[ovirt-users] Fake power management?

[Eli Mesika]

----- Original Message -----
> From: "mots" <mots at nepu.moe>
> To: "Eli Mesika" <emesika at redhat.com>
> Cc: users at 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.

We have a RFE for PM hooks but this was not done or get to a version plan yet 
So, the only way to release the VMs is to manually confirm that the node was rebooted ...

>  
> Regards,
> 
> mots
>  
> -----Ursprüngliche Nachricht-----
> > Von:Eli Mesika <emesika at redhat.com <mailto:emesika at redhat.com> >
> > Gesendet: Son 16 November 2014 03:00
> > An: Patrick Lottenbach <pl at a-bot.ch <mailto:pl at a-bot.ch> >
> > CC: users at ovirt.org <mailto:users at ovirt.org>
> > Betreff: Re: [ovirt-users] Fake power management?
> > 
> > 
> > 
> > ----- Original Message -----
> > > From: "Sandro Bonazzola" <sbonazzo at redhat.com
> > > <mailto:sbonazzo at redhat.com> >
> > > To: "mots" <mots at nepu.moe <mailto:mots at nepu.moe> >, users at ovirt.org
> > > <mailto:users at 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 at ovirt.org <mailto:Users at 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 at ovirt.org <mailto:Users at ovirt.org>
> > > http://lists.ovirt.org/mailman/listinfo/users
> > > <http://lists.ovirt.org/mailman/listinfo/users>
> > > 
> > 
> 
>