live_migration does not perform vif unplugging

[dan wendlandt]

Migrated a VM with the command:

sudo nova-manage vm live_migration i-00000011 host2

If we are migrating from host1 to host2, the network devices representing the VM VIF on host1 are not properly destroyed.
This ends up confusing Quantum, as the VM appears to both be in the old and new location simultaneously, leading to incorrect behavior.

Seems like the underlying problem is that vif unplugging usually happens in the driver.destroy() call in the virt layer. However, in the case of live migration (i.e., non block migration), destroy is not called, meaning we have to unplug the vifs explicitly.

[dan wendlandt (danwent)]

Fix available for review: https://review.openstack.org/#change,2253,patchset=1

(isn't jenkins supposed to do this automatically? perhaps my syntax in the commit message is wrong?)

[Thierry Carrez (ttx)]

That's bug 860779 -- I'm on it :)

[Openstack Gerrit (openstack-gerrit)]

Reviewed: https://review.openstack.org/2253
Committed: http://github.com/openstack/nova/commit/6b6633521c57422dfcdd1c0fbd8004c01bbe99cc
Submitter: Jenkins
Branch: master

 status fixcommitted
 done

commit 6b6633521c57422dfcdd1c0fbd8004c01bbe99cc
Author: Dan Wendlandt <email address hidden>
Date: Mon Dec 12 10:34:33 2011 -0800

    bug 899767: fix vif-plugging with live migration

    Expose vif_unplug method in virt layer, as the compute manager has to
    explicitly call it on during live migration, so that network devices are
    torn down even if the disk image is not.

    Change-Id: Iae88c72f4fd2c7c097c23ef9e5f8fd392052f73e