[Pacemaker] Should monitor operations be stopped after a resource is unmanaged?

[Tim Serong]

On 4/2/2011 at 09:42 PM, Ron Kerry <rkerry at sgi.com> wrote: 
> On 7/22/64 2:59 PM, Serge Dubrouski wrote: 
> > On Fri, Apr 1, 2011 at 2:09 PM, Ron Kerry <rkerry at sgi.com> wrote: 
> >  > On 7/22/64 2:59 PM, Pavel Levshin wrote: 
> >  >> 
> >  >> 01.04.2011 18:36, Ron Kerry: 
> >  >> > Folks - 
> >  >> > 
> >  >> > Consider a running cluster with all resources managed. We want to stop 
> >  >> > and quickly restart a particular resource without impacting other 
> >  >> > resources. The software stack running on the system can deal with this 
> >  >> > sort of temporary outage. We perform the following actions: 
> >  >> > * unmanage the resource 
> >  >> > * stop the resource 
> >  >> > * start the resource 
> >  >> > * manage the resource 
> >  >> > 
> >  >> > The above procedure is sometimes successful. However, we will also 
> >  >> > sometimes get a resource monitor failure after stopping the resource. 
> >  >> > It is clear that the monitor operation was not stopped (at least not 
> >  >> > immediately) by unmanaging the resource. 
> >  >> 
> >  >> Unmanaged resource cannot be started and stopped, but can still be 
> >  >> monitored. 
> >  > 
> >  > So unmanaged really means the resource is still being managed to some 
> >  > degree? 
> > 
> > It means that Pacemaker still wants to know its state. What kind of 
> > problem does it create? 
> > 
>  
> An unmanaged resource whoose monitor is still running will cause a monitor  
> failure when the resource  
> is stopped. Pacemaker then takes the 'onfail' action defined for the monitor  
> operation. In other  
> words, the resource is still being managed to some degree. If the monitor  
> operation was still  
> running but no action was taken as a result of the monitor operation  
> outcome, there would be no issue. 

Try "crm configure property maintenance-mode=true".  Admittedly this
affects the entire cluster, but it will ensure no starts, stops or
monitors...

Regards,

Tim


-- 
Tim Serong <tserong at novell.com>
Senior Clustering Engineer, OPS Engineering, Novell Inc.