On Tue, Aug 1, 2017 at 5:00 AM, Han Zhou <zhou...@gmail.com> wrote: > On Mon, Jul 31, 2017 at 1:53 PM, Russell Bryant <russ...@ovn.org> 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. > > >
In the case of Pacemaker, the pacemaker OCF resource script (ovndb-servers.ocf) starts the ovn-northd on the master node if manage_northd is set to true and this is the approach tripleo has taken. ovn-northd uses the unix sockets to communicate to the NB and SB db servers. With the suggested approach, ovn-northd would be using tcp connection to communicate to the db servers ? Thanks Numan > 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. > > > > This is crude, and obviously we would want to distribute work among > > ovn-northd instances eventually, but does this sound like an > > improvement over requiring something like Pacemaker? > > > Russell, this sounds very good. I think it is better than Pacemaker. I > would still call it active-standby though. The standby is hot-standby, not > cold-standby. > > It seems the change would be having the active one updating <timestamp, > northd hostname> periodically to southbound DB, so that other northd will > know if it is still alive, and otherwise taking over by updating the > <timestamp, northd hostname>. Is this correct? > > _______________________________________________ > dev mailing list > d...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev