----- Original Message ----- > From: "mots" <[email protected]> > To: "Barak Azulay" <[email protected]> > Cc: [email protected] > Sent: Tuesday, November 18, 2014 1:17:49 AM > Subject: AW: [ovirt-users] Fake power management? > > -----Ursprüngliche Nachricht----- > > > Von:Barak Azulay <[email protected] <mailto:[email protected]> > > > Gesendet: Mon 17 November 2014 23:30 > > An: Patrick Lottenbach <[email protected] <mailto:[email protected]> > > > CC: [email protected] <mailto:[email protected]> > > Betreff: Re: AW: [ovirt-users] Fake power management? > > > > Well you can hack the solution in the form of replacing the fencing master > > script to always return success (Eli can help you with that), > > and define an imaginary fencing device on each host ... meaning that the > > fencing command will always succeeds. > > > > This sounds interesting. It's exactly what I need. > > > But this may be risky ... as you might end up with the same VM running on 2 > > hosts. > > As I see it, this would only happen if someone unplugs the network interface. > I know this is a way to break the cluster. If someone unplugs the interface, > then everything gets started twice anyways thanks to pacemaker being > configured to ignore the lack of quorum and it would look silly in front of > the customer. > > > And one last note ... when you disconnect one of the hosts in the demo you > > mentioned, I think you'll be better to disconnect the host that does not > > run the engine ... > > It just gets restarted on the remaining node and resumes operation. It even > remembers which guests ran on which host. > That part is really safe. The storage is configured to only report data as > written when the write operation has finished on all (currently online) > nodes, disk write caches are turned off in lvm.conf. PostreSQL is resilient > enough to survive a crash like this. > > Or am I missing something that might break?
Let me know if we missed something This is an interesting demo ;-) > > > Barak > > mots > > > > > ----- Original Message ----- > > > From: "mots" <[email protected] <mailto:[email protected]> > > > > To: "Barak Azulay" <[email protected] <mailto:[email protected]> > > > > Cc: [email protected] <mailto:[email protected]> > > > Sent: Monday, November 17, 2014 12:58:20 PM > > > Subject: AW: [ovirt-users] Fake power management? > > > > > > Yes, pacemaker manages the engine. That part is working fine, the engine > > > restarts on the remaining node without problems. > > > It's just that the guests don't come back up until the powered down node > > > has > > > been fenced manually. > > > > > > -----Ursprüngliche Nachricht----- > > > > Von:Barak Azulay <[email protected] <mailto:[email protected]> > > > > <mailto:[email protected] <mailto:[email protected]> > > > > > > Gesendet: Mon 17 November 2014 11:35 > > > > An: Patrick Lottenbach <[email protected] <mailto:[email protected]> > > > > <mailto:[email protected] <mailto:[email protected]> > > > > > > CC: [email protected] <mailto:[email protected]> <mailto:[email protected] > > > > <mailto:[email protected]> > > > > > Betreff: Re: [ovirt-users] Fake power management? > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > From: "mots" <[email protected] <mailto:[email protected]> > > > > > <mailto:[email protected] <mailto:[email protected]> > > > > > > > To: [email protected] <mailto:[email protected]> <mailto:[email protected] > > > > > <mailto:[email protected]> > > > > > > Sent: Friday, November 14, 2014 4:54:08 PM > > > > > Subject: [ovirt-users] Fake power management? > > > > > > > > > > Fake power management? Hello, > > > > > > > > > > I'm building a small demonstration system for our sales team to take > > > > > to a > > > > > customer so that they can show them our solutions. > > > > > Hardware: Two Intel NUC's, a 4 port switch and a laptop. > > > > > Engine: Runs as a VM on one of the NUCs, which one it runs on is > > > > > determined > > > > > by pacemaker. > > > > > Storage: Also managed by pacemaker, it's drbd backed and accessed > > > > > with > > > > > iscsi. > > > > > oVirt version: 3.5 > > > > > OS: CentOS 6.6 > > > > > > > > > > The idea is to have our sales representative (or the potential > > > > > customer > > > > > himself) randomly pull the plug on one of the NUCs to show that the > > > > > system > > > > > stays operational when part of the hardware fails. > > > > > > > > I assume you are aware that the engine might fence the node it is > > > > running > > > > on ... > > > > Or do you use pacemaker to run the engine as well ? > > > > > > > > > My problem is that I don't have any way to implement power > > > > > management, so > > > > > the > > > > > Engine can't fence nodes and won't restart guests that were running > > > > > on > > > > > the > > > > > node which lost power. In pacemaker I can just configure fencing over > > > > > SSH > > > > > or > > > > > even disable the requirement to do so completely. Is there something > > > > > similar > > > > > for oVirt, so that the Engine will consider a node which it can't > > > > > connect > > > > > to > > > > > to be powered down? > > > > > > > > > > Regards, > > > > > > > > > > mots > > > > > > > > > > _______________________________________________ > > > > > Users mailing list > > > > > [email protected] <mailto:[email protected]> <mailto:[email protected] > > > > > <mailto:[email protected]> > > > > > > http://lists.ovirt.org/mailman/listinfo/users > > > > > <http://lists.ovirt.org/mailman/listinfo/users> > > > > > <" target="_blank">http://lists.ovirt.org/mailman/listinfo/users> > > > > > <http://lists.ovirt.org/mailman/listinfo/users> ; > > > > > > > > > > > > > > > > > > > _______________________________________________ Users mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/users
