Add the beginnings of the nova-conductor service

This adds a new service called "nova-conductor" which will provide
services for nova-compute, such as completing database updates and
handling long-running tasks.

Right now, this just adds a fraction of the database-related work
so that we can proceed with incremental changes to nova-compute.

For compatibility/flexibility, both LocalAPI and (RPC)API classes
are provided. Users concerned with performance or compatibility
who wish to maintain compute-node-local database accesses can
set the [conductor] use_local=True, which will mimic the legacy
behavior.

DocImpact

Change-Id: Ib81d879f40b7daceeffad5af0631c7db68168661

bin/nova-conductor

@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    Copyright 2012 IBM Corp.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Starter script for Nova Conductor."""
+
+import eventlet
+eventlet.monkey_patch()
+
+import os
+import sys
+
+# If ../nova/__init__.py exists, add ../ to Python search path, so that
+# it will override what happens to be installed in /usr/(local/)lib/python...
+possible_topdir = os.path.normpath(os.path.join(os.path.abspath(sys.argv[0]),
+                                   os.pardir,
+                                   os.pardir))
+if os.path.exists(os.path.join(possible_topdir, 'nova', '__init__.py')):
+    sys.path.insert(0, possible_topdir)
+
+
+from nova import config
+from nova.openstack.common import log as logging
+from nova import service
+from nova import utils
+
+CONF = config.CONF
+CONF.import_opt('topic', 'nova.conductor.api', group='conductor')
+
+if __name__ == '__main__':
+    config.parse_args(sys.argv)
+    logging.setup("nova")
+    utils.monkey_patch()
+    server = service.Service.create(binary='nova-conductor',
+                                    topic=CONF.conductor.topic,
+                                    manager=CONF.conductor.manager)
+    service.serve(server)
+    service.wait()