doc/man-pages/pod5/BosConfig.pod

   1 =head1 NAME
   2
   3 BosConfig - Defines server processes for the BOS Server to monitor
   4
   5 =head1 DESCRIPTION
   6
   7 The F<BosConfig> file lists the processes that the Basic OverSeer (BOS)
   8 Server monitors on its server machine, and thus defines which AFS server
   9 processes run on the machine. It specifies how the BOS Server reacts when
  10 a process fails, and also defines the times at which the BOS Server
  11 automatically restarts processes as part of performance maintenance.  The
  12 file must reside in the F</usr/afs/local> directory on each AFS server
  13 machine.
  14
  15 A server process entry in the F<BosConfig> file records the following
  16 information:
  17
  18 =over 4
  19
  20 =item *
  21
  22 The I<entry type>, which is one of the following:
  23
  24 =over 4
  25
  26 =item cron
  27
  28 Designates a server process that runs periodically instead of
  29 continuously. The BOS Server starts a cron process only at specified
  30 times, not whenever it fails. All standard AFS process entries except
  31 C<fs> are simple (there are no standard cron processes).
  32
  33 =item fs
  34
  35 Designates a group of interdependent server processes. If one of the
  36 processes fails, the BOS Server must coordinate its restart with the
  37 restart of the other processes in the group, possibly by stopping them
  38 first.
  39
  40 There is only one standard entry of this type, for which the conventional
  41 name is C<fs>. It combines three server processes: the File Server
  42 (B<fileserver> process), the Volume Server (B<volserver> process), and the
  43 Salvager (B<salvager> process). These processes all operate on the same
  44 data--the AFS data stored on an AFS server machine's F</vicep> partitions
  45 and mounted in the AFS filespace--but in different ways. Grouping the
  46 processes prevents them from attempting to access the same data
  47 simultaneously, which can cause corruption.
  48
  49 During normal operation, the Salvager process is not active. If the File
  50 Server process fails, however, the BOS Server stops the Volume Server
  51 process and runs the Salvager process to correct any corruption that
  52 resulted from the failure. (The administrator can also issue the B<bos
  53 salvage> command to invoke the Salvager process.) If the Volume Server
  54 fails, the BOS Server can restart it without stopping the File Server or
  55 running the Salvager.
  56
  57 =item simple
  58
  59 Designates a server process that runs independently of any other on the
  60 server machine. If a simple process fails, the BOS Server does not have to
  61 coordinate its restart with any other process.
  62
  63 =back
  64
  65 =item *
  66
  67 The I<entry name>. The conventional name for an entry in the F<BosConfig>
  68 file and the associated process matches the binary filename. When issuing
  69 any B<bos> command that takes the B<-instance> argument, identify each
  70 process by the name used in the F<BosConfig> file. For a list of the
  71 names, see the B<bos create> reference page.
  72
  73 =item *
  74
  75 The process's I<status flag>, which determines whether the BOS Server
  76 attempts to start the process in two cases: each time the BOS Server
  77 itself restarts, and when the process fails. The F<BosConfig> file
  78 currently uses a binary notation to indicate whether the BOS Server
  79 attempts to restart the process as necessary or does not monitor it at
  80 all. For the sake of clarity, the AFS documentation refers to the flags as
  81 C<Run> and C<NotRun> instead.  Only a system administrator, not the BOS
  82 Server, can change the flag.
  83
  84 =item *
  85
  86 One or more I<command parameters> which the BOS Server invokes to start
  87 the process or processes associated with the entry:
  88
  89 =over 4
  90
  91 =item *
  92
  93 A C<cron> entry has two command parameters, the first the complete
  94 pathname to the program, and the second the time at which the BOS Server
  95 invokes the program.
  96
  97 =item *
  98
  99 The C<fs> entry has three command parameters, each the complete pathname
 100 to the B<fileserver>, B<volserver>, and B<salvager> programs, in that
 101 order.
 102
 103 =item *
 104
 105 A C<simple> entry has only one command parameter, the complete pathname to
 106 the program.
 107
 108 =back
 109
 110 =back
 111
 112 In addition to server process entries, the F<BosConfig> file specifies the
 113 times at which the BOS Server performs two types of automatic process
 114 restarts:
 115
 116 =over 4
 117
 118 =item *
 119
 120 The I<general restart> time at which the BOS Server restarts itself and
 121 then each process for which the entry in the F<BosConfig> file has status
 122 flag C<Run>. The default setting is Sunday at 4:00 a.m.
