GNU Distribution}).
18400 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
18401 mechanism that allows users to get the best of both worlds: debugging
18402 information can be stripped from the binaries and stored in separate
18403 files. GDB is then able to load debugging information from those files,
18404 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
18407 The GNU distribution takes advantage of this by storing debugging
18408 information in the @code{lib/debug} sub-directory of a separate package
18409 output unimaginatively called @code{debug} (@pxref{Packages with
18410 Multiple Outputs}). Users can choose to install the @code{debug} output
18411 of a package when they need it. For instance, the following command
18412 installs the debugging information for the GNU C Library and for GNU
18416 guix package -i glibc:debug guile:debug
18419 GDB must then be told to look for debug files in the user's profile, by
18420 setting the @code{debug-file-directory} variable (consider setting it
18421 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
18425 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
18428 From there on, GDB will pick up debugging information from the
18429 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
18431 In addition, you will most likely want GDB to be able to show the source
18432 code being debugged. To do that, you will have to unpack the source
18433 code of the package of interest (obtained with @code{guix build
18434 --source}, @pxref{Invoking guix build}), and to point GDB to that source
18435 directory using the @code{directory} command (@pxref{Source Path,
18436 @code{directory},, gdb, Debugging with GDB}).
18438 @c XXX: keep me up-to-date
18439 The @code{debug} output mechanism in Guix is implemented by the
18440 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
18441 opt-in---debugging information is available only for the packages
18442 with definitions explicitly declaring a @code{debug} output. This may be
18443 changed to opt-out in the future if our build farm servers can handle
18444 the load. To check whether a package has a @code{debug} output, use
18445 @command{guix package --list-available} (@pxref{Invoking guix package}).
18448 @node Security Updates
18449 @section Security Updates
18451 @cindex security updates
18452 @cindex security vulnerabilities
18453 Occasionally, important security vulnerabilities are discovered in software
18454 packages and must be patched. Guix developers try hard to keep track of
18455 known vulnerabilities and to apply fixes as soon as possible in the
18456 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
18457 containing only security updates.) The @command{guix lint} tool helps
18458 developers find out about vulnerable versions of software packages in the
18463 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
18464 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
18465 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
18469 @xref{Invoking guix lint}, for more information.
18472 As of version @value{VERSION}, the feature described below is considered
18476 Guix follows a functional
18477 package management discipline (@pxref{Introduction}), which implies
18478 that, when a package is changed, @emph{every package that depends on it}
18479 must be rebuilt. This can significantly slow down the deployment of
18480 fixes in core packages such as libc or Bash, since basically the whole
18481 distribution would need to be rebuilt. Using pre-built binaries helps
18482 (@pxref{Substitutes}), but deployment may still take more time than
18486 To address this, Guix implements @dfn{grafts}, a mechanism that allows
18487 for fast deployment of critical updates without the costs associated
18488 with a whole-distribution rebuild. The idea is to rebuild only the
18489 package that needs to be patched, and then to ``graft'' it onto packages
18490 explicitly installed by the user and that were previously referring to
18491 the original package. The cost of grafting is typically very low, and
18492 order of magnitudes lower than a full rebuild of the dependency chain.
18494 @cindex replacements of packages, for grafts
18495 For instance, suppose a security update needs to be applied to Bash.
18496 Guix developers will provide a package definition for the ``fixed''
18497 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
18498 Packages}). Then, the original package definition is augmented with a
18499 @code{replacement} field pointing to the package containing the bug fix:
18506 (replacement bash-fixed)))
18509 From there on, any package depending directly or indirectly on Bash---as
18510 reported by @command{guix gc --requisites} (@pxref{Invoking guix
18511 gc})---that is installed is automatically ``rewritten'' to refer to
18512 @var{bash-fixed} instead of @var{bash}. This grafting process takes
18513 time proportional to the size of the package, usually less than a
18514 minute for an ``average'' package on a recent machine. Grafting is
18515 recursive: when an indirect dependency requires grafting, then grafting
18516 ``propagates'' up to the package that the user is installing.
