Introduce VirtAPI to nova/virt

This patch introduces a VirtAPI class which will house
callbacks provided by the manager to the virt drivers, allowing
things such as direct database accesses to be pulled out of
the virt drivers and delegated to another service.

As a first step, this introduces an instance_update() method
and makes all the virt drivers use it instead of direct calls
to db.instance_update.*().

Change-Id: I2e40831f5cfb20a03b304097d84d592aab035ef1

19 files changed, 231 insertions, 177 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index dac9b58a0..73260421e 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -73,6 +73,7 @@ from nova import quota
 from nova.scheduler import rpcapi as scheduler_rpcapi
 from nova import utils
 from nova.virt import driver
+from nova.virt import virtapi
 from nova import volume
 
 
@@ -209,6 +210,17 @@ def _get_image_meta(context, image_ref):
     return image_service.show(context, image_id)
 
 
+class ComputeVirtAPI(virtapi.VirtAPI):
+    def __init__(self, compute):
+        super(ComputeVirtAPI, self).__init__()
+        self._compute = compute
+
+    def instance_update(self, context, instance_uuid, updates):
+        return self._compute.db.instance_update_and_get_original(context,
+                                                                 instance_uuid,
+                                                                 updates)
+
+
 class ComputeManager(manager.SchedulerDependentManager):
     """Manages the running instances from creation to destruction."""
 
@@ -225,10 +237,13 @@ class ComputeManager(manager.SchedulerDependentManager):
             LOG.error(_("Compute driver option required, but not specified"))
             sys.exit(1)
 
+        self.virtapi = ComputeVirtAPI(self)
+
         LOG.info(_("Loading compute driver '%s'") % compute_driver)
         try:
             self.driver = utils.check_isinstance(
-                    importutils.import_object_ns('nova.virt', compute_driver),
+                    importutils.import_object_ns('nova.virt', compute_driver,
+                                                 self.virtapi),
                     driver.ComputeDriver)
         except ImportError as e:
             LOG.error(_("Unable to load the virtualization driver: %s") % (e))
diff --git a/nova/tests/baremetal/test_proxy_bare_metal.py b/nova/tests/baremetal/test_proxy_bare_metal.py
index 4fe6722c3..e9184ee5d 100644
--- a/nova/tests/baremetal/test_proxy_bare_metal.py
+++ b/nova/tests/baremetal/test_proxy_bare_metal.py
@@ -257,7 +257,7 @@ class BareMetalTestCase(test.TestCase):
         self.mox.ReplayAll()
 
         # Code under test
-        conn = driver.BareMetalDriver(True)
+        conn = driver.BareMetalDriver(None, True)
         # TODO(mikalstill): this is not a very good fake instance
         info = conn.get_info({'name': 'instance-00000001'})
 
diff --git a/nova/tests/compute/test_resource_tracker.py b/nova/tests/compute/test_resource_tracker.py
index 6276c47ac..dfeebf0d0 100644
--- a/nova/tests/compute/test_resource_tracker.py
+++ b/nova/tests/compute/test_resource_tracker.py
@@ -42,7 +42,7 @@ class UnsupportedVirtDriver(driver.ComputeDriver):
 
 class FakeVirtDriver(driver.ComputeDriver):
 
-    def __init__(self):
+    def __init__(self, virtapi):
         self.memory_mb = 5
         self.local_gb = 6
         self.vcpus = 1
@@ -148,9 +148,9 @@ class BaseTestCase(test.TestCase):
         host = "fakehost"
 
         if unsupported:
-            driver = UnsupportedVirtDriver()
+            driver = UnsupportedVirtDriver(None)
         else:
-            driver = FakeVirtDriver()
+            driver = FakeVirtDriver(None)
 
         tracker = resource_tracker.ResourceTracker(host, driver)
         return tracker
@@ -293,12 +293,12 @@ class ResourceTestCase(BaseTestCase):
         self.assertEqual(1, self.tracker.compute_node['current_workload'])
 
     def testFreeRamResourceValue(self):
-        driver = FakeVirtDriver()
+        driver = FakeVirtDriver(None)
         mem_free = driver.memory_mb - driver.memory_mb_used
         self.assertEqual(mem_free, self.tracker.compute_node['free_ram_mb'])
 
     def testFreeDiskResourceValue(self):
-        driver = FakeVirtDriver()
+        driver = FakeVirtDriver(None)
         mem_free = driver.local_gb - driver.local_gb_used
         self.assertEqual(mem_free, self.tracker.compute_node['free_disk_gb'])
 
diff --git a/nova/tests/test_hypervapi.py b/nova/tests/test_hypervapi.py
index e3f9fde4c..6d2396350 100644
--- a/nova/tests/test_hypervapi.py
+++ b/nova/tests/test_hypervapi.py
@@ -66,7 +66,7 @@ class HyperVAPITestCase(basetestcase.BaseTestCase):
                         vswitch_name='external')
 
