I'm hoping someone more learned can teach me. These two options sound very similar, and are thus very confusing. They are also both in the [DEFAULT] config option group, but defined in different places [1][2]. The help text for one says: "This option determines the availability zone to be used when it is not specified in the VM creation request." The help text for the other says: "Availability zone to use when user doesn't specify one. This option is used by the scheduler to determine which availability zone to place a new VM instance into if the user did not specify one at the time of VM boot request." It looks like one goes on the instance record itself, and the other goes into an aggregate metadata if the zone is specified for the aggregate. So while they sound the exact same, they are not? Or are they in the end? See how this is terrible? [1] https://github.com/openstack/nova/blob/5a556a720f5a7394cab4c84fa6202976c6190b23/nova/conf/availability_zone.py#L34 [2] https://github.com/openstack/nova/blob/5a556a720f5a7394cab4c84fa6202976c6190b23/nova/conf/compute.py#L49 -- Thanks, Matt