18518 Currently, the length of the name and version of the graft and that of
18519 the package it replaces (@var{bash-fixed} and @var{bash} in the example
18520 above) must be equal. This restriction mostly comes from the fact that
18521 grafting works by patching files, including binary files, directly.
18522 Other restrictions may apply: for instance, when adding a graft to a
18523 package providing a shared library, the original shared library and its
18524 replacement must have the same @code{SONAME} and be binary-compatible.
18526 The @option{--no-grafts} command-line option allows you to forcefully
18527 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
18531 guix build bash --no-grafts
18535 returns the store file name of the original Bash, whereas:
18542 returns the store file name of the ``fixed'', replacement Bash. This
18543 allows you to distinguish between the two variants of Bash.
18545 To verify which Bash your whole profile refers to, you can run
18546 (@pxref{Invoking guix gc}):
18549 guix gc -R `readlink -f ~/.guix-profile` | grep bash
18553 @dots{} and compare the store file names that you get with those above.
18554 Likewise for a complete GuixSD system generation:
18557 guix gc -R `guix system build my-config.scm` | grep bash
18560 Lastly, to check which Bash running processes are using, you can use the
18561 @command{lsof} command:
18564 lsof | grep /gnu/store/.*bash
18568 @node Package Modules
18569 @section Package Modules
18571 From a programming viewpoint, the package definitions of the
18572 GNU distribution are provided by Guile modules in the @code{(gnu packages
18573 @dots{})} name space@footnote{Note that packages under the @code{(gnu
18574 packages @dots{})} module name space are not necessarily ``GNU
18575 packages''. This module naming scheme follows the usual Guile module
18576 naming convention: @code{gnu} means that these modules are distributed
18577 as part of the GNU system, and @code{packages} identifies modules that
18578 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
18579 Reference Manual}). For instance, the @code{(gnu packages emacs)}
18580 module exports a variable named @code{emacs}, which is bound to a
18581 @code{<package>} object (@pxref{Defining Packages}).
18583 The @code{(gnu packages @dots{})} module name space is
18584 automatically scanned for packages by the command-line tools. For
18585 instance, when running @code{guix package -i emacs}, all the @code{(gnu
18586 packages @dots{})} modules are scanned until one that exports a package
18587 object whose name is @code{emacs} is found. This package search
18588 facility is implemented in the @code{(gnu packages)} module.
18590 @cindex customization, of packages
18591 @cindex package module search path
18592 Users can store package definitions in modules with different
18593 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
18594 name and module name must match. For instance, the @code{(my-packages
18595 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
18596 relative to the load path specified with @option{--load-path} or
18597 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
18598 guile, GNU Guile Reference Manual}, for details.}. These package definitions
18599 will not be visible by default. Users can invoke commands such as
18600 @command{guix package} and @command{guix build} with the
18601 @code{-e} option so that they know where to find the package. Better
18602 yet, they can use the
18603 @code{-L} option of these commands to make those modules visible
18604 (@pxref{Invoking guix build, @code{--load-path}}), or define the
18605 @code{GUIX_PACKAGE_PATH} environment variable. This environment
18606 variable makes it easy to extend or customize the distribution and is
18607 honored by all the user interfaces.
18609 @defvr {Environment Variable} GUIX_PACKAGE_PATH
18610 This is a colon-separated list of directories to search for additional
18611 package modules. Directories listed in this variable take precedence
18612 over the own modules of the distribution.
18615 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
18616 each package is built based solely on other packages in the
18617 distribution. The root of this dependency graph is a small set of
18618 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
18619 bootstrap)} module. For more information on bootstrapping,
18620 @pxref{Bootstrapping}.
