Ubuntu Manpage: ganeti-watcher - Ganeti cluster watcher

Provided by: ganeti-3.0_3.0.2-1ubuntu1_all

Name

       ganeti-watcher - Ganeti cluster watcher

Synopsis

       ganeti-watcher [--debug] [--job-age=*age* ] [--ignore-pause] [--rapi-ip=*IP*] [--no-verify-disks]

DESCRIPTION

The ganeti-watcher is a periodically run script which is responsible for keeping the instances in the
correct status. It has two separate functions, one for the master node and another one that runs on
every node.

If the watcher is disabled at cluster level (via the gnt-cluster watcher pause command), it will exit
without doing anything. The cluster-level pause can be overridden via the --ignore-pause option, for
example if during a maintenance the watcher needs to be disabled in general, but the administrator wants
to run it just once.

The --debug option will increase the verbosity of the watcher and also activate logging to the standard
error.

The --rapi-ip option needs to be set if the RAPI daemon was started with a particular IP (using the -b
option). The two options need to be exactly the same to ensure that the watcher can reach the RAPI
interface.

Master operations
Its primary function is to try to keep running all instances which are marked as up in the configuration
file, by trying to start them a limited number of times.

Another function is to "repair" DRBD links by reactivating the block devices of instances which have
secondaries on nodes that have been rebooted.

Additionally, it will verify and repair degraded DRBD disks; this will not happen, if the --no-verify-
disks option is given.

The watcher will also archive old jobs (older than the age given via the --job-age option, which defaults
to 6 hours), in order to keep the job queue manageable.

Node operations
The watcher will restart any down daemons that are appropriate for the current node.

In addition, it will execute any scripts which exist under the "watcher" directory in the Ganeti hooks
directory (@SYSCONFDIR@/ganeti/hooks). This should be used for lightweight actions, like starting any
extra daemons.

If the cluster parameter maintain_node_health is enabled, then the watcher will also shutdown instances
and DRBD devices if the node is declared as offline by known master candidates.

The watcher does synchronous queries but will submit jobs for executing the changes. Due to locking, it
could be that the jobs execute much later than the watcher submits them.

FILES

       The command has a set of state files (one per group) located at @LOCALSTATEDIR@/lib/ganeti/watcher.GROUP-
       UUID.data (only used on the master) and a log file at @LOCALSTATEDIR@/log/ganeti/watcher.log.  Removal of
       either  file(s)  will  not  affect  correct  operation; the removal of the state file will just cause the
       restart counters for the instances to reset to zero, and mark nodes as freshly rebooted (so  for  example
       DRBD minors will be re-activated).

       In  some cases, it's even desirable to reset the watcher state, for example after maintenance actions, or
       when you want to simulate the reboot of all nodes, so in this case, you can remove all state files:

              rm -f @LOCALSTATEDIR@/lib/ganeti/watcher.*.data
              rm -f @LOCALSTATEDIR@/lib/ganeti/watcher.*.instance-status
              rm -f @LOCALSTATEDIR@/lib/ganeti/instance-status

       And then re-run the watcher.

REPORTING BUGS

       Report bugs to the project's  issue  tracker  (https://github.com/ganeti/ganeti/issues)  or  contact  the
       developers using the Ganeti mailing list.

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