Allow override of distributed router flag

When router_distributed=True is set in neutron.conf,
user can't override this and create a centralized router
through openstack client. Openstack client allows modifying
routers from distributed to centralized after creation but
not supporting centralized flag during creation. We allow
centralized and distributed flags during router creation
with this change.

Closes-bug: #1664255
Change-Id: I75f72ca695338ad8c381cfa89fbb9d8e61ee7bc5

doc/source/command-objects/router.rst

@@ -63,7 +63,7 @@ Create new router
     openstack router create
         [--project <project> [--project-domain <project-domain>]]
         [--enable | --disable]
-        [--distributed]
+        [--distributed | --centralized]
         [--ha | --no-ha]
         [--description <description>]
         [--availability-zone-hint <availability-zone>]
@@ -90,6 +90,19 @@ Create new router
 
     Create a distributed router
 
+    The default router type (distributed vs centralized) is determined by a
+    configuration setting in the OpenStack deployment.  Since we are unable
+    to know that default wihtout attempting to actually create a router it
+    is suggested to use either :option:`--distributed` or :option:`--centralized`
+    in situations where multiple cloud deployments may be used.
+
+.. option:: --centralized
+
+    Create a centralized router
+
+    See the note in :option:`--distributed` regarding the default used when
+    creating a new router.
+
 .. option:: --ha
 
     Create a highly available router

openstackclient/network/v2/router.py

@@ -78,8 +78,7 @@ def _get_attrs(client_manager, parsed_args):
         attrs['admin_state_up'] = True
     if parsed_args.disable:
         attrs['admin_state_up'] = False
-    # centralized is available only for SetRouter and not for CreateRouter
-    if 'centralized' in parsed_args and parsed_args.centralized:
+    if parsed_args.centralized:
         attrs['distributed'] = False
     if parsed_args.distributed:
         attrs['distributed'] = True
@@ -176,13 +175,17 @@ class CreateRouter(command.ShowOne):
             action='store_true',
             help=_("Disable router")
         )
-        parser.add_argument(
+        distribute_group = parser.add_mutually_exclusive_group()
+        distribute_group.add_argument(
             '--distributed',
-            dest='distributed',
             action='store_true',
-            default=False,
             help=_("Create a distributed router")
         )
+        distribute_group.add_argument(
+            '--centralized',
+            action='store_true',
+            help=_("Create a centralized router")
+        )
         ha_group = parser.add_mutually_exclusive_group()
         ha_group.add_argument(
             '--ha',

openstackclient/tests/unit/network/v2/test_router.py

@@ -211,6 +211,35 @@ class TestCreateRouter(TestRouter):
     def test_create_with_no_ha_option(self):
         self._test_create_with_ha_options('--no-ha', False)
 
+    def _test_create_with_distributed_options(self, option, distributed):
+        arglist = [
+            option,
+            self.new_router.name,
+        ]
+        verifylist = [
+            ('name', self.new_router.name),
+            ('enable', True),
+            ('distributed', distributed),
+            ('centralized', not distributed),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        columns, data = (self.cmd.take_action(parsed_args))
+
+        self.network.create_router.assert_called_once_with(**{
+            'admin_state_up': True,
+            'name': self.new_router.name,
+            'distributed': distributed,
+        })
+        self.assertEqual(self.columns, columns)
+        self.assertEqual(self.data, data)
+
+    def test_create_with_distributed_option(self):
+        self._test_create_with_distributed_options('--distributed', True)
+
+    def test_create_with_centralized_option(self):
+        self._test_create_with_distributed_options('--centralized', False)
+
     def test_create_with_AZ_hints(self):
         arglist = [
             self.new_router.name,

releasenotes/notes/bug-1664255-f82c5c13d92fed2a.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Allow users to create centralized (distributed=False)
+    routers using the ``--centralized`` option in ``router create``.
+    Without this, routers are created based on the default
+    neutron configuration of the deployment, which, for example,
+    could be 'distributed'.
+    [Bug `1664255 <https://bugs.launchpad.net/bugs/1664255>`_]