[ClusterLabs] how to setup single node cluster

[Andrei Borzenkov]

On 08.04.2021 09:26, d tbsky wrote:
> 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.


I do not know what "disaster recovery" configuration you have in mind,
but if you intend to use geo clustering fencing can speed up fail-over
so it is at least useful.

Even in single node cluster if resource failed to stop you are stuck -
you cannot actually do anything from that point without manual
intervention. Depending on configuration and requirements rebooting node
may be considered as an attempt to automatically "reset" cluster state.