On Tue, Aug 1, 2017 at 4:25 PM, Numan Siddique <nusid...@redhat.com> wrote:
> > > 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 ? > Given that SB DB ovsdb-server would assign the lock, it has to be a tcp connection. Sorry for the confusion. > 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
