The Cinder 3.48 API provides a shared_targets and service_uuid
field in the volume resource which tells the caller whether or
not it should lock operations on that volume.
This change adds that logic to the DriverVolumeBlockDevice attach
and detach flows by first trying to get the volume at the 3.48
microversion and if that's not available, it simply falls back
to get the volume the same as before.
If 3.48 is available and the volume storage backend uses shared
targets, we synchronize the attach/detach operations using the
volume service_uuid, which is based on the storage backend and
is also configurable by the deployer on the Cinder side.
This is a nice to have protection for "normal" volumes but
is really needed for multiattach volumes to be detached safely.
See Cinder blueprint add-shared-targets-flag-to-volume for details.
Part of blueprint multi-attach-volume
Depends-On: I3c07cd8458d55535a71626ffaa8ca50deb3ca3dd
Change-Id: I5e96602184242fb9017c0434b445a3875f3b149a
1957f4d5a2