Re: [ovirt-users] Fake power management?

From: "mots" <mots(a)nepu.moe&gt; To: "Eli Mesika" <emesika(a)redhat.com&gt; Cc: users(a)ovirt.org Sent: Sunday, November 16, 2014 12:53:53 PM Subject: AW: [ovirt-users] Fake power management? Hello Eli, If I replace "/usr/bin/vdsm-tool service-restart vdsmd" with "echo b > /proc/sysrc-trigger", will the Engine consider the node to be fenced and restart the VMs that were running on it on another node? I don't see a mechanism to inform the engine that this was a "hard" fencing operation and that it's save to restart the guests.

Regards, mots   -----Ursprüngliche Nachricht----- > Von:Eli Mesika <emesika(a)redhat.com <mailto:emesika@redhat.com> > > Gesendet: Son 16 November 2014 03:00 > An: Patrick Lottenbach <pl(a)a-bot.ch <mailto:pl@a-bot.ch> > > CC: users(a)ovirt.org <mailto:users@ovirt.org> > Betreff: Re: [ovirt-users] Fake power management? > > > > ----- Original Message ----- > > From: "Sandro Bonazzola" <sbonazzo(a)redhat.com > > <mailto:sbonazzo@redhat.com> > > > To: "mots" <mots(a)nepu.moe <mailto:mots@nepu.moe> >, users(a)ovirt.org > > <mailto:users@ovirt.org> > > Sent: Friday, November 14, 2014 5:15:25 PM > > Subject: Re: [ovirt-users] Fake power management? > > > > Il 14/11/2014 15:54, mots ha scritto: > > > 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 > > > > Just for curiosity, any reason for using pacemaker instead on oVirt > > Hosted > > Engine solution? > > > > > > > > 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. > > > 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? > > Well, we are thinking of adding such ability (Fake power management) mainly > for testing purpose... > Meanwhile, I think I have a work-around that may help you. > > When we have a connectivity issue with a node, we first try (after a grace > period) to restart its VDSM via SSH > this is always done before the hard-fencing (restart via the PM card) and > can be done no matter if the host has PM configured or not. > So basically when a connectivity issue is found, you can custom the SSH > command that restarts VDSM to do whatever you want, even a script or a > power-down command > > look at the result of > > > psql -U engine -c "select * from vdc_options where option_name ilike > > 'SshSoftFencingCommand'" engine > > option_id | option_name | option_value > | version > -----------+-----------------------+------------------------------------------+--------- > 558 | SshSoftFencingCommand | service vdsmd restart > | 3.0 > 559 | SshSoftFencingCommand | service vdsmd restart > | 3.1 > 560 | SshSoftFencingCommand | service vdsmd restart > | 3.2 > 561 | SshSoftFencingCommand | /usr/bin/vdsm-tool service-restart > vdsmd | 3.3 > 562 | SshSoftFencingCommand | /usr/bin/vdsm-tool service-restart > vdsmd | 3.4 > 563 | SshSoftFencingCommand | /usr/bin/vdsm-tool service-restart > vdsmd | 3.5 > > > Please note: > > 1) change only the value that match your cluster version > 2) restart engine so change can take place > 3) restore to default value again after you are done > > Does this may be useful for you ? > > > > > > > > > Regards, > > > > > > mots > > > > > > > > > _______________________________________________ > > > Users mailing list > > > Users(a)ovirt.org <mailto:Users@ovirt.org> > > > http://lists.ovirt.org/mailman/listinfo/users > > > <http://lists.ovirt.org/mailman/listinfo/users> > > > > > > > > > -- > > Sandro Bonazzola > > Better technology. Faster innovation. Powered by community collaboration. > > See how it works at redhat.com > > _______________________________________________ > > Users mailing list > > Users(a)ovirt.org <mailto:Users@ovirt.org> > > http://lists.ovirt.org/mailman/listinfo/users > > <http://lists.ovirt.org/mailman/listinfo/users> > > >