The CRUSH Map shows a toasty error, if connection to cluster fails

2017-09-29 17:22:51,683 30413 mod_wsgi ERROR exception#custom_handler - Internal Server Error: None
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/rest_framework/views.py", line 400, in dispatch
    response = handler(request, *args, **kwargs)
  File "/srv/openattic/backend/ceph/restapi.py", line 75, in crushmap
    data = CrushmapVersionSerializer(self.get_object().get_crushmap(), many=False, read_only=True).data
  File "/srv/openattic/backend/ceph/models.py", line 173, in get_crushmap
    return CrushmapVersion.objects.get()
  File "/usr/lib/python2.7/site-packages/django/db/models/manager.py", line 151, in get
    return self.get_queryset().get(*args, **kwargs)
  File "/srv/openattic/backend/nodb/models.py", line 210, in get
    num = len(filtered_data)
  File "/srv/openattic/backend/nodb/models.py", line 181, in __len__
    return len(self._filtered_data)
  File "/usr/lib/python2.7/site-packages/django/utils/functional.py", line 49, in __get__
    res = instance.__dict__[self.func.__name__] = self.func(instance)
  File "/srv/openattic/backend/nodb/models.py", line 164, in _filtered_data
    filtered = [obj for obj in self._data()
  File "/srv/openattic/backend/nodb/models.py", line 93, in _data
    objects = self.model.get_all_objects(context, query=self._query)
  File "/srv/openattic/backend/ceph/models.py", line 1001, in get_all_objects
    crushmap = RadosMixin.mon_api(fsid).osd_crush_dump()
  File "/srv/openattic/backend/ceph/librados.py", line 484, in osd_crush_dump
    return self._call_mon_command('osd crush dump')
  File "/srv/openattic/backend/ceph/librados.py", line 990, in _call_mon_command
    timeout)
  File "/srv/openattic/backend/ceph/librados.py", line 377, in call_librados
    client = clients[fsid]
  File "/srv/openattic/backend/ceph/librados.py", line 362, in __getitem__
    self.instances[fsid] = ClusterConf.from_fsid(fsid).client
  File "/usr/lib/python2.7/site-packages/django/utils/functional.py", line 49, in __get__
    res = instance.__dict__[self.func.__name__] = self.func(instance)
  File "/srv/openattic/backend/ceph/librados.py", line 158, in client
    return Client(self.file_path, self.keyring)
  File "/srv/openattic/backend/ceph/librados.py", line 234, in __init__
    self.connect(self._conf_file)
  File "/srv/openattic/backend/ceph/librados.py", line 249, in connect
    self._cluster.connect()
  File "rados.pyx", line 875, in rados.Rados.connect (/home/abuild/rpmbuild/BUILD/ceph-12.2.0+git.1506009682.0e5b4307f3/build/src/pybind/rados/pyrex/rados.c:10952)
ObjectNotFound: [errno 2] error connecting to the cluster