Add functional recreate test for bug 1852610

It is possible to delete a source compute service which has
pending migration-based allocations and servers in VERIFY_RESIZE
status. Doing so deletes the compute service and compute node
but orphans the source node resource provider along with its
resource allocations held by the migration record while there
is a pending resized server.

This adds a simple cold migrate test which deletes the source
compute service while the server is in VERIFY_RESIZE status and
then tries to confirm the resize which fails.

Change-Id: I644608b4e197ddea31c5f264adb492f2c8931f04
Related-Bug: #1852610

Author: mriedem

nova/tests/functional/wsgi/test_services.py

@@ -175,6 +175,41 @@ def test_evacuate_then_delete_compute_service(self):
         self.assertIn('Error updating resources for node host1.', log_output)
         self.assertIn('Failed to create resource provider host1', log_output)
 
+    def test_migrate_confirm_after_deleted_source_compute(self):
+        """Tests a scenario where a server is cold migrated and while in
+        VERIFY_RESIZE status the admin attempts to delete the source compute
+        and then the user tries to confirm the resize.
+        """
+        # Start a compute service and create a server there.
+        self._start_compute('host1')
+        host1_rp_uuid = self._get_provider_uuid_by_host('host1')
+        flavor = self.api.get_flavors()[0]
+        server = self._boot_and_check_allocations(flavor, 'host1')
+        # Start a second compute service so we can cold migrate there.
+        self._start_compute('host2')
+        host2_rp_uuid = self._get_provider_uuid_by_host('host2')
+        # Cold migrate the server to host2.
+        self._migrate_and_check_allocations(
+            server, flavor, host1_rp_uuid, host2_rp_uuid)
+        # Delete the source compute service.
+        service = self.admin_api.get_services(
+            binary='nova-compute', host='host1')[0]
+        self.admin_api.api_delete('/os-services/%s' % service['id'])
+        # FIXME(mriedem): This is bug 1852610 where the compute service is
+        # deleted but the resource provider is not because there are still
+        # migration-based allocations against the source node provider.
+        resp = self.placement_api.get('/resource_providers/%s' % host1_rp_uuid)
+        self.assertEqual(200, resp.status)
+        self.assertFlavorMatchesUsage(host1_rp_uuid, flavor)
+        # Now try to confirm the migration.
+        # FIXME(mriedem): This will fail until bug 1852610 is fixed and the
+        # source compute service delete is blocked while there is an
+        # in-progress migration involving the node.
+        self.assertNotIn('ComputeHostNotFound', self.stdlog.logger.output)
+        self.api.post_server_action(server['id'], {'confirmResize': None})
+        self._wait_for_state_change(self.api, server, 'ERROR')
+        self.assertIn('ComputeHostNotFound', self.stdlog.logger.output)
+
 
 class ComputeStatusFilterTest(integrated_helpers.ProviderUsageBaseTestCase):
     """Tests the API, compute service and Placement interaction with the