Add regression test for bug #1764883

Related-Bug: #1764883
Change-Id: If71727cde51c29231dbb9a51c5babbcdfc802bdd

nova/tests/functional/regressions/test_bug_1764883.py

@@ -0,0 +1,120 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from nova import test
+from nova.tests import fixtures as nova_fixtures
+from nova.tests.functional import integrated_helpers
+from nova.tests.unit import fake_network
+from nova.tests.unit import fake_notifier
+import nova.tests.unit.image.fake
+from nova.tests.unit import policy_fixture
+from nova.virt import fake
+
+
+class TestEvacuationWithSourceReturningDuringRebuild(
+        test.TestCase, integrated_helpers.InstanceHelperMixin):
+    """Assert the behaviour of evacuating instances when the src returns early.
+
+    This test asserts that evacuating instances end up in an ERROR state on the
+    source when that host comes back online during an evacuation while the
+    migration record is in a pre-migrating state.
+
+    This currently leads to a race between the source initialising the instance
+    and destination claim during the rebuild, both of which attempt to update
+    the underlying task_state of the instance.
+    """
+
+    def setUp(self):
+        super(TestEvacuationWithSourceReturningDuringRebuild, self).setUp()
+
+        self.useFixture(policy_fixture.RealPolicyFixture())
+
+        # The NeutronFixture is needed to stub out validate_networks in API.
+        self.useFixture(nova_fixtures.NeutronFixture(self))
+
+        # This stubs out the network allocation in compute.
+        fake_network.set_stub_network_methods(self)
+
+        # We need the computes reporting into placement for the filter
+        # scheduler to pick a host.
+        self.useFixture(nova_fixtures.PlacementFixture())
+
+        api_fixture = self.useFixture(nova_fixtures.OSAPIFixture(
+            api_version='v2.1'))
+        self.api = api_fixture.admin_api
+        # 2.11 is needed for force_down
+        # 2.14 is needed for evacuate without onSharedStorage flag
+        self.api.microversion = '2.14'
+
+        # the image fake backend needed for image discovery
+        nova.tests.unit.image.fake.stub_out_image_service(self)
+        self.addCleanup(nova.tests.unit.image.fake.FakeImageService_reset)
+
+        self.start_service('conductor')
+        self.start_service('scheduler')
+
+        # Start two computes
+        self.computes = {}
+
+        fake.set_nodes(['host1'])
+        self.addCleanup(fake.restore_nodes)
+        self.computes['host1'] = self.start_service('compute', host='host1')
+
+        fake.set_nodes(['host2'])
+        self.addCleanup(fake.restore_nodes)
+        self.computes['host2'] = self.start_service('compute', host='host2')
+
+        self.image_id = self.api.get_images()[0]['id']
+        self.flavor_id = self.api.get_flavors()[0]['id']
+
+        self.addCleanup(fake_notifier.reset)
+
+        # Stub out rebuild with a slower method allowing the src compute to be
+        # restarted once the migration hits pre-migrating after claiming
+        # resources on the dest.
+        manager_class = nova.compute.manager.ComputeManager
+        original_rebuild = manager_class._do_rebuild_instance
+
+        def start_src_rebuild(self_, context, instance, *args, **kwargs):
+            server = self.api.get_server(instance.uuid)
+            # Start the src compute once the migration is pre-migrating.
+            self._wait_for_migration_status(server, ['pre-migrating'])
+            self.computes.get(self.source_compute).start()
+            original_rebuild(self_, context, instance, *args, **kwargs)
+
+        self.stub_out('nova.compute.manager.ComputeManager.'
+                      '_do_rebuild_instance', start_src_rebuild)
+
+    def test_evacuation_with_source_compute_returning_during_rebuild(self):
+
+        # Launch an instance
+        server_request = {'name': 'server',
+                          'imageRef': self.image_id,
+                          'flavorRef': self.flavor_id}
+        server_response = self.api.post_server({'server': server_request})
+        server = self._wait_for_state_change(self.api, server_response,
+                                             'ACTIVE')
+
+        # Record where the instance is running before forcing the service down
+        self.source_compute = server['OS-EXT-SRV-ATTR:host']
+        self.computes.get(self.source_compute).stop()
+        self.api.force_down_service(self.source_compute, 'nova-compute', True)
+
+        # Start evacuating the instance from the source_host
+        self.api.post_server_action(server['id'], {'evacuate': {}})
+
+        # FIXME(lyarwood): Assert that the evacuation fails at present with the
+        # instance remaining on the source in an ERROR state.
+        self._wait_for_state_change(self.api, server, 'ERROR')
+        server = self.api.get_server(server['id'])
+        self.assertEqual(self.source_compute, server['OS-EXT-SRV-ATTR:host'])