18622 @node Packaging Guidelines
18623 @section Packaging Guidelines
18625 @cindex packages, creating
18626 The GNU distribution is nascent and may well lack some of your favorite
18627 packages. This section describes how you can help make the distribution
18628 grow. @xref{Contributing}, for additional information on how you can
18631 Free software packages are usually distributed in the form of
18632 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
18633 all the source files. Adding a package to the distribution means
18634 essentially two things: adding a @dfn{recipe} that describes how to
18635 build the package, including a list of other packages required to build
18636 it, and adding @dfn{package metadata} along with that recipe, such as a
18637 description and licensing information.
18639 In Guix all this information is embodied in @dfn{package definitions}.
18640 Package definitions provide a high-level view of the package. They are
18641 written using the syntax of the Scheme programming language; in fact,
18642 for each package we define a variable bound to the package definition,
18643 and export that variable from a module (@pxref{Package Modules}).
18644 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
18645 creating packages. For more information on package definitions,
18646 @pxref{Defining Packages}.
18648 Once a package definition is in place, stored in a file in the Guix
18649 source tree, it can be tested using the @command{guix build} command
18650 (@pxref{Invoking guix build}). For example, assuming the new package is
18651 called @code{gnew}, you may run this command from the Guix build tree
18652 (@pxref{Running Guix Before It Is Installed}):
18655 ./pre-inst-env guix build gnew --keep-failed
18658 Using @code{--keep-failed} makes it easier to debug build failures since
18659 it provides access to the failed build tree. Another useful
18660 command-line option when debugging is @code{--log-file}, to access the
18663 If the package is unknown to the @command{guix} command, it may be that
18664 the source file contains a syntax error, or lacks a @code{define-public}
18665 clause to export the package variable. To figure it out, you may load
18666 the module from Guile to get more information about the actual error:
18669 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
18672 Once your package builds correctly, please send us a patch
18673 (@pxref{Contributing}). Well, if you need help, we will be happy to
18674 help you too. Once the patch is committed in the Guix repository, the
18675 new package automatically gets built on the supported platforms by
18676 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
18679 @cindex substituter
18680 Users can obtain the new package definition simply by running
18681 @command{guix pull} (@pxref{Invoking guix pull}). When
18682 @code{hydra.gnu.org} is done building the package, installing the
18683 package automatically downloads binaries from there
18684 (@pxref{Substitutes}). The only place where human intervention is
18685 needed is to review and apply the patch.
18689 * Software Freedom:: What may go into the distribution.
18690 * Package Naming:: What's in a name?
18691 * Version Numbers:: When the name is not enough.
18692 * Synopses and Descriptions:: Helping users find the right package.
18693 * Python Modules:: A touch of British comedy.
18694 * Perl Modules:: Little pearls.
18695 * Java Packages:: Coffee break.
18696 * Fonts:: Fond of fonts.
18699 @node Software Freedom
18700 @subsection Software Freedom
18702 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
18703 @cindex free software
18704 The GNU operating system has been developed so that users can have
18705 freedom in their computing. GNU is @dfn{free software}, meaning that
18706 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
18707 essential freedoms}: to run the program, to study and change the program
18708 in source code form, to redistribute exact copies, and to distribute
18709 modified versions. Packages found in the GNU distribution provide only
18710 software that conveys these four freedoms.
18712 In addition, the GNU distribution follow the
18713 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
18714 software distribution guidelines}. Among other things, these guidelines
18715 reject non-free firmware, recommendations of non-free software, and
18716 discuss ways to deal with trademarks and patents.
18718 Some otherwise free upstream package sources contain a small and optional
18719 subset that violates the above guidelines, for instance because this subset
18720 is itself non-free code. When that happens, the offending items are removed
18721 with appropriate patches or code snippets in the @code{origin} form of the
18722 package (@pxref{Defining Packages}). This way, @code{guix
18723 build --source} returns the ``freed'' source rather than the unmodified
18727 @node Package Naming
18728 @subsection Package Naming
18730 @cindex package name
18731 A package has actually two names associated with it:
18732 First, there is the name of the @emph{Scheme variable}, the one following
18733 @code{define-public}. By this name, the package can be made known in the
18734 Scheme code, for instance as input to another package. Second, there is
18735 the string in the @code{name} field of a package definition. This name
18736 is used by package management commands such as
18737 @command{guix package} and @command{guix build}.
