[openstack-dev] blueprint proposal nova-compute fencing for HA ?

Leen Besselink ubuntu at consolejunkie.net
Tue Apr 23 07:31:40 UTC 2013

> I was only talking about the fencing off a compute node part, since
> that's what you started the thread with.  :-)

I know I'm going in circles, just trying to get a feel for the best way to handle it.

> Presumably you would still use nova APIs that already exist to move the
> instances elsewhere.  An 'evacuate' API went in to grizzly for this.
> https://blueprints.launchpad.net/nova/+spec/rebuild-for-ha

So when any node fails in a Pacemaker cluster, you fence the node, tell OpenStack about the
failed node and call evacuate for all the instances. The scheduler will just place them anywhere
it pleases.

(there is already a blueprint for evacuate to call the scheduler and even an other for handling a whole node)

So, yeah, maybe that is enough.

I guess I was hoping all machines would be the same. Now I'll need to make clusters. To OpenStack
they will still all look the same I guess.

But it will work with existing tested code, that is also important.

So no blueprint for fencing.

Thank you for the discussion.

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