Provided by: ganeti-3.1_3.1.0~rc2-3_all 
Name
ganeti-watcher - Ganeti cluster watcher
Synopsis
ganeti-watcher [--debug] [--job-age=*age* ] [--ignore-pause] [--rapi-ip=*IP*] [--no-verify-disks]
[--no-strict]
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 --no-strict option runs the group verify disks job in a non-strict mode. This only verifies those
disks whose node locks could be acquired in a best-effort attempt and will skip nodes that are recognized
as busy with other jobs.
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 (/etc/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 /var/lib/ganeti/watcher.GROUP-UUID.data
(only used on the master) and a log file at /var/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 /var/lib/ganeti/watcher.*.data
rm -f /var/lib/ganeti/watcher.*.instance-status
rm -f /var/lib/ganeti/instance-status
And then re-run the watcher.
REPORTING BUGS
Report bugs to the project's issue tracker or contact the developers using the Ganeti mailing list.
SEE ALSO
Ganeti overview and specifications: ganeti(7) (general overview), ganeti-os-interface(7) (guest OS
definitions), ganeti-extstorage-interface(7) (external storage providers).
Ganeti commands: gnt-cluster(8) (cluster-wide commands), gnt-job(8) (job-related commands), gnt-node(8)
(node-related commands), gnt-instance(8) (instance commands), gnt-os(8) (guest OS commands),
gnt-storage(8) (storage commands), gnt-group(8) (node group commands), gnt-backup(8) (instance
import/export commands), gnt-debug(8) (debug commands).
Ganeti daemons: ganeti-watcher(8) (automatic instance restarter), ganeti-cleaner(8) (job queue cleaner),
ganeti-noded(8) (node daemon), ganeti-rapi(8) (remote API daemon).
Ganeti htools: htools(1) (generic binary), hbal(1) (cluster balancer), hspace(1) (capacity calculation),
hail(1) (IAllocator plugin), hscan(1) (data gatherer from remote clusters), hinfo(1) (cluster information
printer), mon-collector(7) (data collectors interface).
COPYRIGHT
Copyright (C) 2006-2015 Google Inc. All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided
that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and
the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Ganeti ganeti-watcher(8)