18739 Both are usually the same and correspond to the lowercase conversion of
18740 the project name chosen upstream, with underscores replaced with
18741 hyphens. For instance, GNUnet is available as @code{gnunet}, and
18742 SDL_net as @code{sdl-net}.
18744 We do not add @code{lib} prefixes for library packages, unless these are
18745 already part of the official project name. But @pxref{Python
18746 Modules} and @ref{Perl Modules} for special rules concerning modules for
18747 the Python and Perl languages.
18749 Font package names are handled differently, @pxref{Fonts}.
18752 @node Version Numbers
18753 @subsection Version Numbers
18755 @cindex package version
18756 We usually package only the latest version of a given free software
18757 project. But sometimes, for instance for incompatible library versions,
18758 two (or more) versions of the same package are needed. These require
18759 different Scheme variable names. We use the name as defined
18760 in @ref{Package Naming}
18761 for the most recent version; previous versions use the same name, suffixed
18762 by @code{-} and the smallest prefix of the version number that may
18763 distinguish the two versions.
18765 The name inside the package definition is the same for all versions of a
18766 package and does not contain any version number.
18768 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
18771 (define-public gtk+
18776 (define-public gtk+-2
18779 (version "2.24.20")
18782 If we also wanted GTK+ 3.8.2, this would be packaged as
18784 (define-public gtk+-3.8
18791 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
18792 @c for a discussion of what follows.
18793 @cindex version number, for VCS snapshots
18794 Occasionally, we package snapshots of upstream's version control system
18795 (VCS) instead of formal releases. This should remain exceptional,
18796 because it is up to upstream developers to clarify what the stable
18797 release is. Yet, it is sometimes necessary. So, what should we put in
18798 the @code{version} field?
18800 Clearly, we need to make the commit identifier of the VCS snapshot
18801 visible in the version string, but we also need to make sure that the
18802 version string is monotonically increasing so that @command{guix package
18803 --upgrade} can determine which version is newer. Since commit
18804 identifiers, notably with Git, are not monotonically increasing, we add
18805 a revision number that we increase each time we upgrade to a newer
18806 snapshot. The resulting version string looks like this:
18811 | | `-- upstream commit ID
18813 | `--- Guix package revision
18815 latest upstream version
18818 It is a good idea to strip commit identifiers in the @code{version}
18819 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
18820 aesthetics have a role to play here) as well as problems related to OS
18821 limits such as the maximum shebang length (127 bytes for the Linux
18822 kernel.) It is best to use the full commit identifiers in
18823 @code{origin}s, though, to avoid ambiguities. A typical package
18824 definition may look like this:
18828 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
18829 (revision "1")) ;Guix package revision
18831 (version (string-append "0.9-" revision "."
18832 (string-take commit 7)))
18835 (uri (git-reference
18836 (url "git://example.org/my-package.git")
18838 (sha256 (base32 "1mbikn@dots{}"))
18839 (file-name (string-append "my-package-" version
18845 @node Synopses and Descriptions
18846 @subsection Synopses and Descriptions
18848 @cindex package description
18849 @cindex package synopsis
18850 As we have seen before, each package in GNU@tie{}Guix includes a
18851 synopsis and a description (@pxref{Defining Packages}). Synopses and
18852 descriptions are important: They are what @command{guix package
18853 --search} searches, and a crucial piece of information to help users
18854 determine whether a given package suits their needs. Consequently,
18855 packagers should pay attention to what goes into them.
18857 Synopses must start with a capital letter and must not end with a
18858 period. They must not start with ``a'' or ``the'', which usually does
18859 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
18860 tool that frobs files''. The synopsis should say what the package
18861 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
18862 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
18863 matching a pattern''.
