Correct!

Stack trace added:

== cut ==
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server [req-1a597b99-3f7d-4ecd-be77-56e7c6d39d00 ab901f6a03e64d56a78bf9de0a382709 12c36e260d8e4bb2913965203b1b491f - default default] Exception during message handling: KeyError: (u'compute-21-ca-ymq-2.vexxhost.net', u'compute-21-ca-ymq-2.vexxhost.net')
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server Traceback (most recent call last):
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 160, in _process_incoming
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     res = self.dispatcher.dispatch(message)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 213, in dispatch
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     return self._do_dispatch(endpoint, method, ctxt, args)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 183, in _do_dispatch
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     result = func(ctxt, **new_args)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 232, in inner
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     return func(*args, **kwargs)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/manager.py", line 149, in select_destinations
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     alloc_reqs_by_rp_uuid, provider_summaries)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 88, in select_destinations
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     alloc_reqs_by_rp_uuid, provider_summaries)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 174, in _schedule
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     hosts = self._get_sorted_hosts(spec_obj, hosts, num)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 301, in _get_sorted_hosts
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     spec_obj, index)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/host_manager.py", line 589, in get_filtered_hosts
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     hosts, spec_obj, index)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/filters.py", line 69, in get_filtered_objects
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     list_objs = list(objs)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/nova/scheduler/host_manager.py", line 705, in <genexpr>
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server     return (self.host_state_map[host] for host in seen_nodes)
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server KeyError: (u'<server-hostname-removed>', u'<server-hostname-removed>')
2017-12-20 00:38:58.539 9457 ERROR oslo_messaging.rpc.server 
== cut ==