config options: Improve help for conductor

This patch improves help text for conductor related configuration options.

Implements blueprint centralize-config-options-newton

Change-Id: Ieb4268fa03b0037d16bcc0b83e9fb0c72849685d

nova/conf/conductor.py

@@ -1,8 +1,4 @@
-# needs:fix_opt_description
 # needs:check_deprecation_status
-# needs:check_opt_group_and_type
-# needs:fix_opt_description_indentation
-# needs:fix_opt_registration_consistency
 
 
 # Copyright (c) 2010 OpenStack Foundation
@@ -24,55 +20,73 @@ from oslo_config import cfg
 
 conductor_group = cfg.OptGroup(
     'conductor',
-    title='Conductor Options')
-
-use_local = cfg.BoolOpt(
-    'use_local',
-    default=False,
-    help='DEPRECATED: Perform nova-conductor operations locally. '
-         'This legacy mode was introduced to bridge a gap during '
-         'the transition to the conductor service. It no longer '
-         'represents a reasonable alternative for deployers. '
-         'Removal may be as early as 14.0',
-    deprecated_for_removal=True)
-
-topic = cfg.StrOpt(
-    'topic',
-    default='conductor',
-    help='The topic on which conductor nodes listen')
-
-manager = cfg.StrOpt(
-    'manager',
-    default='nova.conductor.manager.ConductorManager',
-    help=('DEPRECATED: Full class name for the Manager for conductor. '
-          'Removal in 14.0'),
-    deprecated_for_removal=True)
-
-workers = cfg.IntOpt(
-    'workers',
-    help='Number of workers for OpenStack Conductor service. '
-         'The default will be the number of CPUs available.')
-
-migrate_opt = cfg.IntOpt(
-    'migrate_max_retries',
-    default=-1,
-    help='Number of times to retry live-migration before failing. '
-         'If == -1, try until out of hosts. '
-         'If == 0, only try once, no retries.')
+    title='Conductor Options',
+    help="""
+Options under this group are used to define Conductor's communication,
+which manager should be act as a proxy between computes and database,
+and finally, how many worker processes will be used.
+""",
+)
 
 ALL_OPTS = [
-    use_local,
-    topic,
-    manager,
-    workers]
+    cfg.BoolOpt(
+        'use_local',
+        default=False,
+        deprecated_for_removal=True,
+        help="""
+Perform nova-conductor operations locally. This legacy mode was
+introduced to bridge a gap during the transition to the conductor service.
+It no longer represents a reasonable alternative for deployers.
+
+Removal may be as early as 14.0.
+"""),
+    # TODO(macsz) deprecate this option
+    cfg.StrOpt(
+        'topic',
+        default='conductor',
+        help="""
+Topic exchange name on which conductor nodes listen.
+"""),
+    cfg.StrOpt(
+        'manager',
+        default='nova.conductor.manager.ConductorManager',
+        deprecated_for_removal=True,
+        help="""
+Full class name for the Manager for conductor.
+
+Removal in 14.0
+"""),
+    cfg.IntOpt(
+        'workers',
+        help="""
+Number of workers for OpenStack Conductor service. The default will be the
+number of CPUs available.
+"""),
+]
+
+migrate_opts = [
+    cfg.IntOpt(
+        'migrate_max_retries',
+        default=-1,
+        min=-1,
+        help="""
+Number of times to retry live-migration before failing.
+
+Possible values:
+
+* If == -1, try until out of hosts (default)
+* If == 0, only try once, no retries
+* Integer greater than 0
+"""),
+]
 
 
 def register_opts(conf):
     conf.register_group(conductor_group)
     conf.register_opts(ALL_OPTS, group=conductor_group)
-    conf.register_opts([migrate_opt])
+    conf.register_opts(migrate_opts)
 
 
 def list_opts():
-    return {"DEFAULT": [migrate_opt],
+    return {"DEFAULT": migrate_opts,
             conductor_group: ALL_OPTS}