18865 Keep in mind that the synopsis must be meaningful for a very wide
18866 audience. For example, ``Manipulate alignments in the SAM format''
18867 might make sense for a seasoned bioinformatics researcher, but might be
18868 fairly unhelpful or even misleading to a non-specialized audience. It
18869 is a good idea to come up with a synopsis that gives an idea of the
18870 application domain of the package. In this example, this might give
18871 something like ``Manipulate nucleotide sequence alignments'', which
18872 hopefully gives the user a better idea of whether this is what they are
18875 Descriptions should take between five and ten lines. Use full
18876 sentences, and avoid using acronyms without first introducing them.
18877 Please avoid marketing phrases such as ``world-leading'',
18878 ``industrial-strength'', and ``next-generation'', and avoid superlatives
18879 like ``the most advanced''---they are not helpful to users looking for a
18880 package and may even sound suspicious. Instead, try to be factual,
18881 mentioning use cases and features.
18883 @cindex Texinfo markup, in package descriptions
18884 Descriptions can include Texinfo markup, which is useful to introduce
18885 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
18886 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
18887 should be careful when using some characters for example @samp{@@} and
18888 curly braces which are the basic special characters in Texinfo
18889 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
18890 such as @command{guix package --show} take care of rendering it
18893 Synopses and descriptions are translated by volunteers
18894 @uref{http://translationproject.org/domain/guix-packages.html, at the
18895 Translation Project} so that as many users as possible can read them in
18896 their native language. User interfaces search them and display them in
18897 the language specified by the current locale.
18899 Translation is a lot of work so, as a packager, please pay even more
18900 attention to your synopses and descriptions as every change may entail
18901 additional work for translators. In order to help them, it is possible
18902 to make recommendations or instructions visible to them by inserting
18903 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
18907 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
18908 (description "ARandR is designed to provide a simple visual front end
18909 for the X11 resize-and-rotate (RandR) extension. @dots{}")
18913 @node Python Modules
18914 @subsection Python Modules
18917 We currently package Python 2 and Python 3, under the Scheme variable names
18918 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
18919 To avoid confusion and naming clashes with other programming languages, it
18920 seems desirable that the name of a package for a Python module contains
18921 the word @code{python}.
18923 Some modules are compatible with only one version of Python, others with both.
18924 If the package Foo compiles only with Python 3, we name it
18925 @code{python-foo}; if it compiles only with Python 2, we name it
18926 @code{python2-foo}. If it is compatible with both versions, we create two
18927 packages with the corresponding names.
18929 If a project already contains the word @code{python}, we drop this;
18930 for instance, the module python-dateutil is packaged under the names
18931 @code{python-dateutil} and @code{python2-dateutil}. If the project name
18932 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
18935 @subsubsection Specifying Dependencies
18936 @cindex inputs, for Python packages
18938 Dependency information for Python packages is usually available in the
18939 package source tree, with varying degrees of accuracy: in the
18940 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
18942 Your mission, when writing a recipe for a Python package, is to map
18943 these dependencies to the appropriate type of ``input'' (@pxref{package
18944 Reference, inputs}). Although the @code{pypi} importer normally does a
18945 good job (@pxref{Invoking guix import}), you may want to check the
18946 following check list to determine which dependency goes where.
18951 We currently package Python 2 with @code{setuptools} and @code{pip}
18952 installed like Python 3.4 has per default. Thus you don't need to
18953 specify either of these as an input. @command{guix lint} will warn you
18957 Python dependencies required at run time go into
18958 @code{propagated-inputs}. They are typically defined with the
18959 @code{install_requires} keyword in @file{setup.py}, or in the
18960 @file{requirements.txt} file.
18963 Python packages required only at build time---e.g., those listed with
18964 the @code{setup_requires} keyword in @file{setup.py}---or only for
18965 testing---e.g., those in @code{tests_require}---go into
18966 @code{native-inputs}. The rationale is that (1) they do not need to be
18967 propagated because they are not needed at run time, and (2) in a
18968 cross-compilation context, it's the ``native'' input that we'd want.
18970 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
18971 frameworks. Of course if any of these packages is also required at
18972 run-time, it needs to go to @code{propagated-inputs}.
