This change tightens the validation around the attachment
update API to ensure that it can only be called if the source
volume has a non empty migration status.
That means it will only accept a request to swap the volume if
it is the result of a cinder volume migration.
This change is being made to prevent the instance domain
XML from getting out of sync with the nova BDM records
and cinder connection info. In the future support for direct
swap volume actions can be re-added if and only if the
nova libvirt driver is updated to correctly modify the domain.
The libvirt driver is the only driver that supported this API
outside of a cinder orchestrated swap volume.
By allowing the domain XML and BDMs to get out of sync
if an admin later live-migrates the VM the host path will not be
modified for the destination host. Normally this results in a live
migration failure which often prompts the admin to cold migrate instead.
however if the source device path exists on the destination the migration
will proceed. This can lead to 2 VMs using the same host block device.
At best this will cause a crash or data corruption.
At worst it will allow one guest to access the data of another.
Prior to this change there was an explicit warning in nova API ref
stating that humans should never call this API because it can lead
to this situation. Now it considered a hard error due to the
security implications.
Closes-Bug: #2112187
Depends-on: https://review.opendev.org/c/openstack/tempest/+/957753
Change-Id: I439338bd2f27ccd65a436d18c8cbc9c3127ee612
Signed-off-by: Sean Mooney <work@seanmooney.info>
Sean Mooney
93c0f9bc74