Comment 7 for bug 1383247

> Unfortunately, there is no pacemaker logs in the diagnostic snapshot so it is hard to investigate what happened.

check /var/log/remote/node*/rabbitmq-server.log for cluster reassembling events from pacemaker.
Other log from corosync and pacemaker are located under /var/log/node*/crmd , lrmd, attrd, cibadmin etc.