Re: Fwd: Postgres HA - pacemaker RA do not support auto failback

On Mon, 12 Aug 2019, 18:54 Adrien Nayrat, <adrien(dot)nayrat(at)anayrat(dot)info>
wrote:

> On 8/12/19 2:57 PM, Shital A wrote:
> >
> >
> > Hello,
> >
> > Postgres version : 9.6
> > OS:Rhel 7.6
> >
> > We are working on HA setup for postgres cluster of two nodes in
> active-passive
> > mode.
> >
> > Installed:
> > Pacemaker 1.1.19
> > Corosync 2.4.3
> >
> > The pacemaker agent with this installation doesn't support automatic
> failback.
> > What I mean by that is explained below:
> > 1. Cluster is setup like A - B with A as master.
> > 2. Kill services on A, node B will come up as master.
> > 3. node A is ready to join the cluster, we have to delete the lock file
> it
> > creates on any one of the node and execute the cleanup command to get
> the node
> > back as standby
> >
> > Step 3 is manual so HA is not achieved in real sense.
> >
> > Please help to check:
> > 1. Is there any version of the resouce agent which supports automatic
> failback?
> > To avoid generation of lock file and deleting it.
> >
> > 2. If there is no such support, what checks should be added in pgsql RA
> to achieve
> >
> > Please suggest.
> > Thanks.
> >
>
> Hello,
>
> Which RA did you use? AFAIK there is two RA :
> - pgsql :
> https://github.com/ClusterLabs/resource-agents/blob/master/heartbeat/pgsql
> - PAF : http://clusterlabs.github.io/PAF/ (Which is different from pgsql
> RA :
> http://clusterlabs.github.io/PAF/FAQ.html#why-new-ra-for-postgresql)
>
> If I am right, PAF should handle the case when there no need to perform
> pgrewind
> (if the old master is not too advanced in the transaction log).
>
> Regards,
>
> --
> Adrien NAYRAT
> https://blog.anayrat.info

Hello

We are using the pgsql RA installed with pacemaker.

Is PAF recommended over pgsql?

Has anyone changed pgsql to handle the lock file and other cases that might
not have been handled?

Please advise.

Thanks.