deprecate manager class options

We should deprecate the manager classes used for all of our
services. This is not a thing we actually expect or want to support
people replacing. If we want modular plug points at any of these all
the options should be in tree and specified by constants to switch
between.

Change-Id: Id25bd4870c6e2fda08dc0177b7ed61a8a6091838

nova/conf/cells.py

@@ -75,7 +75,7 @@
     cfg.StrOpt('manager',
                default='nova.cells.manager.CellsManager',
                help="""
-Manager for cells
+DEPRECATED: Manager for cells
 
 The nova-cells manager class. This class defines RPC methods that
 the local cell may call. This class is NOT used for messages coming
@@ -102,7 +102,9 @@
 Related options:
 
 * None
-"""),
+""",
+        deprecated_for_removal=True
+    ),
     cfg.StrOpt('name',
                 default='nova',
                 help="""

nova/service.py

@@ -76,7 +76,8 @@
                     'will be the number of CPUs available.'),
     cfg.StrOpt('metadata_manager',
                default='nova.api.manager.MetadataManager',
-               help='OpenStack metadata service manager'),
+               help='DEPRECATED: OpenStack metadata service manager',
+               deprecated_for_removal=True),
     cfg.StrOpt('metadata_listen',
                default="0.0.0.0",
                help='The IP address on which the metadata API will listen.'),
@@ -88,24 +89,36 @@
     cfg.IntOpt('metadata_workers',
                help='Number of workers for metadata service. The default will '
                     'be the number of CPUs available.'),
+    # NOTE(sdague): Ironic is still using this facility for their HA
+    # manager. Ensure they are sorted before removing this.
     cfg.StrOpt('compute_manager',
                default='nova.compute.manager.ComputeManager',
-               help='Full class name for the Manager for compute'),
+               help='DEPRECATED: Full class name for the Manager for compute',
+               deprecated_for_removal=True),
     cfg.StrOpt('console_manager',
                default='nova.console.manager.ConsoleProxyManager',
-               help='Full class name for the Manager for console proxy'),
+               help='DEPRECATED: Full class name for the Manager for '
+                   'console proxy',
+               deprecated_for_removal=True),
     cfg.StrOpt('consoleauth_manager',
                default='nova.consoleauth.manager.ConsoleAuthManager',
-               help='Manager for console auth'),
+               help='DEPRECATED: Manager for console auth',
+               deprecated_for_removal=True),
     cfg.StrOpt('cert_manager',
                default='nova.cert.manager.CertManager',
-               help='Full class name for the Manager for cert'),
+               help='DEPRECATED: Full class name for the Manager for cert',
+               deprecated_for_removal=True),
+    # NOTE(sdague): the network_manager has a bunch of different in
+    # tree classes that are still legit options. In Newton we should
+    # turn this into a selector.
     cfg.StrOpt('network_manager',
                default='nova.network.manager.VlanManager',
                help='Full class name for the Manager for network'),
     cfg.StrOpt('scheduler_manager',
                default='nova.scheduler.manager.SchedulerManager',
-               help='Full class name for the Manager for scheduler'),
+               help='DEPRECATED: Full class name for the Manager for '
+                   'scheduler',
+               deprecated_for_removal=True),
     cfg.IntOpt('service_down_time',
                default=60,
                help='Maximum time since last check-in for up service'),

releasenotes/notes/deprecate_pluggable_managers-ca0224bcd779454c.yaml

@@ -0,0 +1,19 @@
+---
+deprecations:
+
+  - Nove used to support the concept that ``service managers`` were
+    replaceable components. There are many config options where you can
+    replace a manager by specifying a new class. This concept is
+    deprecated in Mitaka as are the following config options.
+
+      * [cells] manager
+      * metadata_manager
+      * compute_manager
+      * console_manager
+      * consoleauth_manager
+      * cert_manager
+      * scheduler_manager
+
+    Many of these will be removed in Newton. Users of these options
+    are encouraged to work with Nova upstream on any features missing
+    in the default implementations that are needed.