Merge pull request #2 from stackhpc/bug-1839560

priteau · web-flow · commit 22eb001c066e · 2019-09-27T12:41:28.000+02:00
Fix for bugs 1839560 and 1839674
diff --git a/nova/compute/resource_tracker.py b/nova/compute/resource_tracker.py
@@ -580,8 +580,12 @@ def _init_compute_node(self, context, resources):
         cn = objects.ComputeNode(context)
         cn.host = self.host
         self._copy_resources(cn, resources)
-        self.compute_nodes[nodename] = cn
         cn.create()
+        # Only map the ComputeNode into compute_nodes if create() was OK
+        # because if create() fails, on the next run through here nodename
+        # would be in compute_nodes and we won't try to create again (because
+        # of the logic above).
+        self.compute_nodes[nodename] = cn
         LOG.info('Compute node record created for '
                  '%(host)s:%(node)s with uuid: %(uuid)s',
                  {'host': self.host, 'node': nodename, 'uuid': cn.uuid})
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
@@ -30,6 +30,7 @@
 from oslo_db.sqlalchemy import update_match
 from oslo_db.sqlalchemy import utils as sqlalchemyutils
 from oslo_log import log as logging
+from oslo_utils import excutils
 from oslo_utils import importutils
 from oslo_utils import timeutils
 from oslo_utils import uuidutils
@@ -693,11 +694,54 @@ def compute_node_create(context, values):
 
     compute_node_ref = models.ComputeNode()
     compute_node_ref.update(values)
-    compute_node_ref.save(context.session)
+    try:
+        compute_node_ref.save(context.session)
+    except db_exc.DBDuplicateEntry:
+        with excutils.save_and_reraise_exception(logger=LOG) as err_ctx:
+            # Check to see if we have a (soft) deleted ComputeNode with the
+            # same UUID and if so just update it and mark as no longer (soft)
+            # deleted. See bug 1839560 for details.
+            if 'uuid' in values:
+                # Get a fresh context for a new DB session and allow it to
+                # get a deleted record.
+                ctxt = nova.context.get_admin_context(read_deleted='yes')
+                compute_node_ref = _compute_node_get_and_update_deleted(
+                    ctxt, values)
+                # If we didn't get anything back we failed to find the node
+                # by uuid and update it so re-raise the DBDuplicateEntry.
+                if compute_node_ref:
+                    err_ctx.reraise = False
 
