Need support for live-migration/ssh-key management across different nova-compute applications

[Drew Freiberger]

There is currently a limitation that live-migration ssh trust is only setup between units in the same nova-compute application. This prevents migration of instances between two separately configured nova-compute applications as I understand it.

When performing cloud expansions, there are many times where the ephemeral-device is a different path from the original nodes due to changing storage and server geometries over several years between cloud inception and cloud expansion.

I'd like to request a relation interface that syncs ssh host keys and nova user keys across different nova-compute applications in order to allow for live-migration between older and newer configured applications that are intended to host the same VMs.