[Pacemaker] Can Master/Slave resource transit from Master to Stopped directly ?

[Lars Ellenberg]

On Tue, Mar 06, 2012 at 08:18:28PM +0900, Takatoshi MATSUO wrote:
> Hi Dejan
> 
> 2012/3/6 Dejan Muhamedagic <dejanmm at fastmail.fm>:
> > Hi,
> >
> > On Tue, Mar 06, 2012 at 01:15:45PM +0900, Takatoshi MATSUO wrote:
> >> Hi
> >>
> >> I want Pacemaker to transit from Master to Stopped directly on demote
> >> without failcount
> >> for managing PostgreSQL streaming replication.
> >> Can Pacemaker do this ?
> >
> > What the RA should do on demote is, well, demote an instance to
> > slave. Why would you want to stop it?
> 
> Because PostgreSQL cannot transit from Master to Slave.
> 
> > Of course, nothing's stopping you to that and I guess that pacemaker would be able to
> > deal with it eventually. But note that it'll expect the resource
> > to be in the Started state after demote.
> 
> It causes failing of monitor in spite of success of demote.
> 
> >
> >> I returned "$OCF_NOT_RUNNING" on demote as a trial,
> >> but it incremented a failcount.
> >
> > "$OCF_NOT_RUNNING" should be used only by the monitor operation.
> > It'll count as error with other operations.
> 
> get it.

Actually, Andrew told me on IRC about plans to support this:
<beekhof> oh, and start ops will be able to tell us a resource is master and demote that its stopped
<beekhof> if thats something you feel inclined to take advantage

So, a "start" could then return $OCF_RUNNING_MASTER to indicate that it
went straight into Master mode, and a "demote" would be able to indicate
it went straight into Stopped state by returning $OCF_NOT_RUNNING.

No idea when that will be available or in which release.

	Lars

-- 
: Lars Ellenberg
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