When only running volume migrations, a zone migration
strategy audit without setting compute_nodes should work.
Before this change, an audit with defined storage_pools,
no compute_nodes parameters, and with_attached_volume is set to True
would trigger the migration of the instances attached to the volumes
being migrated.
This patch decouples instance and volume migrations unless the user
explicitely asks for both. When migrating attached volumes, the zone
migration strategy will check for which instances should be migrated
according to the audit parameters, and if the instance the volume is
attached to can be migrated, it will be just after the volume.
On the other hand, when the attached instances should not be migrated
according to user input, only the volumes will be migrated.
In an audit that migrates instnaces but not volumes, the
with_attached_volume parameter will continue doing nothing.
Closes-Bug: 2111429
Change-Id: If641af77ba368946398f9860c537a639d1053f69
Signed-off-by: jgilaber <jgilaber@redhat.com>
c2ad4b28da