Add --migrate option to subcloud unmanage

This commit adds the --migrate option to the subcloud unmanage command,
besides unmanaging the subcloud it also changes its deploy status to
'rehome-pending'. It should be used when unmanaging a subcloud before
the rehoming/migration operation. This new status will then be used by
cert-mon to determine when it should stop auditing an unmanaged
subcloud, to avoid certificate issues during the rehoming operation.

It's only possible to use this option when the subcloud's deploy status
is 'complete'. It's possible to manage it back in case the rehoming
operation is not going to be executed anymore; in this case the
deploy-status will be reverted back to 'complete'.

Example usage:
dcmanager subcloud unmanage --migrate subcloud1

Test Plan:
1. PASS - Unmanage a subcloud without --migrate and verify that it
          still works and that cert-mon continues to audit it;
2. PASS - Manage a subcloud, verify that the operation still works as
          expected;
3. PASS - Try to unmanage with --migrate when the subcloud's deploy
          status is different than 'complete' and verify that it
          doesn't allow it;
4. PASS - Unmanage a subcloud using the --migrate option and verify
          that its deploy status changes to 'rehome-pending', all the
          sync statuses change to 'unknown', and that cert-mon stops
          auditing the subcloud;
5. PASS - Manage a 'rehome-pending' subcloud and verify that it
          succeeds while also reverting its deploy_status to
          'complete';

Depends-on: https://review.opendev.org/c/starlingx/distcloud/+/900288

Story: 2010852
Task: 49060

Signed-off-by: Gustavo Herzmann <gustavo.herzmann@windriver.com>
Change-Id: I1d761c1a0ae401a11443d80df70338acb2a0a14a

distributedcloud-client/dcmanagerclient/commands/v1/subcloud_manager.py

@@ -422,6 +422,14 @@ class UnmanageSubcloud(base.DCManagerShowOne):
             'subcloud',
             help='Name or ID of the subcloud to unmanage.'
         )
+
+        parser.add_argument(
+            '--migrate',
+            required=False,
+            action='store_true',
+            help='Mark the subcloud for an upcoming migration.'
+        )
+
         return parser
 
     def _get_resources(self, parsed_args):
@@ -429,6 +437,10 @@ class UnmanageSubcloud(base.DCManagerShowOne):
         dcmanager_client = self.app.client_manager.subcloud_manager
         kwargs = dict()
         kwargs['management-state'] = 'unmanaged'
+
+        if parsed_args.migrate:
+            kwargs['migrate'] = 'true'
+
         try:
             result = dcmanager_client.subcloud_manager.update_subcloud(
                 subcloud_ref, files=None, data=kwargs)

distributedcloud-client/dcmanagerclient/tests/v1/test_subcloud_manager.py

@@ -221,6 +221,15 @@ class TestCLISubcloudManagerV1(base.BaseCommandTest):
             base.SUBCLOUD_FIELD_RESULT_LIST_WITH_PEERID,
             actual_call[1])
 
+    def test_unmanage_subcloud_with_migrate(self):
+        self.client.subcloud_manager.update_subcloud.\
+            return_value = [base.SUBCLOUD_RESOURCE]
+        actual_call = self.call(
+            subcloud_cmd.UnmanageSubcloud, app_args=[base.ID, '--migrate'])
+        self.assertEqual(
+            base.SUBCLOUD_FIELD_RESULT_LIST_WITH_PEERID,
+            actual_call[1])
+
     def test_unmanage_subcloud_without_subcloud_id(self):
         self.assertRaises(SystemExit, self.call,
                           subcloud_cmd.UnmanageSubcloud, app_args=[])