Comment 13 for bug 1452641

This manifested itself again on a Mitaka cloud, we had moved the Ceph mons and existing, running, instances were fine, fresh new instances were fine, but when we stopped instances via nova, then started them again, they failed to start. Editing the xml didn't fix anything of course because Nova overwrite the xml on machine start.

I ended up fixing the nova db:

update block_device_mapping set connection_info = replace(connection_info, '"a.b.c.d", "a.b.c.e", "a.b.c.f"', '"a.b.c.foo", "a.b.c.bar", "a.b.c.baz"') where connection_info like '%a.b.c.d%'
 and deleted_at is NULL;

The select query could have been better (don't copy me!) but you get the point.

Subscribing field-high because this is something that will continue to bite folks every time ceph-mon hosts are moved around.