[2.0a1] Service tracking of rackd broken rack registration

[Blake Rouse]

2016-03-12 01:53:59 [-] Failed to register rack controller '4y3h7p' into the database. Connection has been dropped.
 Traceback (most recent call last):
   File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 588, in _runCallbacks
     current.result = callback(current.result, *args, **kw)
   File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1184, in gotResult
     _inlineCallbacks(r, g, deferred)
   File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1128, in _inlineCallbacks
     result = g.send(result)
   File "/usr/lib/python3/dist-packages/maasserver/rpc/regionservice.py", line 561, in register
     log.err(exc, msg)
 --- <exception caught here> ---
   File "/usr/lib/python3/dist-packages/maasserver/rpc/regionservice.py", line 534, in register
     registerConnection, rack_controller, self.host)
   File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 246, in inContext
     result = inContext.theWork()
   File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 262, in <lambda>
     inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
   File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 118, in callWithContext
     return self.currentContext().callWithContext(ctx, func, *args, **kw)
   File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 81, in callWithContext
     return func(*args,**kw)
   File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 448, in call_within_transaction
     return func_outside_txn(*args, **kwargs)
   File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 275, in retrier
     return func(*args, **kwargs)
   File "/usr/lib/python3.5/contextlib.py", line 30, in inner
     return func(*args, **kwds)
   File "/usr/lib/python3/dist-packages/maasserver/rpc/regionservice.py", line 459, in registerConnection
     endpoint=endpoint, rack_controller=rack_controller)
   File "/usr/lib/python3/dist-packages/django/db/models/manager.py", line 127, in manager_method
     return getattr(self.get_queryset(), name)(*args, **kwargs)
   File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 407, in get_or_create
     return self._create_object_from_params(lookup, params)
   File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 439, in _create_object_from_params
     obj = self.create(**params)
   File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 348, in create
     obj.save(force_insert=True, using=self.db)
   File "/usr/lib/python3/dist-packages/maasserver/models/cleansave.py", line 29, in save
     return super(CleanSave, self).save(*args, **kwargs)
   File "/usr/lib/python3/dist-packages/maasserver/models/timestampedmodel.py", line 64, in save
     return super(TimestampedModel, self).save(*args, **kwargs)
   File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 734, in save
     force_update=force_update, update_fields=update_fields)
   File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 771, in save_base
     update_fields=update_fields, raw=raw, using=using)
   File "/usr/lib/python3/dist-packages/django/dispatch/dispatcher.py", line 189, in send
     response = receiver(signal=self, sender=sender, **named)
   File "/usr/lib/python3/dist-packages/maasserver/models/signals/services.py", line 27, in update_rackd_status
     instance.rack_controller.update_rackd_status()
   File "/usr/lib/python3/dist-packages/maasserver/models/node.py", line 3493, in update_rackd_status
     dead_regions + len(missing_regions)))
   File "/usr/lib/python3/dist-packages/maasserver/models/service.py", line 96, in update_service_for
     service = self.get(node=node, name=service)
   File "/usr/lib/python3/dist-packages/django/db/models/manager.py", line 127, in manager_method
     return getattr(self.get_queryset(), name)(*args, **kwargs)
   File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 334, in get
     self.model._meta.object_name
 maasserver.models.service.DoesNotExist: Service matching query does not exist.