[Pacemaker] Primitives running on multiple hosts

[Lars Marowsky-Bree]

On 2012-03-27T09:17:15, Dominik Epple <Dominik.Epple at EMEA.NEC.COM> wrote:

> Since I don't know what strange events may have lead to this situation (perhaps it was a manual manipulation), I created the following testcase to investigate this: configure a cluster, add some failover IP address primitive resource, let pacemaker start in on one host. Configure this IP address manually on the other host. Hope that pacemaker will detect it and react somehow (stop the resource, or do some stonith, or whatever).
> 
> But even with some monitoring op defined, pacemaker seems only to check that the resource is running on the host it is scheduled for, and it does not check that the resource is not running on the host where it should not run. (I verified that the resource agent itself determines the status correctly, i.e. on the started resource, the monitoring action returns 0, on the stopped resource, it returns 7.)
> 
> Is this observation correct? Is this the expected behavior? Is it possible to configure the resource such that it is checked that the resource is stopped where it is expected to be stopped?

Pacemaker will explicitly check for resources being active on start-up
on a node (we call that particular call to monitor "probe").

After that, we don't expect admins to manually mess things up. ;-)

You can, however, configure an explicit monitor for role="Stopped",
which will be able to detect primitives that are active where they
shouldn't be (within the configured interval). Yan added that on my
request for feature parity with another well-known cluster solution.

That will eventually catch them, but of course, if it really matters,
you'll already be looking at data/service corruption in the meantime.



Regards,
    Lars

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