Compute CDM should have hypervisor layer

[Hidekazu Nakamura]

Currently Compute CDM has two layers: ComputeNode and Instance.
Uuid of ComputeNode is compute node name, Hostname of ComputeNode is hypervisor_hostname.
If we use libvirt driver, uuid is the same as hypervisor_hostname,
But those are differerent and compute node may have multi hypervisors if we use the VMware vCenter driver[1].

Compute CDM should have three layers: ComputeNode, Hypervisor and Instance.

[1] https://docs.openstack.org/nova/pike/admin/configuration/hypervisor-vmware.html

[Alexander Chadin (joker946)]

I think we need additional blueprint since there will be architecture changes.