[ClusterLabs] Can a two node cluster start with only one node?

[john tillman]

Thanks, Ken.  I apologize for this truncated email.  It was sent by
mistake.  I have sent another with the completed thought.

Again, sorry for the false start.

-John


> On Wed, 2022-04-20 at 12:09 -0400, john tillman wrote:
>> Here's the scenario:
>>    I have a two node cluster setup. (details to follow)
>>    I start with both nodes booted.
>>    I can reboot the active node and the resources move.
>>
>
> By default, corosync's two_node mode enables wait_for_all, which means
> that when a node first starts up, it has to see the other node at least
> once before it will claim to have quorum. This is the only safe mode of
> operation, otherwise two nodes that get severed from each other and
> then reboot will both claim quorum.
>
> However you can override that by setting wait_for_all to false in the
> corosync configuration. This is mainly useful when you are
> intentionally and manually bringing the cluster down and want to bring
> up a single node. Once the node is up you can set wait_for_all back to
> true for safety, so if it reboots unexpectedly it will require manual
> intervention again to get going.
> --
> Ken Gaillot <kgaillot at redhat.com>
>
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