Comment 3 for bug 1695634

The only maybe relevant thing I can see is:

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index c8a4c22..d40ca77 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -1150,7 +1150,14 @@ class ComputeManager(manager.Manager):
         finally:
             if CONF.defer_iptables_apply:
                 self.driver.filter_defer_apply_off()
- self._update_scheduler_instance_info(context, instances)
+ if instances:
+ # We only send the instance info to the scheduler on startup
+ # if there is anything to send, otherwise this host might
+ # not be mapped yet in a cell and the scheduler may have
+ # issues dealing with the information. Later changes to
+ # instances on this host will update the scheduler, or the
+ # _sync_scheduler_instance_info periodic task will.
+ self._update_scheduler_instance_info(context, instances)

Perhaps this is causing there to be a delay somewhere and nova is expecting an eventual consistency of some sort - but the shade test here is happening before whatever has woken up and registered something with the cell?