[libvirt] [PATCH]: Implement Qemu/KVM live migration

Daniel Veillard veillard at redhat.com
Wed Nov 12 08:29:12 UTC 2008

On Tue, Nov 11, 2008 at 10:11:40PM +0000, Daniel P. Berrange wrote:
> On Thu, Nov 06, 2008 at 03:10:29PM +0100, Chris Lalancette wrote:
> > All,
> >      Attached is a patch to implement Qemu/KVM live migration in libvirt.  Now
> > that upstream Qemu has settled on an interface that is friendly to libvirt (i.e.
> > one that doesn't block the monitor on -incoming), we can implement it here.
> > Note that the bulk of this patch was written by Rich Jones quite a while ago.
> > My hand in it has mostly been to forward port it to current libvirt CVS, tweak
> > it for the new Qemu style, and test it out with a recent KVM (kvm-78, in
> > particular).
> >      Note that there is a FIXME in the code.  When testing this out with kvm-78,
> > I found that if I let the source side kill the source VM immediately after the
> > "migrate" monitor command completed, the migration to the destination would
> > never complete.  This seems to be a bug in Qemu; the migrate monitor command
> > shouldn't return until the migrate is really, truly complete.  I'm posting this
> > now so I can get reviews, and start to address review comments while I try to
> > figure out what's going on with Qemu.  With my temporary hack of the sleep()
> > call in there, though, I was able to successfully live migrate an F-9 guest
> > between two machines.
> > 
> > Signed-off-by: Chris Lalancette <clalance at redhat.com>
> Now that the QEMU bug is fixed, I'm inclined to say we should commit this
> migration support - minus the sleep(5) of course. It is well overdue to
> have migration in the QEMU driver, and oVirt guys have sanity checked its
> implementation in their developemnt, so shouldn't be any surprises.

  Agreed, +1


Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
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