[ClusterLabs] Proper procedure for pacemaker RPM upgrades in active cluster

[Doug Cahill]

Hello,

I'm looking for some guidance on pacemaker RPM upgrades in a running
cluster environment.  I'm looking to automate the process of upgrading
the RPMs when we decide to plan an upgrade cycle for our clusters.

What I found is that during the RPM upgrade process the
pacemaker.x86_64 RPM will shutdown the pacemaker service.  My question
regarding this is...is it possible to upgrade the RPM component but
delay the restart part of the pacemaker service to a later time?  If
delaying the restart isn't possible, what is the preferred process for
people with existing clusters that require package upgrades?  Should I
upgrade the passive side first and then fail over to it and then
upgrade the other node which is now passive?  Does pacemaker support
running two nodes at different version levels during the upgrade
process?  Would enabling maintenance mode be appropriate/ideal for
this?

I last experienced this situation when I upgraded from 1.1.15 to
1.1.17.  Now that pacemaker 1.1.18 is available I'm looking to plan
this process a little better and would like to know what others use as
a procedure.

Basic software config:
CentOS 6.x (2.6.32-696.13.2.el6.x86_64)
pacemaker.x86_64       1.1.17-1.el6
corosync.x86_64        2.4.2-1.el6
crmsh.noarch           3.0.1_283-0
Two-node Cluster resources are configured for active/passive operation.

Thanks,
-Doug