Merge "Add a warning in 'nova-manage cell_v2 delete_cell'"

doc/source/cli/nova-manage.rst

@@ -213,7 +213,9 @@ Nova Cells v2
     the cell and the hosts are deleted successfully with ``--force`` option,
     1 if a cell with that uuid could not be found, 2 if host mappings were
     found for the cell (cell not empty) without ``--force`` option, and 3
-    if there are instances mapped to the cell (cell not empty).
+    if there are instances mapped to the cell (cell not empty), 4 if there are
+    instance mappings to the cell but all instances have been deleted
+    in the cell.
 
 ``nova-manage cell_v2 list_hosts [--cell_uuid <cell_uuid>]``
 

nova/cmd/manage.py

@@ -1393,9 +1393,21 @@ class CellV2Commands(object):
         instance_mappings = objects.InstanceMappingList.get_by_cell_id(
             ctxt, cell_mapping.id)
         if instance_mappings:
+            with context.target_cell(ctxt, cell_mapping) as cctxt:
+                instances = objects.InstanceList.get_all(cctxt)
+            if instances:
+                # There are instances in the cell.
                 print(_('There are existing instances mapped to cell with '
                         'uuid %s.') % cell_uuid)
                 return 3
+            # There are no instances in the cell but the records remains
+            # in the 'instance_mappings' table.
+            print(_("There are instance mappings to cell with uuid %s, "
+                    "but all instances have been deleted "
+                    "in the cell.") % cell_uuid)
+            print(_("So execute 'nova-manage db archive_deleted_rows' to "
+                    "delete the instance mappings."))
+            return 4
 
         # Delete hosts mapped to the cell.
         for host_mapping in host_mappings:

nova/tests/unit/test_nova_manage.py

@@ -1691,10 +1691,14 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         output = self.output.getvalue().strip()
         self.assertIn('There are existing hosts mapped to cell', output)
 
-    def test_delete_cell_instance_mappings_exist(self):
+    @mock.patch.object(objects.InstanceList, 'get_all')
+    def test_delete_cell_instance_mappings_exist_with_instances(
+        self, mock_get_all):
         """Tests trying to delete a cell which has instance mappings."""
         cell_uuid = uuidutils.generate_uuid()
         ctxt = context.get_admin_context()
+        mock_get_all.return_value = [objects.Instance(
+            ctxt, uuid=uuidsentinel.instance)]
         # create the cell mapping
         cm = objects.CellMapping(
             context=ctxt, uuid=cell_uuid, database_connection='fake:///db',
@@ -1709,6 +1713,31 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         output = self.output.getvalue().strip()
         self.assertIn('There are existing instances mapped to cell', output)
 
+    @mock.patch.object(objects.InstanceList, 'get_all',
+                       return_value=[])
+    def test_delete_cell_instance_mappings_exist_without_instances(
+        self, mock_get_all):
+        """Tests trying to delete a cell which has instance mappings."""
+        cell_uuid = uuidutils.generate_uuid()
+        ctxt = context.get_admin_context()
+        # create the cell mapping
+        cm = objects.CellMapping(
+            context=ctxt, uuid=cell_uuid, database_connection='fake:///db',
+            transport_url='fake:///mq')
+        cm.create()
+        # create an instance mapping in this cell
+        im = objects.InstanceMapping(
+            context=ctxt, instance_uuid=uuidutils.generate_uuid(),
+            cell_mapping=cm, project_id=uuidutils.generate_uuid())
+        im.create()
+        self.assertEqual(4, self.commands.delete_cell(cell_uuid))
+        output = self.output.getvalue().strip()
+        self.assertIn('There are instance mappings to cell with uuid', output)
+        self.assertIn('but all instances have been deleted in the cell.',
+                      output)
+        self.assertIn("So execute 'nova-manage db archive_deleted_rows' to "
+                      "delete the instance mappings.", output)
+
     def test_delete_cell_success_without_host_mappings(self):
         """Tests trying to delete an empty cell."""
         cell_uuid = uuidutils.generate_uuid()

releasenotes/notes/bug-1725331-fcf93514045a557a.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    The ``nova-manage cell_v2 delete_cell`` command returns an exit code 4
+    when there are instance mappings to a cell to delete but all instances
+    have been deleted in the cell.