Deprecate nova-manage vm list command

The nova-manage vm command is replaced with the nova list command
in python-novaclient, and has been for a long time.

As of microversion 2.3, the fields that are output from
nova-manage vm list are all covered in the REST API for showing server
details, which can also be used via the --fields option of the nova
list command. The nova list command also allows filtering by host.

This sets the timer for deprecation and then removal in Ocata.

Change-Id: Ibce8c3deb24a16019b721d3b91640ca342ae541b
Closes-Bug: #1494841

doc/source/man/nova-manage.rst

@@ -162,6 +162,9 @@ Nova Images
 Nova VM
 ~~~~~~~~~~~
 
+**DEPRECATED** Use the nova list command from python-novaclient instead.
+The vm subcommand will be removed in the 15.0.0 Ocata release.
+
 ``nova-manage vm list [host]``
     Show a list of all instances. Accepts optional hostname (to show only instances on specific host).
 

nova/cmd/manage.py

@@ -662,9 +662,13 @@ class NetworkCommands(object):
 class VmCommands(object):
     """Class for managing VM instances."""
 
+    description = ('DEPRECATED: Use the nova list command from '
+                   'python-novaclient instead. The vm subcommand will be '
+                   'removed in the 15.0.0 Ocata release.')
+
     @args('--host', metavar='<host>', help='Host')
     def list(self, host=None):
-        """Show a list of all instances."""
+        """DEPRECATED: Show a list of all instances."""
 
         print(("%-10s %-15s %-10s %-10s %-26s %-9s %-9s %-9s"
                "  %-10s %-10s %-10s %-5s" % (_('instance'),

releasenotes/notes/deprecate-nova-manage-vm-list-571162f55173cccc.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - The ``nova-manage vm list`` command is deprecated and will be removed in
+    the 15.0.0 Ocata release. Use the ``nova list`` command from
+    python-novaclient instead.