TaskManager: Only support single node locking

The multi-node locking is not used and there's no plan to use it.
Removing it allows us to clean up a lot of code.

The TaskManager tests are refactored to not use the DB.

Removed 'node' from get_node_mac_addresses() in driver/utils as it's
no longer needed.

Partial-Bug: 1312632

Change-Id: Ie3577ba150df6c84fc34a4b08775e5011f8925cb

9 files changed, 452 insertions, 483 deletions

diff --git a/ironic/tests/conductor/test_task_manager.py b/ironic/tests/conductor/test_task_manager.py
index 230e708be..1643348e4 100644
--- a/ironic/tests/conductor/test_task_manager.py
+++ b/ironic/tests/conductor/test_task_manager.py
@@ -17,169 +17,256 @@
 
 """Tests for :class:`ironic.conductor.task_manager`."""
 
-from testtools import matchers
-
 import eventlet
 from eventlet import greenpool
 import mock
 
 from ironic.common import driver_factory
 from ironic.common import exception
-from ironic.common import utils as ironic_utils
 from ironic.conductor import task_manager
 from ironic.db import api as dbapi
 from ironic import objects
-from ironic.openstack.common import context
-
 from ironic.tests import base as tests_base
-from ironic.tests.conductor import utils as mgr_utils
-from ironic.tests.db import base as db_base
-from ironic.tests.objects import utils as obj_utils
 
 
-def create_fake_node(ctxt, i):
-    node = obj_utils.create_test_node(ctxt,
-                                      id=i,
-                                      uuid=ironic_utils.generate_uuid())
-    return node.uuid
+@mock.patch.object(objects.Node, 'get')
+@mock.patch.object(dbapi.IMPL, 'release_node')
+@mock.patch.object(dbapi.IMPL, 'reserve_node')
+@mock.patch.object(driver_factory, 'get_driver')
+@mock.patch.object(dbapi.IMPL, 'get_ports_by_node_id')
+class TaskManagerTestCase(tests_base.TestCase):
+    def setUp(self):
+        super(TaskManagerTestCase, self).setUp()
+        self.host = 'test-host'
+        self.config(host=self.host)
+        self.context = mock.sentinel.context
+        self.node = mock.Mock(spec_set=objects.Node)
+
+    def test_excl_lock(self, get_ports_mock, get_driver_mock,
+                       reserve_mock, release_mock, node_get_mock):
+        reserve_mock.return_value = self.node
+        with task_manager.TaskManager(self.context, 'fake-node-id') as task:
+            self.assertEqual(self.context, task.context)
+            self.assertEqual(self.node, task.node)
+            self.assertEqual(get_ports_mock.return_value, task.ports)
+            self.assertEqual(get_driver_mock.return_value, task.driver)
+            self.assertFalse(task.shared)
+
+        reserve_mock.assert_called_once_with(self.host, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with(self.node.driver)
+        release_mock.assert_called_once_with(self.host, self.node.id)
+        self.assertFalse(node_get_mock.called)
+
+    def test_excl_lock_with_driver(self, get_ports_mock, get_driver_mock,
+                                   reserve_mock, release_mock,
+                                   node_get_mock):
+        reserve_mock.return_value = self.node
+        with task_manager.TaskManager(self.context, 'fake-node-id',
+                                      driver_name='fake-driver') as task:
+            self.assertEqual(self.context, task.context)
+            self.assertEqual(self.node, task.node)
+            self.assertEqual(get_ports_mock.return_value, task.ports)
+            self.assertEqual(get_driver_mock.return_value, task.driver)
+            self.assertFalse(task.shared)
+
+        reserve_mock.assert_called_once_with(self.host, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with('fake-driver')
+        release_mock.assert_called_once_with(self.host, self.node.id)
+        self.assertFalse(node_get_mock.called)
+
+    def test_excl_nested_acquire(self, get_ports_mock, get_driver_mock,
+                                 reserve_mock, release_mock,
+                                 node_get_mock):
+        node2 = mock.Mock(spec_set=objects.Node)
+
+        reserve_mock.return_value = self.node
+        get_ports_mock.return_value = mock.sentinel.ports1
+        get_driver_mock.return_value = mock.sentinel.driver1
+
+        with task_manager.TaskManager(self.context, 'node-id1') as task:
+            reserve_mock.return_value = node2
+            get_ports_mock.return_value = mock.sentinel.ports2
+            get_driver_mock.return_value = mock.sentinel.driver2
+            with task_manager.TaskManager(self.context, 'node-id2') as task2:
+                self.assertEqual(self.context, task.context)
+                self.assertEqual(self.node, task.node)
+                self.assertEqual(mock.sentinel.ports1, task.ports)
+                self.assertEqual(mock.sentinel.driver1, task.driver)
+                self.assertFalse(task.shared)
+                self.assertEqual(self.context, task2.context)
+                self.assertEqual(node2, task2.node)
+                self.assertEqual(mock.sentinel.ports2, task2.ports)
+                self.assertEqual(mock.sentinel.driver2, task2.driver)
+                self.assertFalse(task2.shared)
+
+        self.assertEqual([mock.call(self.host, 'node-id1'),
+                          mock.call(self.host, 'node-id2')],
+                         reserve_mock.call_args_list)
+        self.assertEqual([mock.call(self.node.id), mock.call(node2.id)],
+                         get_ports_mock.call_args_list)
+        self.assertEqual([mock.call(self.node.driver),
+                          mock.call(node2.driver)],
+                         get_driver_mock.call_args_list)
+        # release should be in reverse order
+        self.assertEqual([mock.call(self.host, node2.id),
+                          mock.call(self.host, self.node.id)],
+                         release_mock.call_args_list)
+        self.assertFalse(node_get_mock.called)
+
+    def test_excl_lock_reserve_exception(self, get_ports_mock,
+                                         get_driver_mock, reserve_mock,
+                                         release_mock, node_get_mock):
+        reserve_mock.side_effect = exception.NodeLocked(node='foo',
+                                                        host='foo')
 
+        self.assertRaises(exception.NodeLocked,
+                          task_manager.TaskManager,
+                          self.context,
+                          'fake-node-id')
 
-def ContainsUUIDs(uuids):
-    def _task_uuids(task):
-        return sorted([r.node.uuid for r in task.resources])
+        reserve_mock.assert_called_once_with(self.host, 'fake-node-id')
+        self.assertFalse(get_ports_mock.called)
+        self.assertFalse(get_driver_mock.called)
+        self.assertFalse(release_mock.called)
+        self.assertFalse(node_get_mock.called)
 
-    return matchers.AfterPreprocessing(
-            _task_uuids, matchers.Equals(uuids))
+    def test_excl_lock_get_ports_exception(self, get_ports_mock,
+                                           get_driver_mock, reserve_mock,
+                                           release_mock, node_get_mock):
+        reserve_mock.return_value = self.node
+        get_ports_mock.side_effect = exception.IronicException('foo')
 
+        self.assertRaises(exception.IronicException,
+                          task_manager.TaskManager,
+                          self.context,
+                          'fake-node-id')
 
-class TaskManagerSetup(db_base.DbTestCase):
+        reserve_mock.assert_called_once_with(self.host, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        self.assertFalse(get_driver_mock.called)
+        release_mock.assert_called_once_with(self.host, self.node.id)
+        self.assertFalse(node_get_mock.called)
 
-    def setUp(self):
-        super(TaskManagerSetup, self).setUp()
-        self.dbapi = dbapi.get_instance()
-        self.context = context.get_admin_context()
-        mgr_utils.mock_the_extension_manager()
-        self.driver = driver_factory.get_driver("fake")
-        self.config(host='test-host')
+    def test_excl_lock_get_driver_exception(self, get_ports_mock,
+                                            get_driver_mock, reserve_mock,
+                                            release_mock, node_get_mock):
+        reserve_mock.return_value = self.node
+        get_driver_mock.side_effect = exception.DriverNotFound(
+                driver_name='foo')
 
