NAME¶
BosConfig - Defines server processes for the BOS Server to monitor
DESCRIPTION¶
The
BosConfig file lists the processes that the Basic OverSeer (BOS)
Server monitors on its server machine, and thus defines which AFS server
processes run on the machine. It specifies how the BOS Server reacts when a
process fails, and also defines the times at which the BOS Server
automatically restarts processes as part of performance maintenance. The file
must reside in the
/var/lib/openafs/local directory on each AFS server
machine.
A server process entry in the
BosConfig file records the following
information:
- •
- The entry type, which is one of the following:
- cron
- Designates a server process that runs periodically instead of
continuously. The BOS Server starts a cron process only at specified
times, not whenever it fails. All standard AFS process entries except
"fs" are simple (there are no standard cron processes).
- fs
- Designates a group of interdependent server processes. If one of the
processes fails, the BOS Server must coordinate its restart with the
restart of the other processes in the group, possibly by stopping them
first.
There is only one standard entry of this type, for which the conventional
name is "fs". It combines three server processes: the File
Server ( fileserver process), the Volume Server (volserver
process), and the Salvager ( salvager process). These processes all
operate on the same data--the AFS data stored on an AFS server machine's
/vicep partitions and mounted in the AFS filespace--but in
different ways. Grouping the processes prevents them from attempting to
access the same data simultaneously, which can cause corruption.
During normal operation, the Salvager process is not active. If the File
Server process fails, however, the BOS Server stops the Volume Server
process and runs the Salvager process to correct any corruption that
resulted from the failure. (The administrator can also issue the
bos salvage command to invoke the Salvager process.) If the
Volume Server fails, the BOS Server can restart it without stopping the
File Server or running the Salvager.
- simple
- Designates a server process that runs independently of any other on the
server machine. If a simple process fails, the BOS Server does not have to
coordinate its restart with any other process.
- •
- The entry name. The conventional name for an entry in the
BosConfig file and the associated process matches the binary
filename. When issuing any bos command that takes the
-instance argument, identify each process by the name used in the
BosConfig file. For a list of the names, see the bos create
reference page.
- •
- The process's status flag, which determines whether the BOS Server
attempts to start the process in two cases: each time the BOS Server
itself restarts, and when the process fails. The BosConfig file
currently uses a binary notation to indicate whether the BOS Server
attempts to restart the process as necessary or does not monitor it at
all. For the sake of clarity, the AFS documentation refers to the flags as
"Run" and "NotRun" instead. Only a system
administrator, not the BOS Server, can change the flag.
- •
- One or more command parameters which the BOS Server invokes to
start the process or processes associated with the entry:
- •
- A "cron" entry has two command parameters, the first the
complete pathname to the program, and the second the time at which the BOS
Server invokes the program.
- •
- The "fs" entry has three command parameters, each the complete
pathname to the fileserver, volserver, and salvager
programs, in that order.
- •
- A "simple" entry has only one command parameter, the complete
pathname to the program.
In addition to server process entries, the
BosConfig file specifies the
times at which the BOS Server performs two types of automatic process
restarts:
- •
- The general restart time at which the BOS Server restarts itself
and then each process for which the entry in the BosConfig file has
status flag "Run". The default setting is Sunday at 4:00
a.m.
- •
- The binary restart time at which the BOS Server restarts any server
process for which the time stamp on the binary file in the
/usr/lib/openafs directory is later than the last restart time for
the process. The default is 5:00 a.m.
Finally, there is an entry specifying whether the BOS Server will start in
restricted mode.
Although the
BosConfig file is in ASCII format, it is normally best not
to use a text editor to alter it. The parser is very picky, and incorrectly
formatted entries can prevent server startup in ways that are difficult to
diagnose. Instead, use the appropriate commands from the
bos command
suite:
- •
- The bos create command to create an entry in the file and start the
associated process.
- •
- The bos delete command to remove an entry from the file after the
bos stop command is used to stop the associated
process.
- •
- The bos getrestart command to display the times at which the BOS
Server performs automatic restarts.
- •
- The bos getrestricted command to display whether the BOS Server is
running in restricted mode.
- •
- The bos setrestart command to set the times at which the BOS Server
performs automatic process restarts.
- •
- The bos setrestricted command to place the BOS Server in restricted
mode.
- •
- The bos start command to change an entry's status flag to
"Run" and start the associated process.
- •
- The bos status command to display all processes listed in the
file.
- •
- The bos stop command to change an entry's status flag to
"NotRun" and stop the associated process.
There are also bos commands that start and stop processes without changing
entries in the
BosConfig file. The BOS Server reads the
BosConfig file only when it starts, transferring the information into
its memory. Thus a process's status as represented in the BOS Server's memory
can diverge from its status in the
BosConfig file. The following
commands change a process's status in the BOS Server's memory only:
- •
- The bos restart command restarts a specified set of processes, all
processes, or all processes other than the BOS Server.
- •
- The bos shutdown command stops a process.
- •
- The bos startup command starts a process.
When the BOS Server shuts down, it rewrites
BosConfig, discarding any
changes made manually to that file. To change the configuration for the next
BOS Server restart, instead write a new file to
BosConfig.new. If
BosConfig.new exists when the BOS Server starts, it will rename that
file to
BosConfig before reading its configuration.
SEE ALSO¶
bos_create(8),
bos_delete(8),
bos_getrestart(8),
bos_getrestricted(8),
bos_restart(8),
bos_setrestart(8),
bos_setrestricted(8),
bos_shutdown(8),
bos_start(8),
bos_startup(8),
bos_status(8),
bos_stop(8),
bos_salvage(8),
fileserver(8),
salvager(8),
volserver(8)
COPYRIGHT¶
IBM Corporation 2000. <
http://www.ibm.com/> All Rights Reserved.
This documentation is covered by the IBM Public License Version 1.0. It was
converted from HTML to POD by software written by Chas Williams and Russ
Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.