     return compute_node_ref
 
 
+@pick_context_manager_writer
+def _compute_node_get_and_update_deleted(context, values):
+    """Find a ComputeNode by uuid, update and un-delete it.
+
+    This is a special case from the ``compute_node_create`` method which
+    needs to be separate to get a new Session.
+
+    This method will update the ComputeNode, if found, to have deleted=0 and
+    deleted_at=None values.
+
+    :param context: request auth context which should be able to read deleted
+        records
+    :param values: values used to update the ComputeNode record - must include
+        uuid
+    :return: updated ComputeNode sqlalchemy model object if successfully found
+        and updated, None otherwise
+    """
+    cn = model_query(
+        context, models.ComputeNode).filter_by(uuid=values['uuid']).first()
+    if cn:
+        # Update with the provided values but un-soft-delete.
+        update_values = copy.deepcopy(values)
+        update_values['deleted'] = 0
+        update_values['deleted_at'] = None
+        return compute_node_update(context, cn.id, update_values)
+
+
 @oslo_db_api.wrap_db_retry(max_retries=5, retry_on_deadlock=True)
 @pick_context_manager_writer
 def compute_node_update(context, compute_id, values):
diff --git a/nova/tests/functional/regressions/test_bug_1839560.py b/nova/tests/functional/regressions/test_bug_1839560.py
@@ -0,0 +1,113 @@
+# 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 oslo_log import log as logging
+
+from nova import context
+from nova.db import api as db_api
+from nova import objects
+from nova import test
+from nova.tests import fixtures as nova_fixtures
+from nova.tests.functional import integrated_helpers
+from nova import utils
+from nova.virt import fake as fake_virt
+
+LOG = logging.getLogger(__name__)
+
+
+class PeriodicNodeRecreateTestCase(test.TestCase,
+                                   integrated_helpers.InstanceHelperMixin):
+    """Regression test for bug 1839560 introduced in Rocky.
+
+    When an ironic node is undergoing maintenance the driver will not report
+    it as an available node to the ComputeManager.update_available_resource
+    periodic task. The ComputeManager will then (soft) delete a ComputeNode
+    record for that no-longer-available node. If/when the ironic node is
+    available again and the driver reports it, the ResourceTracker will attempt
+    to create a ComputeNode record for the ironic node.
+
+    The regression with change Ia69fabce8e7fd7de101e291fe133c6f5f5f7056a is
+    that the ironic node uuid is used as the ComputeNode.uuid and there is
+    a unique constraint on the ComputeNode.uuid value in the database. So
+    trying to create a ComputeNode with the same uuid (after the ironic node
+    comes back from being unavailable) fails with a DuplicateEntry error since
+    there is a (soft) deleted version of the ComputeNode with the same uuid
+    in the database.
+    """
+    def setUp(self):
+        super(PeriodicNodeRecreateTestCase, self).setUp()
+        # We need the PlacementFixture for the compute nodes to report in but
+        # otherwise don't care about placement for this test.
+        self.useFixture(nova_fixtures.PlacementFixture())
+        # Start up the API so we can query the os-hypervisors API.
+        self.api = self.useFixture(nova_fixtures.OSAPIFixture(
+            api_version='v2.1')).admin_api
+        # Make sure we're using the fake driver that has predictable uuids
+        # for each node.
+        self.flags(compute_driver='fake.PredictableNodeUUIDDriver')
+
+    def test_update_available_resource_node_recreate(self):
+        # First we create a compute service to manage a couple of fake nodes.
+        # When start_service runs, it will create the node1 and node2
+        # ComputeNodes.
+        fake_virt.set_nodes(['node1', 'node2'])
+        self.addCleanup(fake_virt.restore_nodes)
+        compute = self.start_service('compute', 'node1')
+        # Now we should have two compute nodes, make sure the hypervisors API
+        # shows them.
+        hypervisors = self.api.api_get('/os-hypervisors').body['hypervisors']
+        self.assertEqual(2, len(hypervisors), hypervisors)
+        self.assertEqual({'node1', 'node2'},
+                         set([hyp['hypervisor_hostname']
+                              for hyp in hypervisors]))
+        # Now stub the driver to only report node1. This is making it look like
+        # node2 is no longer available when update_available_resource runs.
+        compute.manager.driver._nodes = ['node1']
+        ctxt = context.get_admin_context()
+        compute.manager.update_available_resource(ctxt)
+        # node2 should have been deleted, check the logs and API.
+        log = self.stdlog.logger.output
+        self.assertIn('Deleting orphan compute node', log)
+        self.assertIn('hypervisor host is node2', log)
+        hypervisors = self.api.api_get('/os-hypervisors').body['hypervisors']
+        self.assertEqual(1, len(hypervisors), hypervisors)
+        self.assertEqual('node1', hypervisors[0]['hypervisor_hostname'])
+        # But the node2 ComputeNode is still in the database with deleted!=0.
+        with utils.temporary_mutation(ctxt, read_deleted='yes'):
+            cn = objects.ComputeNode.get_by_host_and_nodename(
+                ctxt, 'node1', 'node2')
+            self.assertTrue(cn.deleted)
+        # Now stub the driver again to report node2 as being back and run
+        # the periodic task.
+        compute.manager.driver._nodes = ['node1', 'node2']
+        LOG.info('Running update_available_resource which should bring back '
+                 'node2.')
+        compute.manager.update_available_resource(ctxt)
+        # The DBDuplicateEntry error should have been handled and resulted in
+        # updating the (soft) deleted record to no longer be deleted.
+        log = self.stdlog.logger.output
+        self.assertNotIn('DBDuplicateEntry', log)
+        # Should have two reported hypervisors again.
+        hypervisors = self.api.api_get('/os-hypervisors').body['hypervisors']
+        self.assertEqual(2, len(hypervisors), hypervisors)
+        # Now that the node2 record was un-soft-deleted, archiving should not
+        # remove any compute_nodes.
+        LOG.info('Archiving the database.')
+        archived = db_api.archive_deleted_rows(1000)[0]
+        self.assertNotIn('compute_nodes', archived)
+        cn2 = objects.ComputeNode.get_by_host_and_nodename(
+            ctxt, 'node1', 'node2')
+        self.assertFalse(cn2.deleted)
+        self.assertIsNone(cn2.deleted_at)
+        # The node2 id and uuid should not have changed in the DB.
+        self.assertEqual(cn.id, cn2.id)
+        self.assertEqual(cn.uuid, cn2.uuid)
diff --git a/nova/tests/unit/compute/test_resource_tracker.py b/nova/tests/unit/compute/test_resource_tracker.py
@@ -1074,56 +1074,45 @@ def fake_get_all(_ctx, nodename):
         self.assertEqual(_HOSTNAME, self.rt.compute_nodes[_NODENAME].host)
 