+        self.assertRaises(exception.DriverNotFound,
+                          task_manager.TaskManager,
+                          self.context,
+                          'fake-node-id')
+
+        reserve_mock.assert_called_once_with(self.host, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with(self.node.driver)
+        release_mock.assert_called_once_with(self.host, self.node.id)
+        self.assertFalse(node_get_mock.called)
+
+    def test_shared_lock(self, get_ports_mock, get_driver_mock,
+                         reserve_mock, release_mock, node_get_mock):
+        node_get_mock.return_value = self.node
+        with task_manager.TaskManager(self.context, 'fake-node-id',
+                                      shared=True) as task:
+            self.assertEqual(self.context, task.context)
+            self.assertEqual(self.node, task.node)
+            self.assertEqual(get_ports_mock.return_value, task.ports)
+            self.assertEqual(get_driver_mock.return_value, task.driver)
+            self.assertTrue(task.shared)
+
+        self.assertFalse(reserve_mock.called)
+        self.assertFalse(release_mock.called)
+        node_get_mock.assert_called_once_with(self.context, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with(self.node.driver)
+
+    def test_shared_lock_with_driver(self, get_ports_mock, get_driver_mock,
+                                     reserve_mock, release_mock,
+                                     node_get_mock):
+        node_get_mock.return_value = self.node
+        with task_manager.TaskManager(self.context,
+                                      'fake-node-id',
+                                      shared=True,
+                                      driver_name='fake-driver') as task:
+            self.assertEqual(self.context, task.context)
+            self.assertEqual(self.node, task.node)
+            self.assertEqual(get_ports_mock.return_value, task.ports)
+            self.assertEqual(get_driver_mock.return_value, task.driver)
+            self.assertTrue(task.shared)
+
+        self.assertFalse(reserve_mock.called)
+        self.assertFalse(release_mock.called)
+        node_get_mock.assert_called_once_with(self.context, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with('fake-driver')
 
-class TaskManagerTestCase(TaskManagerSetup):
+    def test_shared_lock_node_get_exception(self, get_ports_mock,
+                                            get_driver_mock, reserve_mock,
+                                            release_mock, node_get_mock):
+        node_get_mock.side_effect = exception.NodeNotFound(node='foo')
 
-    def setUp(self):
-        super(TaskManagerTestCase, self).setUp()
-        self.uuids = [create_fake_node(self.context, i) for i in range(1, 6)]
-        self.uuids.sort()
-
-    def test_task_manager_gets_node(self):
-        node_uuid = self.uuids[0]
-        task = task_manager.TaskManager(self.context, node_uuid)
-        self.assertEqual(node_uuid, task.node.uuid)
-
-    def test_task_manager_updates_db(self):
-        node_uuid = self.uuids[0]
-        node = objects.Node.get_by_uuid(self.context, node_uuid)
-        self.assertIsNone(node.reservation)
-
-        with task_manager.acquire(self.context, node_uuid) as task:
-            self.assertEqual(node.uuid, task.node.uuid)
-            node.refresh(self.context)
-            self.assertEqual('test-host', node.reservation)
-
-        node.refresh(self.context)
-        self.assertIsNone(node.reservation)
-
-    def test_get_many_nodes(self):
-        uuids = self.uuids[1:3]
-
-        with task_manager.acquire(self.context, uuids) as task:
-            self.assertThat(task, ContainsUUIDs(uuids))
-            for node in [r.node for r in task.resources]:
-                self.assertEqual('test-host', node.reservation)
-
-        # Ensure all reservations are cleared
-        for uuid in self.uuids:
-            node = objects.Node.get_by_uuid(self.context, uuid)
-            self.assertIsNone(node.reservation)
-
-    def test_get_nodes_nested(self):
-        uuids = self.uuids[0:2]
-        more_uuids = self.uuids[3:4]
-
-        with task_manager.acquire(self.context, uuids) as task:
-            self.assertThat(task, ContainsUUIDs(uuids))
-            with task_manager.acquire(self.context,
-                                      more_uuids) as another_task:
-                self.assertThat(another_task, ContainsUUIDs(more_uuids))
-
-    def test_get_shared_lock(self):
-        uuids = self.uuids[0:2]
-
-        # confirm we can elevate from shared -> exclusive
-        with task_manager.acquire(self.context, uuids, shared=True) as task:
-            self.assertThat(task, ContainsUUIDs(uuids))
-            with task_manager.acquire(self.context, uuids,
-                                      shared=False) as inner_task:
-                self.assertThat(inner_task, ContainsUUIDs(uuids))
-
-        # confirm someone else can still get a shared lock
-        with task_manager.acquire(self.context, uuids, shared=False) as task:
-            self.assertThat(task, ContainsUUIDs(uuids))
-            with task_manager.acquire(self.context, uuids,
-                                      shared=True) as inner_task:
-                self.assertThat(inner_task, ContainsUUIDs(uuids))
-
-    def test_get_one_node_already_locked(self):
-        node_uuid = self.uuids[0]
-        task_manager.TaskManager(self.context, node_uuid)
-
-        # Check that db node reservation is still set
-        # if another TaskManager attempts to acquire the same node
-        self.assertRaises(exception.NodeLocked,
+        self.assertRaises(exception.NodeNotFound,
                           task_manager.TaskManager,
-                          self.context, node_uuid)
-        node = objects.Node.get_by_uuid(self.context, node_uuid)
-        self.assertEqual('test-host', node.reservation)
+                          self.context,
+                          'fake-node-id',
+                          shared=True)
+
+        self.assertFalse(reserve_mock.called)
+        self.assertFalse(release_mock.called)
+        node_get_mock.assert_called_once_with(self.context, 'fake-node-id')
+        self.assertFalse(get_ports_mock.called)
+        self.assertFalse(get_driver_mock.called)
 
-    def test_get_many_nodes_some_already_locked(self):
-        unlocked_node_uuids = self.uuids[0:2] + self.uuids[3:5]
-        locked_node_uuid = self.uuids[2]
-        task_manager.TaskManager(self.context, locked_node_uuid)
+    def test_shared_lock_get_ports_exception(self, get_ports_mock,
+                                             get_driver_mock, reserve_mock,
+                                             release_mock, node_get_mock):
+        node_get_mock.return_value = self.node
+        get_ports_mock.side_effect = exception.IronicException('foo')
 
-        # Check that none of the other nodes are reserved
-        # and the one which we first locked has not been unlocked
-        self.assertRaises(exception.NodeLocked,
+        self.assertRaises(exception.IronicException,
                           task_manager.TaskManager,
                           self.context,
-                          self.uuids)
-        node = objects.Node.get_by_uuid(self.context, locked_node_uuid)
-        self.assertEqual('test-host', node.reservation)
-        for uuid in unlocked_node_uuids:
-            node = objects.Node.get_by_uuid(self.context, uuid)
-            self.assertIsNone(node.reservation)
-
-    def test_get_one_node_driver_load_exception(self):
-        node_uuid = self.uuids[0]
+                          'fake-node-id',
+                          shared=True)
+
+        self.assertFalse(reserve_mock.called)
+        self.assertFalse(release_mock.called)
+        node_get_mock.assert_called_once_with(self.context, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        self.assertFalse(get_driver_mock.called)
+
+    def test_shared_lock_get_driver_exception(self, get_ports_mock,
+                                              get_driver_mock, reserve_mock,
+                                              release_mock, node_get_mock):
+        node_get_mock.return_value = self.node
+        get_driver_mock.side_effect = exception.DriverNotFound(
+                driver_name='foo')
+
         self.assertRaises(exception.DriverNotFound,
                           task_manager.TaskManager,
-                          self.context, node_uuid,
-                          driver_name='no-such-driver')
-
-        # Check that db node reservation is not set.
-        node = objects.Node.get_by_uuid(self.context, node_uuid)
-        self.assertIsNone(node.reservation)
-
-    @mock.patch.object(driver_factory, 'get_driver')
-    @mock.patch.object(dbapi.IMPL, 'get_ports_by_node_id')
-    @mock.patch.object(dbapi.IMPL, 'reserve_nodes')
-    def test_spawn_after(self, reserve_mock, get_ports_mock,
-                         get_driver_mock):
+                          self.context,
+                          'fake-node-id',
+                          shared=True)
+
+        self.assertFalse(reserve_mock.called)
+        self.assertFalse(release_mock.called)
+        node_get_mock.assert_called_once_with(self.context, 'fake-node-id')
+        get_ports_mock.assert_called_once_with(self.node.id)
+        get_driver_mock.assert_called_once_with(self.node.driver)
+
+    def test_spawn_after(self, get_ports_mock, get_driver_mock,
+                         reserve_mock, release_mock, node_get_mock):
         thread_mock = mock.Mock(spec_set=['link', 'cancel'])
         spawn_mock = mock.Mock(return_value=thread_mock)
-        release_mock = mock.Mock()
+        task_release_mock = mock.Mock()
 
