[Pacemaker] Location constraints when dealing with multi-site clusters

Dejan Muhamedagic dejanmm at fastmail.fm
Tue May 27 12:16:49 EDT 2014


On Mon, May 26, 2014 at 02:56:18PM +0200, Christian Ciach wrote:
> Hello,
> I am dealing with a three-node multi-site cluster using pacemaker and
> corosync. The third node is a quorum-only node.
> The three nodes form a single cluster and are connected using corosync over
> the internet (using VPN tunnels). Of cource, using corosync over the
> internet and using a third node with the full corosync/pacemaker stack
> installed doesn't seem to be the ideal solution.
> So I took a look at the booth daemon, which, at first glance, seems like a
> better alternative. Unfortunately, because I would have to split my single
> cluster into two local ones, I don't see a way to still use location
> constraints for my resources. For my use case it is important to always
> migrate the master resource based on a calculated score. This works great
> with single clusters.
> Am I missing something or is this indeed a disadvantage when using booth?

booth has been designed with quite a different purpose in mind.
A ticket has only two states* and depending on that a resource
may be allowed to start (or promote) on the cluster or not. A
ticket fails over to another site in case the existing site is
not reachable anymore. Or the user defined external program
fails. Perhaps you could fiddle with the latter, but I doubt
that it'd be of any use in the end. So, the short answer is that
booth isn't meant for what you want to achieve here.



*) Apart from granted/revoked there's also standby, but that's
not relevant here.

> Best regards,
> Christian

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