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
-    @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
-                return_value=objects.PciDeviceList(objects=[]))
     @mock.patch('nova.objects.ComputeNode.create')
     @mock.patch('nova.objects.ComputeNode.get_by_host_and_nodename')
     @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
                 '_update')
     def test_compute_node_created_on_empty(self, update_mock, get_mock,
-                                           create_mock, pci_tracker_mock,
+                                           create_mock,
                                            get_by_hypervisor_mock):
         get_by_hypervisor_mock.return_value = []
         self._test_compute_node_created(update_mock, get_mock, create_mock,
-                                        pci_tracker_mock,
                                         get_by_hypervisor_mock)
 
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
-    @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
-                return_value=objects.PciDeviceList(objects=[]))
     @mock.patch('nova.objects.ComputeNode.create')
     @mock.patch('nova.objects.ComputeNode.get_by_host_and_nodename')
     @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
                 '_update')
     def test_compute_node_created_on_empty_rebalance(self, update_mock,
                                                      get_mock,
                                                      create_mock,
-                                                     pci_tracker_mock,
                                                      get_by_hypervisor_mock):
         get_by_hypervisor_mock.return_value = []
         self._test_compute_node_created(update_mock, get_mock, create_mock,
-                                        pci_tracker_mock,
                                         get_by_hypervisor_mock,
                                         rebalances_nodes=True)
 
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
-    @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
-                return_value=objects.PciDeviceList(objects=[]))
     @mock.patch('nova.objects.ComputeNode.create')
     @mock.patch('nova.objects.ComputeNode.get_by_host_and_nodename')
     @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
                 '_update')
     def test_compute_node_created_too_many(self, update_mock, get_mock,
-                                           create_mock, pci_tracker_mock,
+                                           create_mock,
                                            get_by_hypervisor_mock):
         get_by_hypervisor_mock.return_value = ["fake_node_1", "fake_node_2"]
         self._test_compute_node_created(update_mock, get_mock, create_mock,
-                                        pci_tracker_mock,
                                         get_by_hypervisor_mock,
                                         rebalances_nodes=True)
 
-    def _test_compute_node_created(self, update_mock, get_mock,
-                                   create_mock, pci_tracker_mock,
+    def _test_compute_node_created(self, update_mock, get_mock, create_mock,
                                    get_by_hypervisor_mock,
                                    rebalances_nodes=False):
         self.flags(cpu_allocation_ratio=1.0, ram_allocation_ratio=1.0,
@@ -1152,12 +1141,12 @@ def _test_compute_node_created(self, update_mock, get_mock,
             'current_workload': 0,
             'vcpus': 4,
             'running_vms': 0,
-            'pci_passthrough_devices': '[]'
+            'pci_passthrough_devices': '[]',
+            'uuid': uuids.compute_node_uuid
         }
         # The expected compute represents the initial values used
         # when creating a compute node.
         expected_compute = objects.ComputeNode(
-            id=42,
             host_ip=resources['host_ip'],
             vcpus=resources['vcpus'],
             memory_mb=resources['memory_mb'],
@@ -1177,20 +1166,11 @@ def _test_compute_node_created(self, update_mock, get_mock,
             cpu_allocation_ratio=1.0,
             disk_allocation_ratio=1.0,
             stats={'failed_builds': 0},
-            pci_device_pools=objects.PciDevicePoolList(objects=[]),
             uuid=uuids.compute_node_uuid
         )
 
-        def set_cn_id():
-            # The PCI tracker needs the compute node's ID when starting up, so
-            # make sure that we set the ID value so we don't get a Cannot load
-            # 'id' in base class error
-            cn = self.rt.compute_nodes[_NODENAME]
-            cn.id = 42  # Has to be a number, not a mock
-            cn.uuid = uuids.compute_node_uuid
-
-        create_mock.side_effect = set_cn_id
-        self.rt._init_compute_node(mock.sentinel.ctx, resources)
+        with mock.patch.object(self.rt, '_setup_pci_tracker') as setup_pci:
+            self.rt._init_compute_node(mock.sentinel.ctx, resources)
 
         cn = self.rt.compute_nodes[_NODENAME]
         get_mock.assert_called_once_with(mock.sentinel.ctx, _HOSTNAME,
@@ -1202,22 +1182,47 @@ def set_cn_id():
             get_by_hypervisor_mock.assert_not_called()
         create_mock.assert_called_once_with()
         self.assertTrue(obj_base.obj_equal_prims(expected_compute, cn))
-        pci_tracker_mock.assert_called_once_with(mock.sentinel.ctx,
-                                                 42)
+        setup_pci.assert_called_once_with(mock.sentinel.ctx, cn, resources)
         self.assertFalse(update_mock.called)
 