         with task_manager.TaskManager(self.context, 'node-id') as task:
             task.spawn_after(spawn_mock, 1, 2, foo='bar', cat='meow')
-            task.release_resources = release_mock
+            task.release_resources = task_release_mock
 
         spawn_mock.assert_called_once_with(1, 2, foo='bar', cat='meow')
         thread_mock.link.assert_called_once_with(
@@ -188,139 +275,105 @@ class TaskManagerTestCase(TaskManagerSetup):
         # Since we mocked link(), we're testing that __exit__ didn't
         # release resources pending the finishing of the background
         # thread
-        self.assertFalse(release_mock.called)
+        self.assertFalse(task_release_mock.called)
 
-    @mock.patch.object(driver_factory, 'get_driver')
-    @mock.patch.object(dbapi.IMPL, 'get_ports_by_node_id')
-    @mock.patch.object(dbapi.IMPL, 'reserve_nodes')
-    def test_spawn_after_exception_while_yielded(self, reserve_mock,
-                                                 get_ports_mock,
-                                                 get_driver_mock):
+    def test_spawn_after_exception_while_yielded(self, get_ports_mock,
+                                                 get_driver_mock,
+                                                 reserve_mock,
+                                                 release_mock,
+                                                 node_get_mock):
         spawn_mock = mock.Mock()
-        release_mock = mock.Mock()
+        task_release_mock = mock.Mock()
 
         def _test_it():
             with task_manager.TaskManager(self.context, 'node-id') as task:
                 task.spawn_after(spawn_mock, 1, 2, foo='bar', cat='meow')
-                task.release_resources = release_mock
+                task.release_resources = task_release_mock
                 raise exception.IronicException('foo')
 
         self.assertRaises(exception.IronicException, _test_it)
         self.assertFalse(spawn_mock.called)
-        release_mock.assert_called_once_with()
+        task_release_mock.assert_called_once_with()
 
-    @mock.patch.object(driver_factory, 'get_driver')
-    @mock.patch.object(dbapi.IMPL, 'get_ports_by_node_id')
-    @mock.patch.object(dbapi.IMPL, 'reserve_nodes')
-    def test_spawn_after_spawn_fails(self, reserve_mock, get_ports_mock,
-                                     get_driver_mock):
+    def test_spawn_after_spawn_fails(self, get_ports_mock, get_driver_mock,
+                                     reserve_mock, release_mock,
+                                     node_get_mock):
         spawn_mock = mock.Mock(side_effect=exception.IronicException('foo'))
-        release_mock = mock.Mock()
+        task_release_mock = mock.Mock()
 
         def _test_it():
             with task_manager.TaskManager(self.context, 'node-id') as task:
                 task.spawn_after(spawn_mock, 1, 2, foo='bar', cat='meow')
-                task.release_resources = release_mock
+                task.release_resources = task_release_mock
 
         self.assertRaises(exception.IronicException, _test_it)
 
         spawn_mock.assert_called_once_with(1, 2, foo='bar', cat='meow')
-        release_mock.assert_called_once_with()
+        task_release_mock.assert_called_once_with()
 
-    @mock.patch.object(driver_factory, 'get_driver')
-    @mock.patch.object(dbapi.IMPL, 'get_ports_by_node_id')
-    @mock.patch.object(dbapi.IMPL, 'reserve_nodes')
-    def test_spawn_after_link_fails(self, reserve_mock, get_ports_mock,
-                                     get_driver_mock):
+    def test_spawn_after_link_fails(self, get_ports_mock, get_driver_mock,
+                                    reserve_mock, release_mock,
+                                    node_get_mock):
         thread_mock = mock.Mock(spec_set=['link', 'cancel'])
         thread_mock.link.side_effect = exception.IronicException('foo')
         spawn_mock = mock.Mock(return_value=thread_mock)
-        release_mock = mock.Mock()
+        task_release_mock = mock.Mock()
         thr_release_mock = mock.Mock(spec_set=[])
 
         def _test_it():
             with task_manager.TaskManager(self.context, 'node-id') as task:
                 task.spawn_after(spawn_mock, 1, 2, foo='bar', cat='meow')
                 task._thread_release_resources = thr_release_mock
-                task.release_resources = release_mock
+                task.release_resources = task_release_mock
 
         self.assertRaises(exception.IronicException, _test_it)
 
         spawn_mock.assert_called_once_with(1, 2, foo='bar', cat='meow')
         thread_mock.link.assert_called_once_with(thr_release_mock)
         thread_mock.cancel.assert_called_once_with()
-        release_mock.assert_called_once_with()
+        task_release_mock.assert_called_once_with()
+
 
+@task_manager.require_exclusive_lock
+def _req_excl_lock_method(*args, **kwargs):
+    return (args, kwargs)
 
-class ExclusiveLockDecoratorTestCase(TaskManagerSetup):
 
