Comment 4 for bug 1523506

As a newbie of OpenStack, I see the documentation[1] says that "Host aggregates can be regarded as a mechanism to further partition an availability zone". So it makes me believe that a host aggregate must belong to an availability zone in order to partition an AZ.

And what you said "the aggregate does not belong to an AZ at all if its AZ attribute is unset" confuses me.

Yes, the internal representation shows that 'node2' is actually belongs to the AZ named "az". But I think the scheduler behavior in step 3) should be treated as a bug. It should be fixed by returning error in executing `nova aggregate-update foo foo az`, or by updating the AZ field of aggregate "bar" to "az".

[1] http://docs.openstack.org/developer/nova/aggregates.html