Stop application under cluster for maintenance

Question

Hi
I  have a application which is under control of  the  cluster  and needs to be shutdown and startup manually for  maintenance like patching , how can I shutdown the application without it  causing the  resource group to switch over and start the application on another node and after  the  maintenance is   successful pass the control  back to the cluster
TIA

Answer 1

Hi,
when doing planned maintenance (like applying a patch or upgrading the application software) for an application under cluster control, the safest way is to:
disable the cluster resource (clrs disable <resourcename>)
perform the maintenance
verify everything is working as expected
enable the cluster resource again (clrs enable <resourcename>)
There is also the possibility to suspend the whole resource group, where the application resource is configured in, by doing a "clrg suspend <resourcegroupname".
Then the cluster framework will not try to restart this resource group or trigger failover for it.
The resource group can be resumed by "clrg resume <resourcegroupname>".
But here it really depends on the scope of change you apply to an application, if the data service monitor for the application resource can really continue to perform monitoring as before.
In some cases the data service monitor is not only probe based, but does also perform PMF based monitoring, ie. it monitors the specific process ids (pids) that got started by its start method.
If you then manually stop the application, PMF might no longer see any of those pids, and thus determine a failed resource.
That is why in general for performing maintenance on an application, you should start with disabling the resource. And enable it back once the maintenance is finished.
Regards
             Thorsten