+class ExclusiveLockDecoratorTestCase(tests_base.TestCase):
     def setUp(self):
         super(ExclusiveLockDecoratorTestCase, self).setUp()
-        self.uuids = [create_fake_node(self.context, 123)]
-
-    def test_require_exclusive_lock(self):
-        @task_manager.require_exclusive_lock
-        def do_state_change(task):
-            for r in task.resources:
-                task.dbapi.update_node(r.node.uuid,
-                                       {'power_state': 'test-state'})
-
-        with task_manager.acquire(self.context, self.uuids,
-                                  shared=True) as task:
-            self.assertRaises(exception.ExclusiveLockRequired,
-                              do_state_change,
-                              task)
-
-        with task_manager.acquire(self.context, self.uuids,
-                                  shared=False) as task:
-            do_state_change(task)
-
-        for uuid in self.uuids:
-            res = objects.Node.get_by_uuid(self.context, uuid)
-            self.assertEqual('test-state', res.power_state)
-
-    @task_manager.require_exclusive_lock
-    def _do_state_change(self, task):
-        for r in task.resources:
-            task.dbapi.update_node(r.node.uuid,
-                                   {'power_state': 'test-state'})
-
-    def test_require_exclusive_lock_on_object(self):
-        with task_manager.acquire(self.context, self.uuids,
-                                  shared=True) as task:
-            self.assertRaises(exception.ExclusiveLockRequired,
-                              self._do_state_change,
-                              task)
-
-        with task_manager.acquire(self.context, self.uuids,
-                                  shared=False) as task:
-            self._do_state_change(task)
-
-        for uuid in self.uuids:
-            res = objects.Node.get_by_uuid(self.context, uuid)
-            self.assertEqual('test-state', res.power_state)
-
-    def test_one_node_per_task_properties(self):
-        with task_manager.acquire(self.context, self.uuids) as task:
-            self.assertEqual(task.node, task.resources[0].node)
-            self.assertEqual(task.driver, task.resources[0].driver)
-            self.assertEqual(task.node_manager, task.resources[0])
-
-    def test_one_node_per_task_properties_fail(self):
-        self.uuids.append(create_fake_node(self.context, 456))
-        with task_manager.acquire(self.context, self.uuids) as task:
-            def get_node():
-                return task.node
-
-            def get_driver():
-                return task.driver
-
-            def get_node_manager():
-                return task.node_manager
-
-            self.assertRaises(AttributeError, get_node)
-            self.assertRaises(AttributeError, get_driver)
-            self.assertRaises(AttributeError, get_node_manager)
+        self.task = mock.Mock(spec=task_manager.TaskManager)
+        self.args_task_first = (self.task, 1, 2)
+        self.args_task_second = (1, self.task, 2)
+        self.kwargs = dict(cat='meow', dog='wuff')
+
+    def test_with_excl_lock_task_first_arg(self):
+        self.task.shared = False
+        (args, kwargs) = _req_excl_lock_method(*self.args_task_first,
+                                               **self.kwargs)
+        self.assertEqual(self.args_task_first, args)
+        self.assertEqual(self.kwargs, kwargs)
+
+    def test_with_excl_lock_task_second_arg(self):
+        self.task.shared = False
+        (args, kwargs) = _req_excl_lock_method(*self.args_task_second,
+                                               **self.kwargs)
+        self.assertEqual(self.args_task_second, args)
+        self.assertEqual(self.kwargs, kwargs)
+
+    def test_with_shared_lock_task_first_arg(self):
+        self.task.shared = True
+        self.assertRaises(exception.ExclusiveLockRequired,
+                          _req_excl_lock_method,
+                          *self.args_task_first,
+                          **self.kwargs)
+
+    def test_with_shared_lock_task_second_arg(self):
+        self.task.shared = True
+        self.assertRaises(exception.ExclusiveLockRequired,
+                          _req_excl_lock_method,
+                          *self.args_task_second,
+                          **self.kwargs)
 
 
 class TaskManagerGreenThreadTestCase(tests_base.TestCase):
diff --git a/ironic/tests/db/test_nodes.py b/ironic/tests/db/test_nodes.py
index 239621c95..488569fec 100644
--- a/ironic/tests/db/test_nodes.py
+++ b/ironic/tests/db/test_nodes.py
@@ -40,36 +40,6 @@ class DbNodeTestCase(base.DbTestCase):
         self.dbapi.create_node(n)
         return n
 
-    def _create_many_test_nodes(self):
-        uuids = []
-        for i in range(1, 6):
-            n = self._create_test_node(id=i, uuid=ironic_utils.generate_uuid())
-            uuids.append(n['uuid'])
-        uuids.sort()
-        return uuids
-
-    def _create_associated_nodes(self):
-        uuids = []
-        uuids_with_instance = []
-
-        for i in range(1, 5):
-            uuid = ironic_utils.generate_uuid()
-            uuids.append(six.text_type(uuid))
-            if i < 3:
-                instance_uuid = ironic_utils.generate_uuid()
-                uuids_with_instance.append(six.text_type(uuid))
-            else:
-                instance_uuid = None
-
-            n = utils.get_test_node(id=i,
-                                    uuid=uuid,
-                                    instance_uuid=instance_uuid)
-            self.dbapi.create_node(n)
-
-        uuids.sort()
-        uuids_with_instance.sort()
-        return (uuids, uuids_with_instance)
-
     def test_create_node(self):
         self._create_test_node()
 
@@ -353,14 +323,14 @@ class DbNodeTestCase(base.DbTestCase):
         res = self.dbapi.update_node(n['id'], {'extra': {'foo': 'bar'}})
         self.assertIsNone(res['provision_updated_at'])
 
-    def test_reserve_one_node(self):
+    def test_reserve_node(self):
         n = self._create_test_node()
         uuid = n['uuid']
 
         r1 = 'fake-reservation'
 
         # reserve the node
-        self.dbapi.reserve_nodes(r1, [uuid])
+        self.dbapi.reserve_node(r1, uuid)
 
         # check reservation
         res = self.dbapi.get_node_by_uuid(uuid)
@@ -371,10 +341,10 @@ class DbNodeTestCase(base.DbTestCase):
         uuid = n['uuid']
 
         r1 = 'fake-reservation'
-        self.dbapi.reserve_nodes(r1, [uuid])
+        self.dbapi.reserve_node(r1, uuid)
 
         # release reservation
-        self.dbapi.release_nodes(r1, [uuid])
+        self.dbapi.release_node(r1, uuid)
         res = self.dbapi.get_node_by_uuid(uuid)
         self.assertIsNone(res.reservation)
 
@@ -386,15 +356,15 @@ class DbNodeTestCase(base.DbTestCase):
         r2 = 'another-reservation'
 
         # reserve the node
-        self.dbapi.reserve_nodes(r1, [uuid])
+        self.dbapi.reserve_node(r1, uuid)
 
         # another host fails to reserve or release
         self.assertRaises(exception.NodeLocked,
-                          self.dbapi.reserve_nodes,
-                          r2, [uuid])
+                          self.dbapi.reserve_node,
+                          r2, uuid)
         self.assertRaises(exception.NodeLocked,
-                          self.dbapi.release_nodes,
-                          r2, [uuid])
+                          self.dbapi.release_node,
+                          r2, uuid)
 
     def test_reservation_after_release(self):
         n = self._create_test_node()
@@ -403,94 +373,48 @@ class DbNodeTestCase(base.DbTestCase):
         r1 = 'fake-reservation'
         r2 = 'another-reservation'
 
-        self.dbapi.reserve_nodes(r1, [uuid])
-        self.dbapi.release_nodes(r1, [uuid])
+        self.dbapi.reserve_node(r1, uuid)
+        self.dbapi.release_node(r1, uuid)
 
         # another host succeeds
-        self.dbapi.reserve_nodes(r2, [uuid])
+        self.dbapi.reserve_node(r2, uuid)
         res = self.dbapi.get_node_by_uuid(uuid)
         self.assertEqual(r2, res.reservation)
 
-    def test_reserve_many_nodes(self):
-        uuids = self._create_many_test_nodes()
-        r1 = 'first-reservation'
-
-        self.dbapi.reserve_nodes(r1, uuids)
-
-        for uuid in uuids:
-            res = self.dbapi.get_node_by_uuid(uuid)
-            self.assertEqual(r1, res.reservation)
-
-    def test_reserve_overlaping_ranges_fails(self):
-        uuids = self._create_many_test_nodes()
-
-        r1 = 'first-reservation'
-        r2 = 'second-reservation'
-
-        self.dbapi.reserve_nodes(r1, uuids[:3])
-
-        self.assertRaises(exception.NodeLocked,
-                          self.dbapi.reserve_nodes,
-                          r2, uuids)
-        self.assertRaises(exception.NodeLocked,
-                          self.dbapi.reserve_nodes,
-                          r2, uuids[2:])
-
-    def test_reserve_non_overlaping_ranges(self):
-        uuids = self._create_many_test_nodes()
-
-        r1 = 'first-reservation'
-        r2 = 'second-reservation'
-
-        self.dbapi.reserve_nodes(r1, uuids[:3])
-        self.dbapi.reserve_nodes(r2, uuids[3:])
-
-        for i in range(0, len(uuids)):
-            res = self.dbapi.get_node_by_uuid(uuids[i])
-
-            reservation = r1 if i < 3 else r2
-            self.assertEqual(reservation, res.reservation)
-
-    def test_reserve_empty(self):
-        self.assertRaises(exception.InvalidIdentity,
-                          self.dbapi.reserve_nodes, 'reserv1', [])
-
     def test_reservation_in_exception_message(self):
         n = self._create_test_node()
         uuid = n['uuid']
 
         r = 'fake-reservation'
-        self.dbapi.reserve_nodes(r, [uuid])
+        self.dbapi.reserve_node(r, uuid)
         try:
-            self.dbapi.reserve_nodes('another', [uuid])
+            self.dbapi.reserve_node('another', uuid)
         except exception.NodeLocked as e:
             self.assertIn(r, str(e))
 
