Comment 12 for bug 1456073

Nova already has a method to set up networks on the destination host during the pre -live migration phase. See the pre_live_migrate() method in nova/compute/manager.py.

For neutron the pre_live_migrate() method is empty - but for nova networking it is used to setup the networks on the destination in advance of the migration. I think this method should be defined to call neutron to set up the networks as you want for DVR. So long as this is not a very long operation it woud be appropriate for nova to block at this point waiting for the network setup to be done.

If the pre_live_migration() method throws an exception the migration is roled back. I think that would provide all that is needed for the nova side.