Comment 4 for bug 1781286

OK looking at the stacktrace I see it's not the '_destroy_build_request' call that's blowing up on reschedule, it's the up-call to get the availability zone for the next chosen host from the list of alternates:

https://github.com/openstack/nova/blob/39b05ee9e34ae7e7c1854439f887588ec157bc69/nova/conductor/manager.py#L647

And if an AZ is not requested during server create, we are free to move the instance to another AZ during reschedule. So it seems we've fallen into a dreaded up-call hole here that needs to be tracked:

https://docs.openstack.org/nova/latest/user/cellsv2-layout.html#operations-requiring-upcalls