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

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