 123
 124 =item *
 125
 126 The I<binary restart> time at which the BOS Server restarts any server
 127 process for which the time stamp on the binary file in the F</usr/afs/bin>
 128 directory is later than the last restart time for the process. The default
 129 is 5:00 a.m.
 130
 131 =back
 132
 133 Finally, there is an entry specifying whether the BOS Server will start in
 134 restricted mode.
 135
 136 Although the F<BosConfig> file is in ASCII format, it is normally best not
 137 to use a text editor to alter it.  The parser is very picky, and
 138 incorrectly formatted entries can prevent server startup in ways that are
 139 difficult to diagnose. Instead, use the appropriate commands from the
 140 B<bos> command suite:
 141
 142 =over 4
 143
 144 =item *
 145
 146 The B<bos create> command to create an entry in the file and start the
 147 associated process.
 148
 149 =item *
 150
 151 The B<bos delete> command to remove an entry from the file after the B<bos
 152 stop> command is used to stop the associated process.
 153
 154 =item *
 155
 156 The B<bos getrestart> command to display the times at which the BOS Server
 157 performs automatic restarts.
 158
 159 =item *
 160
 161 The B<bos getrestricted> command to display whether the BOS Server is running
 162 in restricted mode.
 163
 164 =item *
 165
 166 The B<bos setrestart> command to set the times at which the BOS Server
 167 performs automatic process restarts.
 168
 169 =item *
 170
 171 The B<bos setrestricted> command to place the BOS Server in restricted mode.
 172
 173 =item *
 174
 175 The B<bos start> command to change an entry's status flag to C<Run> and
 176 start the associated process.
 177
 178 =item *
 179
 180 The B<bos status> command to display all processes listed in the file.
 181
 182 =item *
 183
 184 The B<bos stop> command to change an entry's status flag to C<NotRun> and
 185 stop the associated process.
 186
 187 =back
 188
 189 There are also bos commands that start and stop processes without changing
 190 entries in the F<BosConfig> file. The BOS Server reads the F<BosConfig>
 191 file only when it starts, transferring the information into its
 192 memory. Thus a process's status as represented in the BOS Server's memory
 193 can diverge from its status in the F<BosConfig> file. The following
 194 commands change a process's status in the BOS Server's memory only:
 195
 196 =over 4
 197
 198 =item *
 199
 200 The B<bos restart> command restarts a specified set of processes, all
 201 processes, or all processes other than the BOS Server.
 202
 203 =item *
 204
 205 The B<bos shutdown> command stops a process.
 206
 207 =item *
 208
 209 The B<bos startup> command starts a process.
 210
 211 =back
 212
 213 When the BOS Server shuts down, it rewrites F<BosConfig>, discarding any
 214 changes made manually to that file.  To change the configuration for the
 215 next BOS Server restart, instead write a new file to F<BosConfig.new>.  If
 216 F<BosConfig.new> exists when the BOS Server starts, F<BosConfig> will be
 217 replaced by F<BosConfig.new> before the BOS Server reads its configuration.
 218 Note that the BOS Server will notice a new F<BosConfig.new> file whenever the
 219 I<general restart> time is reached, if one is configured, since the BOS Server
 220 restarts itself at that time.
 221
 222 =head1 SEE ALSO
 223
 224 L<bos_create(8)>,
 225 L<bos_delete(8)>,
 226 L<bos_getrestart(8)>,
 227 L<bos_getrestricted(8)>,
 228 L<bos_restart(8)>,
 229 L<bos_setrestart(8)>,
 230 L<bos_setrestricted(8)>,
 231 L<bos_shutdown(8)>,
 232 L<bos_start(8)>,
 233 L<bos_startup(8)>,
 234 L<bos_status(8)>,
 235 L<bos_stop(8)>,
 236 L<bos_salvage(8)>,
 237 L<fileserver(8)>,
 238 L<salvager(8)>,
 239 L<volserver(8)>
 240
 241 =head1 COPYRIGHT
 242
 243 IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
 244
 245 This documentation is covered by the IBM Public License Version 1.0.  It was
 246 converted from HTML to POD by software written by Chas Williams and Russ
 247 Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.