[ClusterLabs] how to setup single node cluster

[d tbsky]

Reid Wahl <nwahl at redhat.com>
> I don't think we do require fencing for single-node clusters. (Anyone at Red Hat, feel free to comment.) I vaguely recall an internal mailing list or IRC conversation where we discussed this months ago, but I can't find it now. I've also checked our support policies documentation, and it's not mentioned in the "cluster size" doc or the "fencing" doc.

   since the cluster is 100% alive or 100% dead with single node, I
think fencing/quorum is not required. I am just curious what is the
usage case. since RedHat supports it, it must be useful in real
scenario.