18975 Anything that does not fall in the previous categories goes to
18976 @code{inputs}, for example programs or C libraries required for building
18977 Python packages containing C extensions.
18980 If a Python package has optional dependencies (@code{extras_require}),
18981 it is up to you to decide whether to add them or not, based on their
18982 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
18989 @subsection Perl Modules
18992 Perl programs standing for themselves are named as any other package,
18993 using the lowercase upstream name.
18994 For Perl packages containing a single class, we use the lowercase class name,
18995 replace all occurrences of @code{::} by dashes and prepend the prefix
18997 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
18998 Modules containing several classes keep their lowercase upstream name and
18999 are also prepended by @code{perl-}. Such modules tend to have the word
19000 @code{perl} somewhere in their name, which gets dropped in favor of the
19001 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
19004 @node Java Packages
19005 @subsection Java Packages
19008 Java programs standing for themselves are named as any other package,
19009 using the lowercase upstream name.
19011 To avoid confusion and naming clashes with other programming languages,
19012 it is desirable that the name of a package for a Java package is
19013 prefixed with @code{java-}. If a project already contains the word
19014 @code{java}, we drop this; for instance, the package @code{ngsjava} is
19015 packaged under the name @code{java-ngs}.
19017 For Java packages containing a single class or a small class hierarchy,
19018 we use the lowercase class name, replace all occurrences of @code{.} by
19019 dashes and prepend the prefix @code{java-}. So the class
19020 @code{apache.commons.cli} becomes package
19021 @code{java-apache-commons-cli}.
19028 For fonts that are in general not installed by a user for typesetting
19029 purposes, or that are distributed as part of a larger software package,
19030 we rely on the general packaging rules for software; for instance, this
19031 applies to the fonts delivered as part of the X.Org system or fonts that
19032 are part of TeX Live.
19034 To make it easier for a user to search for fonts, names for other packages
19035 containing only fonts are constructed as follows, independently of the
19036 upstream package name.
19038 The name of a package containing only one font family starts with
19039 @code{font-}; it is followed by the foundry name and a dash @code{-}
19040 if the foundry is known, and the font family name, in which spaces are
19041 replaced by dashes (and as usual, all upper case letters are transformed
19043 For example, the Gentium font family by SIL is packaged under the name
19044 @code{font-sil-gentium}.
19046 For a package containing several font families, the name of the collection
19047 is used in the place of the font family name.
19048 For instance, the Liberation fonts consist of three families,
19049 Liberation Sans, Liberation Serif and Liberation Mono.
19050 These could be packaged separately under the names
19051 @code{font-liberation-sans} and so on; but as they are distributed together
19052 under a common name, we prefer to package them together as
19053 @code{font-liberation}.
19055 In the case where several formats of the same font family or font collection
19056 are packaged separately, a short form of the format, prepended by a dash,
19057 is added to the package name. We use @code{-ttf} for TrueType fonts,
19058 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
19063 @node Bootstrapping
19064 @section Bootstrapping
19066 @c Adapted from the ELS 2013 paper.
19068 @cindex bootstrapping
19070 Bootstrapping in our context refers to how the distribution gets built
19071 ``from nothing''. Remember that the build environment of a derivation
19072 contains nothing but its declared inputs (@pxref{Introduction}). So
19073 there's an obvious chicken-and-egg problem: how does the first package
19074 get built? How does the first compiler get compiled? Note that this is
19075 a question of interest only to the curious hacker, not to the regular
19076 user, so you can shamelessly skip this section if you consider yourself
19077 a ``regular user''.
19079 @cindex bootstrap binaries
19080 The GNU system is primarily made of C code, with libc at its core. The
19081 GNU build system itself assumes the availability of a Bourne shell and
19082 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
19083 `grep'. Furthermore, build programs---programs that run
19084 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
19085 (@pxref{Derivations}). Consequently, to be able to build anything at
19086 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
19087 Binutils, libc, and the other packages mentioned above---the
19088 @dfn{bootstrap binaries}.