+    @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
+                '_setup_pci_tracker')
+    @mock.patch('nova.objects.ComputeNode.get_by_host_and_nodename',
+                side_effect=exc.ComputeHostNotFound(host=_HOSTNAME))
+    @mock.patch('nova.objects.ComputeNode.create',
+                side_effect=(test.TestingException, None))
+    def test_compute_node_create_fail_retry_works(self, mock_create, mock_get,
+                                                  mock_setup_pci):
+        """Tests that _init_compute_node will not save the ComputeNode object
+        in the compute_nodes dict if create() fails.
+        """
+        self._setup_rt()
+        self.assertEqual({}, self.rt.compute_nodes)
+        ctxt = context.get_context()
+        # The first ComputeNode.create fails so rt.compute_nodes should
+        # remain empty.
+        resources = copy.deepcopy(_VIRT_DRIVER_AVAIL_RESOURCES)
+        resources['uuid'] = uuids.cn_uuid  # for the LOG.info message
+        self.assertRaises(test.TestingException,
+                          self.rt._init_compute_node, ctxt, resources)
+        self.assertEqual({}, self.rt.compute_nodes)
+        # Second create works so compute_nodes should have a mapping.
+        self.rt._init_compute_node(ctxt, resources)
+        self.assertIn(_NODENAME, self.rt.compute_nodes)
+        mock_get.assert_has_calls([mock.call(
+            ctxt, _HOSTNAME, _NODENAME)] * 2)
+        self.assertEqual(2, mock_create.call_count)
+        mock_setup_pci.assert_called_once_with(
+            ctxt, test.MatchType(objects.ComputeNode), resources)
+
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
-    @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
-                return_value=objects.PciDeviceList(objects=[]))
     @mock.patch('nova.objects.ComputeNode.create')
     @mock.patch('nova.objects.ComputeNode.get_by_host_and_nodename')
     @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
                 '_update')
     def test_node_removed(self, update_mock, get_mock,
-                          create_mock, pci_tracker_mock,
-                          get_by_hypervisor_mock):
+                          create_mock, get_by_hypervisor_mock):
         self._test_compute_node_created(update_mock, get_mock, create_mock,
-                                        pci_tracker_mock,
                                         get_by_hypervisor_mock)
         self.rt.old_resources[_NODENAME] = mock.sentinel.foo
         self.assertIn(_NODENAME, self.rt.compute_nodes)
diff --git a/nova/tests/unit/db/test_db_api.py b/nova/tests/unit/db/test_db_api.py
@@ -6882,6 +6882,18 @@ def test_compute_node_create(self):
         new_stats = jsonutils.loads(self.item['stats'])
         self.assertEqual(self.stats, new_stats)
 
+    def test_compute_node_create_duplicate_host_hypervisor_hostname(self):
+        """Tests to make sure that DBDuplicateEntry is raised when trying to
+        create a duplicate ComputeNode with the same host and
+        hypervisor_hostname values but different uuid values. This makes
+        sure that when _compute_node_get_and_update_deleted returns None
+        the DBDuplicateEntry is re-raised.
+        """
+        other_node = dict(self.compute_node_dict)
+        other_node['uuid'] = uuidutils.generate_uuid()
+        self.assertRaises(db_exc.DBDuplicateEntry,
+                          db.compute_node_create, self.ctxt, other_node)
+
     def test_compute_node_get_all(self):
         nodes = db.compute_node_get_all(self.ctxt)
         self.assertEqual(1, len(nodes))
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
@@ -27,6 +27,7 @@
 import contextlib
 import copy
 import time
+import uuid
 
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
@@ -674,6 +675,19 @@ class MediumFakeDriver(FakeDriver):
     local_gb = 1028
 
 
+class PredictableNodeUUIDDriver(SmallFakeDriver):
+    """SmallFakeDriver variant that reports a predictable node uuid in
+    get_available_resource, like IronicDriver.
+    """
+    def get_available_resource(self, nodename):
+        resources = super(
+            PredictableNodeUUIDDriver, self).get_available_resource(nodename)
+        # This is used in ComputeNode.update_from_virt_driver which is called
+        # from the ResourceTracker when creating a ComputeNode.
+        resources['uuid'] = uuid.uuid5(uuid.NAMESPACE_DNS, nodename)
+        return resources
+
+
 class FakeRescheduleDriver(FakeDriver):
     """FakeDriver derivative that triggers a reschedule on the first spawn
     attempt. This is expected to only be used in tests that have more than