-    def test_release_overlaping_ranges_fails(self):
-        uuids = self._create_many_test_nodes()
-
-        r1 = 'first-reservation'
-        r2 = 'second-reservation'
-
-        self.dbapi.reserve_nodes(r1, uuids[:3])
-        self.dbapi.reserve_nodes(r2, uuids[3:])
-
-        self.assertRaises(exception.NodeLocked,
-                          self.dbapi.release_nodes,
-                          r1, uuids)
+    def test_reservation_non_existent_node(self):
+        n = self._create_test_node()
+        self.dbapi.destroy_node(n['id'])
 
-    def test_release_non_ranges(self):
-        uuids = self._create_many_test_nodes()
+        self.assertRaises(exception.NodeNotFound,
+                          self.dbapi.reserve_node, 'fake', n['id'])
+        self.assertRaises(exception.NodeNotFound,
+                          self.dbapi.reserve_node, 'fake', n['uuid'])
 
-        r1 = 'first-reservation'
-        r2 = 'second-reservation'
+    def test_release_non_existent_node(self):
+        n = self._create_test_node()
+        self.dbapi.destroy_node(n['id'])
 
-        self.dbapi.reserve_nodes(r1, uuids[:3])
-        self.dbapi.reserve_nodes(r2, uuids[3:])
+        self.assertRaises(exception.NodeNotFound,
+                          self.dbapi.release_node, 'fake', n['id'])
+        self.assertRaises(exception.NodeNotFound,
+                          self.dbapi.release_node, 'fake', n['uuid'])
 
-        self.dbapi.release_nodes(r1, uuids[:3])
-        self.dbapi.release_nodes(r2, uuids[3:])
+    def test_release_non_locked_node(self):
+        n = self._create_test_node()
 
-        for uuid in uuids:
-            res = self.dbapi.get_node_by_uuid(uuid)
-            self.assertIsNone(res.reservation)
+        self.assertEqual(None, n['reservation'])
+        self.assertRaises(exception.NodeNotLocked,
+                          self.dbapi.release_node, 'fake', n['id'])
+        self.assertRaises(exception.NodeNotLocked,
+                          self.dbapi.release_node, 'fake', n['uuid'])
diff --git a/ironic/tests/db/test_ports.py b/ironic/tests/db/test_ports.py
index b129091f4..01dd07dee 100644
--- a/ironic/tests/db/test_ports.py
+++ b/ironic/tests/db/test_ports.py
@@ -99,7 +99,7 @@ class DbPortTestCase(base.DbTestCase):
     def test_destroy_port_on_reserved_node(self):
         p = self.dbapi.create_port(db_utils.get_test_port(node_id=self.n.id))
         uuid = self.n.uuid
-        self.dbapi.reserve_nodes('fake-reservation', [uuid])
+        self.dbapi.reserve_node('fake-reservation', uuid)
         self.assertRaises(exception.NodeLocked,
                           self.dbapi.destroy_port, p.id)
 
diff --git a/ironic/tests/drivers/test_ipminative.py b/ironic/tests/drivers/test_ipminative.py
index ff5ebe3ab..0ec04a236 100644
--- a/ironic/tests/drivers/test_ipminative.py
+++ b/ironic/tests/drivers/test_ipminative.py
@@ -172,7 +172,7 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
         power_on_mock.return_value = states.POWER_ON
 
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.driver.power.set_power_state(
                 task, states.POWER_ON)
         power_on_mock.assert_called_once_with(self.info)
@@ -182,7 +182,7 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
         power_off_mock.return_value = states.POWER_OFF
 
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.driver.power.set_power_state(
                 task, states.POWER_OFF)
         power_off_mock.assert_called_once_with(self.info)
@@ -194,7 +194,7 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
 
         self.config(retry_timeout=500, group='ipmi')
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.assertRaises(exception.PowerStateFailure,
                               self.driver.power.set_power_state,
                               task,
@@ -207,12 +207,12 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
         ipmicmd.set_bootdev.return_value = None
 
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.driver.vendor._set_boot_device(task, 'pxe')
         ipmicmd.set_bootdev.assert_called_once_with('pxe')
 
     def test_set_boot_device_bad_device(self):
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
+        with task_manager.acquire(self.context, self.node.uuid) as task:
             self.assertRaises(exception.InvalidParameterValue,
                     self.driver.vendor._set_boot_device,
                     task,
@@ -223,7 +223,7 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
         reboot_mock.return_value = None
 
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.driver.power.reboot(task)
         reboot_mock.assert_called_once_with(self.info)
 
@@ -234,7 +234,7 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
 
         self.config(retry_timeout=500, group='ipmi')
         with task_manager.acquire(self.context,
-                                  [self.node.uuid]) as task:
+                                  self.node.uuid) as task:
             self.assertRaises(exception.PowerStateFailure,
                               self.driver.power.reboot,
                               task)
@@ -242,14 +242,14 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
 
     def test_vendor_passthru_validate__set_boot_device_good(self):
         with task_manager.acquire(self.context,
-                                 [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.vendor.validate(task,
                                         method='set_boot_device',
                                         device='pxe')
 
     def test_vendor_passthru_val__set_boot_device_fail_unknown_device(self):
         with task_manager.acquire(self.context,
-                                 [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                               self.driver.vendor.validate,
                               task, method='set_boot_device',
@@ -257,21 +257,21 @@ class IPMINativeDriverTestCase(db_base.DbTestCase):
 
     def test_vendor_passthru_val__set_boot_device_fail_missed_device_arg(self):
         with task_manager.acquire(self.context,
-                                 [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                               self.driver.vendor.validate,
                               task, method='set_boot_device')
 
     def test_vendor_passthru_validate_method_notmatch(self):
         with task_manager.acquire(self.context,
-                                 [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                               self.driver.vendor.validate,
                               task, method='non-existent-method')
 
     @mock.patch.object(ipminative.VendorPassthru, '_set_boot_device')
     def test_vendor_passthru_call__set_boot_device(self, boot_mock):
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=False) as task:
             self.driver.vendor.vendor_passthru(task,
                                                method='set_boot_device',
diff --git a/ironic/tests/drivers/test_ipmitool.py b/ironic/tests/drivers/test_ipmitool.py
index 7907313ed..211ae3c39 100644
--- a/ironic/tests/drivers/test_ipmitool.py
+++ b/ironic/tests/drivers/test_ipmitool.py
@@ -306,7 +306,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
 
         mock_on.return_value = states.POWER_ON
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.power.set_power_state(task,
                                               states.POWER_ON)
 
@@ -321,7 +321,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         mock_off.return_value = states.POWER_OFF
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.power.set_power_state(task,
                                               states.POWER_OFF)
 
@@ -335,7 +335,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
 
         mock_on.return_value = states.ERROR
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.PowerStateFailure,
                               self.driver.power.set_power_state,
                               task,
@@ -345,7 +345,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         self.assertFalse(mock_off.called)
 
     def test_set_power_invalid_state(self):
-        with task_manager.acquire(self.context, [self.node['uuid']]) as task:
+        with task_manager.acquire(self.context, self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                     self.driver.power.set_power_state,
                     task,
@@ -356,13 +356,13 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         mock_exec.return_value = [None, None]
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.vendor._set_boot_device(task, 'pxe')
 
         mock_exec.assert_called_once_with(self.info, "chassis bootdev pxe")
 
     def test_set_boot_device_bad_device(self):
-        with task_manager.acquire(self.context, [self.node['uuid']]) as task:
+        with task_manager.acquire(self.context, self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                     self.driver.vendor._set_boot_device,
                     task,
@@ -380,7 +380,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
                     mock.call.power_on(self.info)]
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.power.reboot(task)
 
         self.assertEqual(manager.mock_calls, expected)
@@ -397,7 +397,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
                     mock.call.power_on(self.info)]
 
         with task_manager.acquire(self.context,
-                                 [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.PowerStateFailure,
                               self.driver.power.reboot,
                               task)
@@ -431,7 +431,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
 