19090 These bootstrap binaries are ``taken for granted'', though we can also
19091 re-create them if needed (more on that later).
19093 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
19095 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
19096 @c large image, it's hard to scroll. Oh well.
19097 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
19099 The figure above shows the very beginning of the dependency graph of the
19100 distribution, corresponding to the package definitions of the @code{(gnu
19101 packages bootstrap)} module. A similar figure can be generated with
19102 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
19105 guix graph -t derivation \
19106 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
19110 At this level of detail, things are
19111 slightly complex. First, Guile itself consists of an ELF executable,
19112 along with many source and compiled Scheme files that are dynamically
19113 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
19114 tarball shown in this graph. This tarball is part of Guix's ``source''
19115 distribution, and gets inserted into the store with @code{add-to-store}
19116 (@pxref{The Store}).
19118 But how do we write a derivation that unpacks this tarball and adds it
19119 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
19120 derivation---the first one that gets built---uses @code{bash} as its
19121 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
19122 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
19123 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
19124 the Guix source distribution, whose sole purpose is to allow the Guile
19125 tarball to be unpacked.
19127 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
19128 Guile that can be used to run subsequent build programs. Its first task
19129 is to download tarballs containing the other pre-built binaries---this
19130 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
19131 @code{ftp-client.scm} are used for this purpose. The
19132 @code{module-import.drv} derivations import those modules in a directory
19133 in the store, using the original layout. The
19134 @code{module-import-compiled.drv} derivations compile those modules, and
19135 write them in an output directory with the right layout. This
19136 corresponds to the @code{#:modules} argument of
19137 @code{build-expression->derivation} (@pxref{Derivations}).
19139 Finally, the various tarballs are unpacked by the
19140 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
19141 etc., at which point we have a working C tool chain.
19144 @unnumberedsubsec Building the Build Tools
19146 Bootstrapping is complete when we have a full tool chain that does not
19147 depend on the pre-built bootstrap tools discussed above. This
19148 no-dependency requirement is verified by checking whether the files of
19149 the final tool chain contain references to the @file{/gnu/store}
19150 directories of the bootstrap inputs. The process that leads to this
19151 ``final'' tool chain is described by the package definitions found in
19152 the @code{(gnu packages commencement)} module.
19154 The @command{guix graph} command allows us to ``zoom out'' compared to
19155 the graph above, by looking at the level of package objects instead of
19156 individual derivations---remember that a package may translate to
19157 several derivations, typically one derivation to download its source,
19158 one to build the Guile modules it needs, and one to actually build the
19159 package from source. The command:
19162 guix graph -t bag \
19163 -e '(@@@@ (gnu packages commencement)
19164 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
19168 produces the dependency graph leading to the ``final'' C
19169 library@footnote{You may notice the @code{glibc-intermediate} label,
19170 suggesting that it is not @emph{quite} final, but as a good
19171 approximation, we will consider it final.}, depicted below.
19173 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
19175 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
19176 The first tool that gets built with the bootstrap binaries is
19177 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
19178 for all the following packages. From there Findutils and Diffutils get
19181 Then come the first-stage Binutils and GCC, built as pseudo cross
19182 tools---i.e., with @code{--target} equal to @code{--host}. They are
19183 used to build libc. Thanks to this cross-build trick, this libc is
19184 guaranteed not to hold any reference to the initial tool chain.
19186 From there the final Binutils and GCC (not shown above) are built.
19188 from the final Binutils, and links programs against the just-built libc.
19189 This tool chain is used to build the other packages used by Guix and by
19190 the GNU Build System: Guile, Bash, Coreutils, etc.
19192 And voilà! At this point we have the complete set of build tools that
19193 the GNU Build System expects. These are in the @code{%final-inputs}
19194 variable of the @code{(gnu packages commencement)} module, and are
19195 implicitly used by any package that uses @code{gnu-build-system}
19196 (@pxref{Build Systems, @code{gnu-build-system}}).
