Reset the mapped field of nodes at service deletion

Make sure that the 'mapped' field of compute nodes is reset
to 0 at nova-compute service deletion.

To let nova-manage create the missing host mapping in nova_api
database.

Closes-Bug: #2085135
Change-Id: I774d4312d7e94af94d960f7269717a00fa08c583
Signed-off-by: Julien Le Jeune <julien.le-jeune@ovhcloud.com>

nova/db/main/api.py

@@ -383,11 +383,18 @@ def service_destroy(context, service_id):
     if service.binary == 'nova-compute':
         # TODO(sbauza): Remove the service_id filter in a later release
         # once we are sure that all compute nodes report the host field
+        # NOTE(jlejeune): Make sure that the mapped field of the
+        # relevant compute nodes is set to 0
+        # See https://bugs.launchpad.net/nova/+bug/2085135.
         model_query(context, models.ComputeNode).\
             filter(sql.or_(
                 models.ComputeNode.service_id == service_id,
                 models.ComputeNode.host == service['host'])).\
-            soft_delete(synchronize_session=False)
+            update({'deleted': models.ComputeNode.id,
+                    'updated_at': models.ComputeNode.updated_at,
+                    'deleted_at': timeutils.utcnow(),
+                    'mapped': 0},
+                   synchronize_session=False)
 
 
 @pick_context_manager_reader

nova/tests/functional/regressions/test_bug_2085135.py

@@ -69,7 +69,7 @@ class HostMappingDiscoveryTestFail(test.TestCase):
         self.assertEqual(node['uuid'], node_uuid)
 
         # Bug #2085135: node should be unmapped and be discoverable
-        self.assertEqual(node['mapped'], 1)
+        self.assertEqual(node['mapped'], 0)
         mappings = host_mapping.discover_hosts(
             self.ctxt, status_fn=lambda m: None)
-        self.assertEqual(0, len(mappings))
+        self.assertEqual(1, len(mappings))

nova/tests/unit/db/main/test_api.py

@@ -2941,6 +2941,20 @@ class ServiceTestCase(test.TestCase, ModelsObjectComparatorMixin):
         # make sure ComputeHostNotFound is not raised
         db.compute_node_get(self.ctxt, compute_node['id'])
 
+    def test_service_destroy_and_reset_mapped_field(self):
+        # Test added for bug #2085135, this test tests that mapped
+        # field of deleted compute node is reset to 0
+        service = self._create_service({'binary': 'nova-compute',
+                                        'host': 'host1'})
+        compute_node_dict = _make_compute_node('host1', 'node1', 'kvm', None)
+        compute_node = db.compute_node_create(self.ctxt, compute_node_dict)
+        db.service_destroy(self.ctxt, service['id'])
+
+        # check that compute_node's mapped filed is reset to 0
+        self.ctxt.read_deleted = "yes"
+        cn = db.compute_node_get(self.ctxt, compute_node['id'])
+        self.assertEqual(cn['mapped'], 0)
+
     def test_service_update(self):
         service = self._create_service({})
         new_values = {