     @mock.patch.object(ipmi.VendorPassthru, '_set_boot_device')
     def test_vendor_passthru_call_set_boot_device(self, boot_mock):
-        with task_manager.acquire(self.context, [self.node['uuid']],
+        with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=False) as task:
             self.driver.vendor.vendor_passthru(task,
                                                method='set_boot_device',
@@ -442,7 +442,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
     def test_validate_ok(self, exec_mock):
         exec_mock.return_value = ('System GUID: fake', '')
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             task.driver.power.validate(task, task.node)
             exec_mock.assert_called_once_with(mock.ANY, "mc guid")
 
@@ -450,7 +450,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
     def test_validate_fail(self, exec_mock):
         exec_mock.side_effect = Exception
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.InvalidParameterValue,
                               task.driver.power.validate, task,
                               task.node)
@@ -462,7 +462,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         mock_exec.return_value = None
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.console.start_console(task, self.node)
 
         mock_exec.assert_called_once_with(self.info['uuid'],
@@ -477,7 +477,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
                 error='error')
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.assertRaises(exception.ConsoleSubprocessFailed,
                               self.driver.console.start_console,
                               task, self.node)
@@ -488,7 +488,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         mock_exec.return_value = None
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             self.driver.console.stop_console(task, self.node)
 
         mock_exec.assert_called_once_with(self.info['uuid'])
@@ -502,7 +502,7 @@ class IPMIToolDriverTestCase(db_base.DbTestCase):
         expected = {'type': 'shellinabox', 'url': url}
 
         with task_manager.acquire(self.context,
-                                  [self.node['uuid']]) as task:
+                                  self.node['uuid']) as task:
             console_info = self.driver.console.get_console(task,
                                                            self.node)
 
diff --git a/ironic/tests/drivers/test_pxe.py b/ironic/tests/drivers/test_pxe.py
index e559cc5a0..288c72889 100644
--- a/ironic/tests/drivers/test_pxe.py
+++ b/ironic/tests/drivers/test_pxe.py
@@ -575,19 +575,19 @@ class PXEDriverTestCase(db_base.DbTestCase):
     def test_validate_good(self, mock_glance):
         mock_glance.return_value = {'properties': {'kernel_id': 'fake-kernel',
                                                    'ramdisk_id': 'fake-initr'}}
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
-            task.resources[0].driver.deploy.validate(task, self.node)
+            task.driver.deploy.validate(task, self.node)
 
     def test_validate_fail(self):
         info = dict(INFO_DICT)
         del info['pxe_image_source']
         self.node['driver_info'] = json.dumps(info)
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
             task.node['driver_info'] = json.dumps(info)
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.deploy.validate,
+                              task.driver.deploy.validate,
                               task, task.node)
 
     def test_validate_fail_no_port(self):
@@ -595,10 +595,10 @@ class PXEDriverTestCase(db_base.DbTestCase):
                 self.context,
                 id=321, uuid='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee',
                 driver='fake_pxe', driver_info=INFO_DICT)
-        with task_manager.acquire(self.context, [new_node.uuid],
+        with task_manager.acquire(self.context, new_node.uuid,
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.deploy.validate,
+                              task.driver.deploy.validate,
                               task, new_node)
 
     @mock.patch.object(base_image_service.BaseImageService, '_show')
@@ -610,9 +610,9 @@ class PXEDriverTestCase(db_base.DbTestCase):
         # not present in the keystone catalog
         mock_ks.side_effect = exception.CatalogFailure
 
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
-            task.resources[0].driver.deploy.validate(task, self.node)
+            task.driver.deploy.validate(task, self.node)
             self.assertFalse(mock_ks.called)
 
     @mock.patch.object(base_image_service.BaseImageService, '_show')
@@ -625,9 +625,9 @@ class PXEDriverTestCase(db_base.DbTestCase):
         # not present in the config file
         self.config(group='conductor', api_url=None)
 
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
-            task.resources[0].driver.deploy.validate(task, self.node)
+            task.driver.deploy.validate(task, self.node)
             mock_ks.assert_called_once_with()
 
     @mock.patch.object(keystone, 'get_service_url')
@@ -637,10 +637,10 @@ class PXEDriverTestCase(db_base.DbTestCase):
         # not present in the config file
         self.config(group='conductor', api_url=None)
 
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.deploy.validate,
+                              task.driver.deploy.validate,
                               task, self.node)
             mock_ks.assert_called_once_with()
 
@@ -676,25 +676,25 @@ class PXEDriverTestCase(db_base.DbTestCase):
                                   task, self.node)
 
     def test_vendor_passthru_validate_good(self):
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
-            task.resources[0].driver.vendor.validate(task,
-                    method='pass_deploy_info', address='123456', iqn='aaa-bbb',
-                    key='fake-56789')
+            task.driver.vendor.validate(task, method='pass_deploy_info',
+                                        address='123456', iqn='aaa-bbb',
+                                        key='fake-56789')
 
     def test_vendor_passthru_validate_fail(self):
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.validate,
+                              task.driver.vendor.validate,
                               task, method='pass_deploy_info',
                               key='fake-56789')
 
     def test_vendor_passthru_validate_key_notmatch(self):
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.validate,
+                              task.driver.vendor.validate,
                               task, method='pass_deploy_info',
                               address='123456', iqn='aaa-bbb',
                               key='fake-12345')
@@ -814,9 +814,9 @@ class PXEDriverTestCase(db_base.DbTestCase):
                 fake_deploy))
 
         with task_manager.acquire(self.context, self.node.uuid) as task:
-            task.resources[0].driver.vendor.vendor_passthru(task,
-                    method='pass_deploy_info', address='123456', iqn='aaa-bbb',
-                    key='fake-56789')
+            task.driver.vendor.vendor_passthru(
+                    task, method='pass_deploy_info', address='123456',
+                    iqn='aaa-bbb', key='fake-56789')
         self.node.refresh(self.context)
         self.assertEqual(states.ACTIVE, self.node.provision_state)
         self.assertEqual(states.POWER_ON, self.node.power_state)
@@ -839,10 +839,10 @@ class PXEDriverTestCase(db_base.DbTestCase):
                 'ironic.drivers.modules.deploy_utils.deploy',
                 fake_deploy))
 
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
-            task.resources[0].driver.vendor.vendor_passthru(task,
-                    method='pass_deploy_info', address='123456', iqn='aaa-bbb',
-                    key='fake-56789')
+        with task_manager.acquire(self.context, self.node.uuid) as task:
+            task.driver.vendor.vendor_passthru(
+                    task, method='pass_deploy_info', address='123456',
+                    iqn='aaa-bbb', key='fake-56789')
         self.node.refresh(self.context)
         self.assertEqual(states.DEPLOYFAIL, self.node.provision_state)
         self.assertEqual(states.POWER_OFF, self.node.power_state)
@@ -865,10 +865,11 @@ class PXEDriverTestCase(db_base.DbTestCase):
                 'ironic.drivers.modules.deploy_utils.deploy',
                 fake_deploy))
 
