[ovs-dev] [RFC] Basic active-active HA for ovn-northd

[Ben Pfaff]

On Mon, Jul 31, 2017 at 04:53:03PM -0400, Russell Bryant wrote:
> I wanted to share the idea before I code it to see if it makes sense.
> I imagine the patch would be small, though.
> 
> We currently provide HA for ovn-northd by using Pacemaker to ensure
> that ovn-northd is running only one time somewhere in a cluster.
> 
> What if we made ovn-northd acquire an OVSDB lock on the southbound
> database before it did any real work?  That way we could start
> multiple copies of ovn-northd in a cluster, but only one would be
> active at a time.

I think it's a reasonable approach.

It means that we'll have to make sure that clustered OVSDB, when it
becomes available, supports locks.  I hadn't yet decided whether locks
were important for that use case.  It sounds like they might be.