[ClusterLabs] Informing RAs about recovery: failed resource recovery, or any start-stop cycle?
aspiers at suse.com
Fri May 20 11:50:21 EDT 2016
Ken Gaillot <kgaillot at redhat.com> wrote:
> A recent thread discussed a proposed new feature, a new environment
> variable that would be passed to resource agents, indicating whether a
> stop action was part of a recovery.
> Since that thread was long and covered a lot of topics, I'm starting a
> new one to focus on the core issue remaining:
> The original idea was to pass the number of restarts remaining before
> the resource will no longer tried to be started on the same node. This
> involves calculating (fail-count - migration-threshold), and that
> implies certain limitations: (1) it will only be set when the cluster
> checks migration-threshold; (2) it will only be set for the failed
> resource itself, not for other resources that may be recovered due to
> dependencies on it.
> Ulrich Windl proposed an alternative: setting a boolean value instead. I
> forgot to cc the list on my reply, so I'll summarize now: We would set a
> new variable like OCF_RESKEY_CRM_recovery=true whenever a start is
> scheduled after a stop on the same node in the same transition. This
> would avoid the corner cases of the previous approach; instead of being
> tied to migration-threshold, it would be set whenever a recovery was
> being attempted, for any reason. And with this approach, it should be
> easier to set the variable for all actions on the resource
> (demote/stop/start/promote), rather than just the stop.
> I think the boolean approach fits all the envisioned use cases that have
> been discussed. Any objections to going that route instead of the count?
I think that sounds fine to me. Thanks!
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