[ClusterLabs] Problems with pacemaker

[Ken Gaillot]

On Thu, 2017-11-16 at 10:27 +0100, Salvatore D'Angelo wrote:
> Hi All, 
> 
> I am working on a PostgreSQL cluster managed using Pacemaker and
> Corosync. 
> The cluster is composed by three nodes: Master, Sync and Async. 
> Currently my cluster uses PostgreSQL 9.4.9 and I am going to upgrade
> my environments to 9.6.3. 
> 
> My upgrade procedure uses the following steps: 
> 
> 1. install 9.6.3 binaries on all the three nodes 
> 2. crm node standby of all the three nodes 

Another option would be to put the cluster into maintenance mode at
this step instead of standby. The cluster would continue monitoring
pgsql and reporting failures, but wouldn't do anything about them.

Then I think you could replace steps 7-11 with: start postgres on all
nodes, wait for the monitors to come back OK, then take the cluster out
of maintenance mode.

> 3. create new data directory on all the three nodes 
> 4. only on master node do initdb on data directory 
> 5. pg_upgrade from old to the new directory 
> 6. update postgresql.conf file 
> 7. start postgres with pg_ctl command 
> 8. stop postgres with pg_ctl command 
> 9. crm node online <master node> 
> 
> on the others two nodes: 
> 10. pg_base_backup to align slave node with master 
> 11. crm node online <slave node> 
> 
> Now I have two questions: 
> 1. In order to have the master working properly I needed step 7 and 8
> in order to let master recognize the status of the cluster before the
> upgrade and let it recognize the others node and go in hot standby
> mode. Is this start/sto really required or there is another way to
> have master start from the status before the upgrade? 
> 
> 2. On test environment this procedure works fine. In production, two
> times happened that when I start nodes in step 9 the slaves start as
> well. Is this possible? In which case this could happen? 
> 
> Salvatore D'Angelo
> Advisory Software  Engineer - IBM Cloud
> IBM Rome Software Lab
> Via Sciangai 53, 00144 Roma
> Phone +39-347-432-8059
> 
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-- 
Ken Gaillot <kgaillot at redhat.com>