XenAPI pool based migration should error when not shared storage

[John Garbutt]

We should add a check to ensure the VM is on shared storage before trying to perform a pool migration.

See the TODO in virt/xenapi/vmops.py

[John Garbutt (johngarbutt)]

Edge case for a very infrequently used feature.
The new block migration code path shows much more promise.

[Bob Ball (bob-ball)]

Agreed. What are the requirements for block migration path before we can deprecate the pool migration path?

[John Garbutt (johngarbutt)]

Once block migration works with attached shared storage (NFS and iSCSI) I think we are good.

Raise this one at the summit though, we should see what others think.

[Tom Fifield (fifieldt)]

This TODO still exists:

            self._ensure_host_in_aggregate(ctxt, src)
            # TODO(johngarbutt) we currently assume
            # instance is on a SR shared with other destination
            # block migration work will be able to resolve this