Ubuntu – Assign public and private IP addresses for a KVM guest

I don't think you need to implement anything special here. You just need create your guests with two interfaces, and bridge them to the private and public interfaces of the hosts. So long as the interfaces on the hosts are named and mapped the same way, your guests should retain the same public and private IPs on the same networks when they are migrated.

I'm not sure if it's required, but this works for me:

• eth0-on-the-host: no ip on host, added to bridge
• vnet0: no ip on host, added to bridge
• bridge: ip of the host
• eth0-in-the-guest: ip of the guest

Note that most documentation suggests bringing the physical interface up with ip 0.0.0.0 after attaching it to the bridge.