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
-            task.resources[0].driver.vendor.vendor_passthru(task,
-                    method='pass_deploy_info', address='123456', iqn='aaa-bbb',
-                    key='fake-56789', error='test ramdisk error')
+        with task_manager.acquire(self.context, self.node.uuid) as task:
+            task.driver.vendor.vendor_passthru(
+                    task, method='pass_deploy_info', address='123456',
+                    iqn='aaa-bbb', key='fake-56789',
+                    error='test ramdisk error')
         self.node.refresh(self.context)
         self.assertEqual(states.DEPLOYFAIL, self.node.provision_state)
         self.assertEqual(states.POWER_OFF, self.node.power_state)
@@ -882,16 +883,17 @@ class PXEDriverTestCase(db_base.DbTestCase):
         self.node.provision_state = 'FAKE'
         self.node.save()
 
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
-            task.resources[0].driver.vendor.vendor_passthru(task,
-                    method='pass_deploy_info', address='123456', iqn='aaa-bbb',
-                    key='fake-56789', error='test ramdisk error')
+        with task_manager.acquire(self.context, self.node.uuid) as task:
+            task.driver.vendor.vendor_passthru(
+                    task, method='pass_deploy_info', address='123456',
+                    iqn='aaa-bbb', key='fake-56789',
+                    error='test ramdisk error')
         self.node.refresh(self.context)
         self.assertEqual('FAKE', self.node.provision_state)
         self.assertEqual(states.POWER_ON, self.node.power_state)
 
     def test_lock_elevated(self):
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
+        with task_manager.acquire(self.context, self.node.uuid) as task:
             with mock.patch.object(task.driver.vendor, '_continue_deploy') \
                     as _continue_deploy_mock:
                 task.driver.vendor.vendor_passthru(task,
@@ -969,9 +971,9 @@ class PXEDriverTestCase(db_base.DbTestCase):
         token_path = self._create_token_file()
         self.config(image_cache_size=0, group='pxe')
 
-        with task_manager.acquire(self.context, [self.node.uuid],
+        with task_manager.acquire(self.context, self.node.uuid,
                                   shared=True) as task:
-            task.resources[0].driver.deploy.clean_up(task)
+            task.driver.deploy.clean_up(task)
             get_tftp_image_info_mock.called_once_with(task.node)
         assert_false_path = [config_path, deploy_kernel_path, image_path,
                              pxe_mac_path, image_dir, instance_dir,
diff --git a/ironic/tests/drivers/test_seamicro.py b/ironic/tests/drivers/test_seamicro.py
index cc47bbaa8..400add9a4 100644
--- a/ironic/tests/drivers/test_seamicro.py
+++ b/ironic/tests/drivers/test_seamicro.py
@@ -280,20 +280,19 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
     @mock.patch.object(seamicro, '_parse_driver_info')
     def test_power_interface_validate_good(self, parse_drv_info_mock):
-        with task_manager.acquire(self.context, [self.node['uuid']],
+        with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=True) as task:
-            task.resources[0].driver.power.validate(
-                        task, self.node)
+            task.driver.power.validate(task, self.node)
         self.assertEqual(1, parse_drv_info_mock.call_count)
 
     @mock.patch.object(seamicro, '_parse_driver_info')
     def test_power_interface_validate_fails(self, parse_drv_info_mock):
         side_effect = exception.InvalidParameterValue("Bad input")
         parse_drv_info_mock.side_effect = side_effect
-        with task_manager.acquire(self.context, [self.node['uuid']],
+        with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.power.validate,
+                              task.driver.power.validate,
                               task, self.node)
         self.assertEqual(1, parse_drv_info_mock.call_count)
 
@@ -303,9 +302,9 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
         mock_reboot.return_value = states.POWER_ON
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
-            task.resources[0].driver.power.reboot(task)
+            task.driver.power.reboot(task)
 
             mock_reboot.assert_called_once_with(task.node)
 
@@ -314,10 +313,10 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         self.get_server_mock = self.get_server_patcher.start()
         self.get_server_mock.return_value = self.Server()
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.IronicException,
-                              task.resources[0].driver.power.set_power_state,
+                              task.driver.power.set_power_state,
                               task, "BAD_PSTATE")
         self.get_server_patcher.stop()
 
@@ -327,10 +326,9 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
         mock_power_on.return_value = states.POWER_ON
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
-            task.resources[0].driver.power.set_power_state(task,
-                                                           states.POWER_ON)
+            task.driver.power.set_power_state(task, states.POWER_ON)
 
             mock_power_on.assert_called_once_with(task.node)
 
@@ -340,11 +338,10 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
         mock_power_on.return_value = states.POWER_OFF
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.PowerStateFailure,
-                              task.resources[0]
-                              .driver.power.set_power_state,
+                              task.driver.power.set_power_state,
                               task, states.POWER_ON)
 
             mock_power_on.assert_called_once_with(task.node)
@@ -355,10 +352,9 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
         mock_power_off.return_value = states.POWER_OFF
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
-            task.resources[0].driver.power.\
-                set_power_state(task, states.POWER_OFF)
+            task.driver.power.set_power_state(task, states.POWER_OFF)
 
             mock_power_off.assert_called_once_with(task.node)
 
@@ -368,27 +364,25 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
         mock_power_off.return_value = states.POWER_ON
 
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.PowerStateFailure,
-                              task.resources[0]
-                              .driver.power.set_power_state,
+                              task.driver.power.set_power_state,
                               task, states.POWER_OFF)
 
             mock_power_off.assert_called_once_with(task.node)
 
     def test_vendor_passthru_validate_good(self):
-        with task_manager.acquire(self.context, [self.node['uuid']],
+        with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=True) as task:
             for method in seamicro.VENDOR_PASSTHRU_METHODS:
-                task.resources[0].driver.vendor.validate(
-                        task, **{'method': method})
+                task.driver.vendor.validate(task, **{'method': method})
 
     def test_vendor_passthru_validate_fail(self):
-        with task_manager.acquire(self.context, [self.node['uuid']],
+        with task_manager.acquire(self.context, self.node['uuid'],
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.validate,
+                              task.driver.vendor.validate,
                               task, **{'method': 'invalid_method'})
 
     @mock.patch.object(seamicro, '_get_server')
@@ -396,20 +390,19 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         info = seamicro._parse_driver_info(self.node)
         vlan_id = "12"
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'vlan_id': vlan_id, 'method': 'set_node_vlan_id'}
-            task.resources[0].driver.vendor.\
-                vendor_passthru(task, **kwargs)
+            task.driver.vendor.vendor_passthru(task, **kwargs)
         mock_get_server.assert_called_once_with(info)
 
     def test_set_node_vlan_id_no_input(self):
         info = seamicro._parse_driver_info(self.node)
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task,
+                              task.driver.vendor.vendor_passthru,
+                              task,
                               **{'method': 'set_node_vlan_id'})
 
     @mock.patch.object(seamicro, '_get_server')
@@ -422,12 +415,13 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         server = self.Server(active="true")
         server.set_untagged_vlan = fake_set_untagged_vlan
         mock_get_server.return_value = server
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'vlan_id': vlan_id, 'method': 'set_node_vlan_id'}
             self.assertRaises(exception.IronicException,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task, **kwargs)
+                              task.driver.vendor.vendor_passthru,
+                              task,
+                              **kwargs)
 
         mock_get_server.assert_called_once_with(info)
 
@@ -439,11 +433,10 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         volume_id = '0/ironic-p6-1/vol1'
         mock_validate_volume.return_value = True
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'volume_id': volume_id, 'method': 'attach_volume'}
-            task.resources[0].driver.vendor.\
-                vendor_passthru(task, **kwargs)
+            task.driver.vendor.vendor_passthru(task, **kwargs)
         mock_get_server.assert_called_once_with(info)
 
     @mock.patch.object(seamicro, '_get_server')
@@ -455,12 +448,13 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         volume_id = '0/p6-1/vol1'
         mock_get_volume.return_value = self.Volume(volume_id)
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'volume_id': volume_id, 'method': 'attach_volume'}
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task, **kwargs)
+                              task.driver.vendor.vendor_passthru,
+                              task,
+                              **kwargs)
 
