Resurrecting an old thread, because I stumbled on something relevant ... There had been some discussion about having the ability to run a more useful monitor operation on an otherwise systemd-based resource. We had talked about a couple approaches with advantages and disadvantages.
I had completely forgotten about an older capability of pacemaker that could be repurposed here: the (undocumented) "container" meta-attribute. It was originally designed for running nagios checks on services inside a virtual domain. The idea is that you can create an OCF VirtualDomain resource, then create a nagios resource with its container set to the VirtualDomain. The effect is this: a resource with the container meta-attribute will be started, stopped, and monitored normally, but if its monitor fails, it will be recovered by recovering its container instead. Also, the resource will be colocated with its container resource, and ordered relative to it. This works with the nagios use case because start and stop are essentially no-ops for nagios resources. The nagios resource can "start" on the same host that the VirtualDomain starts on, and the host will run the nagios check at each monitor interval. If the monitor fails, pacemaker will recover the VirtualDomain. I haven't tested it, but this approach should work identically with a systemd resource and a custom OCF resource with the extended monitor. The OCF resource would function as a dummy resource (to know when it's "running" or not), so start/stop would only set up the dummy state. If the monitor fails, the systemd resource should be recovered. If someone wants to verify that works, I'll make sure that the documentation gets updated. -- Ken Gaillot <[email protected]> _______________________________________________ Developers mailing list [email protected] http://lists.clusterlabs.org/mailman/listinfo/developers
