From http://logs.openstack.org/periodic/periodic-tempest-devstack-vm-check-hourly/404/logs/screen-n-cond.txt
There are lots of these.
2012-11-29 19:17:30 29815 DEBUG nova.manager [-] Running periodic task ConductorManager.publish_service_capabilities periodic_tasks /opt/stack/nova/nova/manager.py:172
2012-11-29 19:17:34 29815 DEBUG nova.openstack.common.rpc.amqp [-] received {u'_context_roles': [], u'_msg_id': u'971480bb48574994aebce24c9d2c4e68', u'_context_quota_class': None, u'_context_request_id': u'req-5acd8b17-cd50-4e52-9877-be572eda2c3b', u'_context_service_catalog': None, u'_context_user_name': None, u'_context_auth_token': '<SANITIZED>', u'args': {u'instance_uuid': u'cec91bce-bfb5-4544-9bd6-1d43aff47b19'}, u'_context_instance_lock_checked': False, u'_context_project_name': None, u'_context_is_admin': True, u'version': u'1.2', u'_context_project_id': None, u'_context_timestamp': u'2012-11-29T19:17:27.770893', u'_context_read_deleted': u'no', u'_context_user_id': None, u'method': u'instance_get_by_uuid', u'_context_remote_address': None} _safe_log /opt/stack/nova/nova/openstack/common/rpc/common.py:195
2012-11-29 19:17:34 29815 DEBUG nova.openstack.common.rpc.amqp [-] unpacked context: {'project_name': None, 'user_id': None, 'roles': [], 'timestamp': u'2012-11-29T19:17:27.770893', 'auth_token': '<SANITIZED>', 'remote_address': None, 'quota_class': None, 'is_admin': True, 'service_catalog': None, 'request_id': u'req-5acd8b17-cd50-4e52-9877-be572eda2c3b', 'instance_lock_checked': False, 'project_id': None, 'user_name': None, 'read_deleted': u'no'} _safe_log /opt/stack/nova/nova/openstack/common/rpc/common.py:195
2012-11-29 19:17:34 29815 ERROR nova.openstack.common.rpc.amqp [-] Exception during message handling
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp Traceback (most recent call last):
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/openstack/common/rpc/amqp.py", line 276, in _process_data
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp rval = self.proxy.dispatch(ctxt, version, method, **args)
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/openstack/common/rpc/dispatcher.py", line 145, in dispatch
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp return getattr(proxyobj, method)(ctxt, **kwargs)
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/conductor/manager.py", line 66, in instance_get_by_uuid
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp self.db.instance_get_by_uuid(context, instance_uuid))
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/db/api.py", line 570, in instance_get_by_uuid
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp return IMPL.instance_get_by_uuid(context, uuid)
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 127, in wrapper
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp return f(*args, **kwargs)
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 1493, in instance_get_by_uuid
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp raise exception.InstanceNotFound(instance_id=uuid)
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp InstanceNotFound: Instance cec91bce-bfb5-4544-9bd6-1d43aff47b19 could not be found.
2012-11-29 19:17:34 29815 TRACE nova.openstack.common.rpc.amqp
It looks like what's happening here is that we are raising an exception, but it's not an ERROR. We need a way to tell rpc not to log exceptions that are expected and we just want to pass back to the caller to handle (and maybe log over there if they want to).