Tried upgrading my High availability cluster from 10.13.66-09 to 10.13.66-12 from Sysadmin.
The install of 12 failed causing a cluster failover.
2016-06-01 05:55:21: (10.13.66-12) Error running update script
2016-06-01 05:55:21: (10.13.66-12) Error running script. See /tmp/upgrade.log
I didn’t get a “High Availability detected, Enabled Maintenance Mode” message like I do usually when upgrading this way.
Now I am on 10.13.66-11.
tmp/upgrade.log:
The following upgrade errored at 1464774921
Loaded script from https://upgrades.freepbxdistro.org/stable/10.13.66/upgrade-10.13.66-12.sh
It exited with error code 143
Upgrade Started at 1464774803
There’s nothing in there, really. All it does is a ‘yum -y update asterisk1*’ and then ‘yum -y update’.
That can be simplified to ‘yum -y update’ 
The reason for it failing over will be shown when you run ‘pcs status’, and will say something like ‘asterisk was not started’.
Shouldn’t sysadmin have put the cluster into maintenance mode before upgrading?
It usually does that, but not this time.