Merge "Functional reproduction for bug 1845291"

nova/tests/functional/regressions/test_bug_1845291.py

@@ -0,0 +1,87 @@
+# 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.
+import mock
+
+import nova
+from nova import exception
+from nova.tests.functional import integrated_helpers
+
+
+class ForcedHostMissingReScheduleTestCase(
+    integrated_helpers.ProviderUsageBaseTestCase):
+
+    compute_driver = 'fake.SmallFakeDriver'
+
+    def setUp(self):
+        super(ForcedHostMissingReScheduleTestCase, self).setUp()
+        self._start_compute(host="host1")
+        self._start_compute(host="host2")
+        self._start_compute(host="host3")
+
+        flavors = self.api.get_flavors()
+        self.flavor1 = flavors[0]
+
+    def test_boot_with_az_and_host_then_migrate_re_schedules(self):
+        """Ensure that re-schedule is possible on migration even if the server
+        is originally booted with forced host.
+
+        The _boot_and_check_allocations() will start a server forced to host1.
+        Then a migration is triggered. Both host2 and host3 are valid targets.
+        But the test mocks resize_claim to make the first dest host fail and
+        expects that nova will try the alternative host.
+        """
+
+        server = self._boot_and_check_allocations(
+            self.flavor1, 'host1')
+
+        orig_claim = nova.compute.resource_tracker.ResourceTracker.resize_claim
+        claim_calls = []
+
+        def fake_orig_claim(
+                _self, context, instance, instance_type, nodename,
+                *args, **kwargs):
+            if not claim_calls:
+                claim_calls.append(nodename)
+                raise exception.ComputeResourcesUnavailable(
+                    reason='Simulated claim failure')
+            else:
+                claim_calls.append(nodename)
+                return orig_claim(
+                    _self, context, instance, instance_type, nodename, *args,
+                    **kwargs)
+
+        with mock.patch(
+                'nova.compute.resource_tracker.ResourceTracker.resize_claim',
+                new=fake_orig_claim):
+            # Now migrate the server which is going to fail on the first
+            # destination but then will expect to be rescheduled.
+            self.api.post_server_action(server['id'], {'migrate': None})
+
+            # We expect that the instance re-scheduled but successfully ended
+            # up on the second destination host.
+            # FIXME(gibi): this is bug 1845291 as nova does not try to
+            # re-schedule. The forced host was not cleared from the
+            # RequestSpec before the MigrationTask populated the retry
+            # information for the re-scheduling.
+            # self._wait_for_server_parameter(
+            #     self.api, server,
+            #     {
+            #         'OS-EXT-STS:task_state': None,
+            #         'status': 'VERIFY_RESIZE'})
+            # Instead the server goes to ERROR state
+            self._wait_for_server_parameter(
+                self.api, server, {'status': 'ERROR'})
+
+        # we ensure that there was a failed and then a successful claim call
+        # FIXME(gibi): this is bug 1845291 as there was no second claim call
+        # self.assertEqual(2, len(claim_calls))
+        self.assertEqual(1, len(claim_calls))