Remove cells topic configuration option

This has been deprecated since 15.0.0. It will now continue to use the
default value 'cells'.

Change-Id: Ic2922f0a64f8a099778d3f6934143080d4ea1ccd

nova/cells/__init__.py

@@ -15,3 +15,5 @@
 """
 Cells
 """
+
+TOPIC = 'cells'

nova/cells/rpcapi.py

@@ -27,6 +27,7 @@ from oslo_log import log as logging
 import oslo_messaging as messaging
 from oslo_serialization import jsonutils
 
+from nova import cells
 import nova.conf
 from nova import exception
 from nova import objects
@@ -135,7 +136,7 @@ class CellsAPI(object):
 
     def __init__(self):
         super(CellsAPI, self).__init__()
-        target = messaging.Target(topic=CONF.cells.topic, version='1.0')
+        target = messaging.Target(topic=cells.TOPIC, version='1.0')
         version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.cells,
                                                CONF.upgrade_levels.cells)
         # NOTE(sbauza): Yes, this is ugly but cells_utils is calling cells.db

nova/cmd/cells.py

@@ -20,6 +20,7 @@ import sys
 from oslo_log import log as logging
 from oslo_reports import guru_meditation_report as gmr
 
+from nova import cells
 import nova.conf
 from nova import config
 from nova import objects
@@ -39,7 +40,7 @@ def main():
     gmr.TextGuruMeditation.setup_autorun(version)
 
     server = service.Service.create(binary='nova-cells',
-                                    topic=CONF.cells.topic,
+                                    topic=cells.TOPIC,
                                     manager='nova.cells.manager.CellsManager')
     service.serve(server)
     service.wait()

nova/conf/cells.py

@@ -29,25 +29,6 @@ required and all Nova deployments will be at least a cells v2 cell of one.
 """)
 
 cells_opts = [
-    cfg.StrOpt('topic',
-        default='cells',
-        deprecated_for_removal=True,
-        deprecated_since='15.0.0',
-        deprecated_reason="""
-Configurable RPC topics provide little value and can result in a wide variety
-of errors. They should not be used.
-""",
-        help="""
-Topic.
-
-This is the message queue topic that cells nodes listen on. It is
-used when the cells service is started up to configure the queue,
-and whenever an RPC call to the scheduler is made.
-
-Possible values:
-
-* cells: This is the recommended and the default value.
-"""),
     cfg.BoolOpt('enable',
         default=False,
         help="""

nova/tests/unit/cells/test_cells_rpcapi.py

@@ -34,9 +34,9 @@ class CellsAPITestCase(test.NoDBTestCase):
 
     def setUp(self):
         super(CellsAPITestCase, self).setUp()
-        self.fake_topic = 'fake_topic'
+        self.fake_topic = 'cells'
         self.fake_context = 'fake_context'
-        self.flags(topic=self.fake_topic, enable=True, group='cells')
+        self.flags(enable=True, group='cells')
         self.cells_rpcapi = cells_rpcapi.CellsAPI()
 
     def _stub_rpc_method(self, rpc_method, result):

releasenotes/notes/remove-nova-cells-topic-config-a7cd4d1a3e2d7d5b.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    The cells topic configuration option has been removed. Please make sure
+    your cells related message queue topic is 'cells'.