[Users] Should host reboot trigger migration?

[Doron Fediuck]

----- Original Message -----
> From: "Dan Kenigsberg" <danken at redhat.com>
> To: "Mario Giammarco" <mgiammarco at gmail.com>, doron at redhat.com
> Cc: users at ovirt.org
> Sent: Saturday, October 12, 2013 11:28:18 PM
> Subject: Re: [Users] Should host reboot trigger migration?
> 
> On Sat, Oct 12, 2013 at 05:14:45PM +0000, Mario Giammarco wrote:
> > Hello,
> > I have a two hosts ovirt cluster.
> > I rebooted one of the hoping to see the migration of vm on other host.
> > But it does not happen and so vm are brutally shutdownd.
> > 
> > Is auto migration supported? Where can I enable it?
> 
> I am afraid that we have no means for a host to inform Engine about an
> immanent reboot.
> 
> A scheduled reboot of a host should begin in moving it to "maintenance"
> in Engine.
> 
> However, what you are looking for makes a nice SLA feature, maybe Doron
> has plans for implementing something similar.
> 
> Dan.

Hi Mario.

As Dan explained, in managed data centers a host is first put into maintenance
mode when needed. This ensures any critical resources are handled properly,
and in this case the VMs are migrated if needed.

Additionally, auto migration was meant to handle highly-available VMs, when
the host is properly configured with power management. In such a case if the
connection to this host is lost, it will be restarted by the engine and then
the VM will be resumed on a different host.

Plain reboot is not a common practice in such a setup and therefor unhandled
so far. We do have thoughts on allowing a shadow VM for fault tolerance in the
future, so if you're interested let us know.

Thanks for the feedback,
Doron