     @mock.patch.object(seamicro, '_get_server')
     @mock.patch.object(seamicro, '_validate_volume')
@@ -475,12 +469,13 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         server = self.Server(active="true")
         server.attach_volume = fake_attach_volume
         mock_get_server.return_value = server
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'volume_id': volume_id, 'method': 'attach_volume'}
             self.assertRaises(exception.IronicException,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task, **kwargs)
+                              task.driver.vendor.vendor_passthru,
+                              task,
+                              **kwargs)
 
         mock_get_server.assert_called_once_with(info)
 
@@ -496,21 +491,19 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         mock_create_volume.return_value = volume_id
         mock_validate_volume.return_value = True
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'volume_size': volume_size, 'method': "attach_volume"}
-            task.resources[0].driver.vendor.\
-                vendor_passthru(task, **kwargs)
+            task.driver.vendor.vendor_passthru(task, **kwargs)
         mock_get_server.assert_called_once_with(info)
         mock_create_volume.assert_called_once_with(info, volume_size)
 
     def test_attach_volume_with_no_input_fail(self):
         info = seamicro._parse_driver_info(self.node)
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task,
+                              task.driver.vendor.vendor_passthru, task,
                               **{'method': 'attach_volume'})
 
     @mock.patch.object(seamicro, '_get_server')
@@ -518,20 +511,18 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         info = seamicro._parse_driver_info(self.node)
         boot_device = "disk"
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'device': boot_device, 'method': 'set_boot_device'}
-            task.resources[0].driver.vendor.\
-                vendor_passthru(task, **kwargs)
+            task.driver.vendor.vendor_passthru(task, **kwargs)
         mock_get_server.assert_called_once_with(info)
 
     def test_set_boot_device_no_input(self):
         info = seamicro._parse_driver_info(self.node)
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task,
+                              task.driver.vendor.vendor_passthru, task,
                               **{'method': 'set_boot_device'})
 
     @mock.patch.object(seamicro, '_get_server')
@@ -539,12 +530,13 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         info = seamicro._parse_driver_info(self.node)
         boot_device = "invalid_device"
         mock_get_server.return_value = self.Server(active="true")
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'device': boot_device, 'method': 'set_boot_device'}
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task, **kwargs)
+                              task.driver.vendor.vendor_passthru,
+                              task,
+                              **kwargs)
 
     @mock.patch.object(seamicro, '_get_server')
     def test_set_boot_device_fail(self, mock_get_server):
@@ -556,11 +548,12 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
         server = self.Server(active="true")
         server.set_boot_order = fake_set_boot_order
         mock_get_server.return_value = server
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             kwargs = {'device': boot_device, 'method': 'set_boot_device'}
             self.assertRaises(exception.IronicException,
-                              task.resources[0].driver.vendor.
-                              vendor_passthru, task, **kwargs)
+                              task.driver.vendor.vendor_passthru,
+                              task,
+                              **kwargs)
 
         mock_get_server.assert_called_once_with(info)
diff --git a/ironic/tests/drivers/test_ssh.py b/ironic/tests/drivers/test_ssh.py
index 1a6593729..2e2e66ec9 100644
--- a/ironic/tests/drivers/test_ssh.py
+++ b/ironic/tests/drivers/test_ssh.py
@@ -573,10 +573,10 @@ class SSHDriverTestCase(db_base.DbTestCase):
         info = ssh._parse_driver_info(self.node)
 
         ssh_connect_mock.side_effect = exception.SSHConnectFailed(host='fake')
-        with task_manager.acquire(self.context, [info['uuid']],
+        with task_manager.acquire(self.context, info['uuid'],
                                   shared=False) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.power.validate,
+                              task.driver.power.validate,
                               task, self.node)
             driver_info = ssh._parse_driver_info(self.node)
             ssh_connect_mock.assert_called_once_with(driver_info)
@@ -588,10 +588,10 @@ class SSHDriverTestCase(db_base.DbTestCase):
                 uuid='aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee',
                 driver='fake_ssh',
                 driver_info=db_utils.get_test_ssh_info())
-        with task_manager.acquire(self.context, [new_node.uuid],
+        with task_manager.acquire(self.context, new_node.uuid,
                                   shared=True) as task:
             self.assertRaises(exception.InvalidParameterValue,
-                              task.resources[0].driver.power.validate,
+                              task.driver.power.validate,
                               task, new_node)
 
     @mock.patch.object(driver_utils, 'get_node_mac_addresses')
@@ -612,9 +612,9 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
-                task.resources[0].driver.power.reboot(task)
+                task.driver.power.reboot(task)
 
                 parse_drv_info_mock.assert_called_once_with(task.node)
                 get_mac_addr_mock.assert_called_once_with(mock.ANY)
@@ -642,11 +642,10 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
                 self.assertRaises(exception.PowerStateFailure,
-                                  task.resources[0].driver.power.reboot,
-                                  task)
+                                  task.driver.power.reboot, task)
                 parse_drv_info_mock.assert_called_once_with(task.node)
                 get_mac_addr_mock.assert_called_once_with(mock.ANY)
                 get_conn_mock.assert_called_once_with(task.node)
@@ -666,11 +665,11 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
                 self.assertRaises(
                     exception.InvalidParameterValue,
-                    task.resources[0].driver.power.set_power_state,
+                    task.driver.power.set_power_state,
                     task,
                     "BAD_PSTATE")
 
@@ -691,10 +690,9 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
-                task.resources[0].driver.power.set_power_state(task,
-                                                               states.POWER_ON)
+                task.driver.power.set_power_state(task, states.POWER_ON)
 
                 parse_drv_info_mock.assert_called_once_with(task.node)
                 get_mac_addr_mock.assert_called_once_with(mock.ANY)
@@ -714,11 +712,11 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
                 self.assertRaises(
                     exception.PowerStateFailure,
-                    task.resources[0].driver.power.set_power_state,
+                    task.driver.power.set_power_state,
                     task,
                     states.POWER_ON)
 
@@ -740,10 +738,9 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
-                task.resources[0].driver.power.set_power_state(
-                                                        task, states.POWER_OFF)
+                task.driver.power.set_power_state(task, states.POWER_OFF)
 
                 parse_drv_info_mock.assert_called_once_with(task.node)
                 get_mac_addr_mock.assert_called_once_with(mock.ANY)
@@ -763,11 +760,11 @@ class SSHDriverTestCase(db_base.DbTestCase):
         with mock.patch.object(ssh,
                                '_parse_driver_info') as parse_drv_info_mock:
             parse_drv_info_mock.return_value = info
-            with task_manager.acquire(self.context, [info['uuid']],
+            with task_manager.acquire(self.context, info['uuid'],
                                       shared=False) as task:
                 self.assertRaises(
                     exception.PowerStateFailure,
-                    task.resources[0].driver.power.set_power_state,
+                    task.driver.power.set_power_state,
                     task,
                     states.POWER_OFF)
 
diff --git a/ironic/tests/drivers/test_utils.py b/ironic/tests/drivers/test_utils.py
index c4308e068..799d3ca09 100644
--- a/ironic/tests/drivers/test_utils.py
+++ b/ironic/tests/drivers/test_utils.py
@@ -121,6 +121,6 @@ class UtilsTestCase(base.TestCase):
                     address='dd:ee:ff',
                     uuid='4fc26c0b-03f2-4d2e-ae87-c02d7f33c234',
                     node_id=self.node.id)))
-        with task_manager.acquire(self.context, [self.node.uuid]) as task:
+        with task_manager.acquire(self.context, self.node.uuid) as task:
             node_macs = driver_utils.get_node_mac_addresses(task)
         self.assertEqual(sorted([p.address for p in ports]), sorted(node_macs))