If root disk source refers to a storage pool, then it is supposed to be supported on any provider that can provision block device storage which can be mounted as the root disk of an instance.
The doc is referring to the case where root disk source is not a storage pool name but rather a provider specific datastore or such.
The doc is not quite correct.
If root disk source refers to a storage pool, then it is supposed to be supported on any provider that can provision block device storage which can be mounted as the root disk of an instance.
The doc is referring to the case where root disk source is not a storage pool name but rather a provider specific datastore or such.