19199 @unnumberedsubsec Building the Bootstrap Binaries
19201 @cindex bootstrap binaries
19202 Because the final tool chain does not depend on the bootstrap binaries,
19203 those rarely need to be updated. Nevertheless, it is useful to have an
19204 automated way to produce them, should an update occur, and this is what
19205 the @code{(gnu packages make-bootstrap)} module provides.
19207 The following command builds the tarballs containing the bootstrap
19208 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
19209 of Coreutils and other basic command-line tools):
19212 guix build bootstrap-tarballs
19215 The generated tarballs are those that should be referred to in the
19216 @code{(gnu packages bootstrap)} module mentioned at the beginning of
19219 Still here? Then perhaps by now you've started to wonder: when do we
19220 reach a fixed point? That is an interesting question! The answer is
19221 unknown, but if you would like to investigate further (and have
19222 significant computational and storage resources to do so), then let us
19226 @section Porting to a New Platform
19228 As discussed above, the GNU distribution is self-contained, and
19229 self-containment is achieved by relying on pre-built ``bootstrap
19230 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
19231 operating system kernel, CPU architecture, and application binary
19232 interface (ABI). Thus, to port the distribution to a platform that is
19233 not yet supported, one must build those bootstrap binaries, and update
19234 the @code{(gnu packages bootstrap)} module to use them on that platform.
19236 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
19237 When everything goes well, and assuming the GNU tool chain supports the
19238 target platform, this can be as simple as running a command like this
19242 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
19245 For this to work, the @code{glibc-dynamic-linker} procedure in
19246 @code{(gnu packages bootstrap)} must be augmented to return the right
19247 file name for libc's dynamic linker on that platform; likewise,
19248 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
19249 taught about the new platform.
19251 Once these are built, the @code{(gnu packages bootstrap)} module needs
19252 to be updated to refer to these binaries on the target platform. That
19253 is, the hashes and URLs of the bootstrap tarballs for the new platform
19254 must be added alongside those of the currently supported platforms. The
19255 bootstrap Guile tarball is treated specially: it is expected to be
19256 available locally, and @file{gnu/local.mk} has rules do download it for
19257 the supported architectures; a rule for the new platform must be added
19260 In practice, there may be some complications. First, it may be that the
19261 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
19262 above) is not recognized by all the GNU tools. Typically, glibc
19263 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
19264 configure flag (see @code{gcc.scm} for examples of how to handle this).
19265 Second, some of the required packages could fail to build for that
19266 platform. Lastly, the generated binaries could be broken for some
19269 @c *********************************************************************
19270 @include contributing.texi
19272 @c *********************************************************************
19273 @node Acknowledgments
19274 @chapter Acknowledgments
19276 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
19277 which was designed and
19278 implemented by Eelco Dolstra, with contributions from other people (see
19279 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
19280 management, and promoted unprecedented features, such as transactional
19281 package upgrades and rollbacks, per-user profiles, and referentially
19282 transparent build processes. Without this work, Guix would not exist.
19284 The Nix-based software distributions, Nixpkgs and NixOS, have also been
19285 an inspiration for Guix.
19287 GNU@tie{}Guix itself is a collective work with contributions from a
19288 number of people. See the @file{AUTHORS} file in Guix for more
19289 information on these fine people. The @file{THANKS} file lists people
19290 who have helped by reporting bugs, taking care of the infrastructure,
19291 providing artwork and themes, making suggestions, and more---thank you!
19294 @c *********************************************************************
19295 @node GNU Free Documentation License
19296 @appendix GNU Free Documentation License
19297 @cindex license, GNU Free Documentation License
19298 @include fdl-1.3.texi
19300 @c *********************************************************************
19301 @node Concept Index
19302 @unnumbered Concept Index
19305 @node Programming Index
19306 @unnumbered Programming Index
19307 @syncodeindex tp fn
19308 @syncodeindex vr fn
19313 @c Local Variables:
19314 @c ispell-local-dictionary: "american";