GlusterFS support

[rgooch]

@cviecco I'm thinking about some implementation questions. I'll put each one in a separate comment so that each can be replied to independently.

First, should VM owners specify which Gluster/volume to use for the backing store, or should they just specify that they want any GlusterFs volume?

[rgooch]

@cviecco Secondly, should a common set of credentials be distributed to all Hypervisors, or should they be partitioned so that different sets of credentials are distributed to different groups of Hypervisors?

[cviecco]

I am assuming each hypervisor will have its own set of TLS certs. But I could be convinced otherwise

[rgooch]

No, the Hypervisors share the same client certificate. It's not a very powerful certificate. These are the permitted methods:
Hypervisor.PrepareVmForMigration ImageServer.CheckDirectory ImageServer.FindLatestImage ImageServer.GetImage ObjectServer.GetObjects