Following from http://projects.theforeman.org/issues/4337 , Openstack compute resources should have access to volumes.

• New hosts should be able to be provisioned using block device mapping
• Block device mapping should support ephemeral disks
• Host#view should show volumes attached to it if its an Openstack VM.
• Openstack Compute Resources should show volumes.

boot-volume, swap, and snapshots will be supported once they are in Fog, but other tickets will cover that.

More info here https://wiki.openstack.org/wiki/BlockDeviceConfig