[ClusterLabs] Best-practices for changing networks settings in a cluster?

[Ken Gaillot]

On Mon, 2018-11-05 at 16:14 -0600, Ryan Thomas wrote:
> I have a two node cluster.  I restart the network after making
> changes to the network settings.  But, as soon as I restart the
> network I see that corosync/pacemaker are killed - causing resources
> to failover to the other node.  It looks like this is due to https://
> github.com/corosync/corosync/issues/348, this issue points that that
> corosync cannot handle downing an network interface with ifdown.  I'd
> like to avoid this, but I'd still like to be able to change the
> network settings. What is the best-practice for changing network
> settings on a cluster?  
> 
> The best workaround I can think of is to kill pacemaker on each
> process, make the network changes, and then restart pacemaker. 
> However, this seems pretty ugly and error-prone.  Is there  away to
> "pause" pacemaker for the whole cluster?  
> 
> Thanks in advance for your advice.
> Ryan

Hi,

Yes, maintenance mode is exactly for this purpose. You can set the
maintenance-mode cluster property to true, stop pacemaker and corosync,
update the network, start corosync and pacemaker, then set maintenance-
mode back to false.
-- 
Ken Gaillot <kgaillot at redhat.com>