[ClusterLabs] Pacemaker ordering constraints and resource failures
Devin A. Bougie
devin.bougie at cornell.edu
Wed Aug 8 20:47:47 UTC 2018
Many thanks for all of the replies. Perhaps my choice of dummy resource names was misleading, as our production resources aren’t really in a master / slave relationship. Just incase it helps, here is what we want to achieve.
- only start resource B if resource A is already running.
- if both resources are running and resource A stops, continue running resource B (hence the non-symmetrical ordering constraint)
- if resource B fails and resource A is disabled, resource B should not restart until resource A is started
It sounds like that should be doable with our existing constraints, so I’ll go ahead and open a bug at bugs.clusterlabs.org.
> On Aug 6, 2018, at 1:07 PM, Devin A. Bougie <devin.bougie at cornell.edu> wrote:
> What is the best way to make sure pacemaker doesn’t attempt to recover or restart a resource if a resource it depends on is not started?
> For example, we have two dummy resources that simply sleep - master_sleep and slave_sleep. We then have a non-symmetrical ordering constraint that ensures master_sleep is started before slave_sleep:
> start master_sleep then start slave_sleep (kind:Mandatory) (non-symmetrical)
> This works as expected when both resources are disabled. If we enable slave_sleep first, it won’t actually start until after master_sleep if enabled and started.
> However, if slave_sleep dies when master_sleep is disabled and stopped, pacemaker recovers and restarts slave_sleep. For example:
> - enable master_sleep, and wait for it to start
> - enable slave_sleep, and wait for it to start
> - disable master_sleep, and wait for it to stop
> - kill the slave_sleep process (or, “pcs resource debug-stop slave_sleep”)
> - pacemaker recovers and restarts slave_sleep, even though master_sleep is disabled and stopped.
> Is this the expected behavior, and is there any way to change it? I’m happy to provide logs if that would help.
> Many thanks,
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