Originated from 17.1 BZ: https://bugzilla.redhat.com/show_bug.cgi?id=2318251

When we discussed this on the triage call and speculated the request might be related to a VMware out-of-tree driver feature where volume encryption can be requested via an extra_spec, perhaps vmware:storage_profile [1]?

Either way, it should be relatively simple for to add a flavor extra_spec for Cinder volume_type and then pass the value over to Cinder when we create the volume.

[1] https://docs.vmware.com/en/VMware-Integrated-OpenStack/5.1/com.vmware.openstack.admin.doc/GUID-2E7680D5-6F62-4775-BA25-5F4924517E65.html