On Fri, Mar 5, 2021 at 10:13 AM Ken Gaillot <[email protected]> wrote:
> On Fri, 2021-03-05 at 11:39 +0100, Ulrich Windl wrote: > > Hi! > > > > I'm unsure what actually causes a problem I see (a resource was > > "detected running" when it actually was not), but I'm sure some probe > > started on cluster node start cannot provide a useful result until > > some other resource has been started. AFAIK there is no way to make a > > probe obey odering or colocation constraints, so the only work-around > > seems to be a delay. However I'm unsure whether probes can actually > > be delayed. > > > > Ideas? > > Ordered probes are a thorny problem that we've never been able to come > up with a general solution for. We do order certain probes where we > have enough information to know it's safe. The problem is that it is > very easy to introduce ordering loops. > > I don't remember if there any workarounds. > Maybe as a workaround: - Add an ocf:pacemaker:attribute resource after-and-with rsc1 - Then configure a location rule for rsc2 with resource-discovery=never and score=-INFINITY with expression (in pseudocode) "attribute is not set to active value" I haven't tested but that might cause rsc2's probe to wait until rsc1 is active. And of course, use the usual constraints/rules to ensure rsc2's probe only runs on rsc1's node. > > Despite of that I wonder whether some probe/monitor returncode like > > OCF_NOT_READY would make sense if the operation detects that it > > cannot return a current status (so both "running" and "stopped" would > > be as inadequate as "starting" and "stopping" would be (despite of > > the fact that the latter two do not exist)). > This seems logically reasonable, independent of any implementation complexity and considerations of what we would do with that return code. > > Regards, > > Ulrich > -- > Ken Gaillot <[email protected]> > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ > > -- Regards, Reid Wahl, RHCA Senior Software Maintenance Engineer, Red Hat CEE - Platform Support Delivery - ClusterHA
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