         self._hypervutils = hypervutils.HyperVUtils()
-        self._conn = driver_hyperv.HyperVDriver()
+        self._conn = driver_hyperv.HyperVDriver(None)
 
     def _setup_stubs(self):
         db_fakes.stub_out_db_instance_api(self.stubs)
diff --git a/nova/tests/test_libvirt.py b/nova/tests/test_libvirt.py
index 5a158c4b2..ea35ff29e 100644
--- a/nova/tests/test_libvirt.py
+++ b/nova/tests/test_libvirt.py
@@ -48,6 +48,7 @@ import nova.tests.image.fake
 from nova import utils
 from nova.virt.disk import api as disk
 from nova.virt import driver
+from nova.virt import fake
 from nova.virt import firewall as base_firewall
 from nova.virt import images
 from nova.virt.libvirt import config
@@ -147,7 +148,7 @@ class LibvirtVolumeTestCase(test.TestCase):
             def get_all_block_devices(self):
                 return []
 
-        self.fake_conn = FakeLibvirtDriver()
+        self.fake_conn = FakeLibvirtDriver(fake.FakeVirtAPI())
         self.connr = {
             'ip': '127.0.0.1',
             'initiator': 'fake_initiator',
@@ -619,7 +620,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.flags(my_ip=ip)
         self.flags(host=host)
 
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         expected = {
             'ip': ip,
             'initiator': initiator,
@@ -632,7 +633,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.assertDictMatch(expected, result)
 
     def test_get_guest_config(self):
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         cfg = conn.get_guest_config(instance_ref,
@@ -676,7 +677,7 @@ class LibvirtConnTestCase(test.TestCase):
                           "catchup")
 
     def test_get_guest_config_with_two_nics(self):
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         cfg = conn.get_guest_config(instance_ref,
@@ -708,7 +709,7 @@ class LibvirtConnTestCase(test.TestCase):
 
     def test_get_guest_config_with_root_device_name(self):
         self.flags(libvirt_type='uml')
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         cfg = conn.get_guest_config(instance_ref, [], None, None,
@@ -728,7 +729,7 @@ class LibvirtConnTestCase(test.TestCase):
                           config.LibvirtConfigGuestConsole)
 
     def test_get_guest_config_with_block_device(self):
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
         instance_ref = db.instance_create(self.context, self.test_instance)
         conn_info = {'driver_volume_type': 'fake'}
@@ -746,7 +747,7 @@ class LibvirtConnTestCase(test.TestCase):
 
     def test_get_guest_cpu_config_none(self):
         self.flags(libvirt_cpu_mode="none")
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         conf = conn.get_guest_config(instance_ref,
@@ -764,7 +765,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt.virConnect,
                        "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         conf = conn.get_guest_config(instance_ref,
@@ -779,7 +780,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.flags(libvirt_type="uml",
                    libvirt_cpu_mode=None)
 
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         conf = conn.get_guest_config(instance_ref,
@@ -791,7 +792,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.flags(libvirt_type="lxc",
                    libvirt_cpu_mode=None)
 
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         conf = conn.get_guest_config(instance_ref,
@@ -806,7 +807,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt.virConnect,
                        "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="host-passthrough")
@@ -825,7 +826,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt.virConnect,
                        "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="host-model")
@@ -844,7 +845,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt.virConnect,
                        "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="custom")
@@ -863,7 +864,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.stubs.Set(libvirt.virConnect, "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="host-passthrough")
@@ -894,7 +895,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt_driver.LibvirtDriver,
                        "get_host_capabilities",
                        get_host_capabilities_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="host-model")
@@ -914,7 +915,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.stubs.Set(libvirt.virConnect,
                        "getLibVersion",
                        get_lib_version_stub)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, self.test_instance)
 
         self.flags(libvirt_cpu_mode="custom")
@@ -1038,7 +1039,7 @@ class LibvirtConnTestCase(test.TestCase):
         libvirt_driver.LibvirtDriver._conn.listDomainsID = lambda: [0, 1]
 
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         instances = conn.list_instances()
         # Only one should be listed, since domain with ID 0 must be skiped
         self.assertEquals(len(instances), 1)
@@ -1054,7 +1055,7 @@ class LibvirtConnTestCase(test.TestCase):
         libvirt_driver.LibvirtDriver._conn.listDomainsID = lambda: [0, 1]
 
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         instances = conn.list_instances()
         # None should be listed, since we fake deleted the last one
         self.assertEquals(len(instances), 0)
@@ -1107,7 +1108,7 @@ class LibvirtConnTestCase(test.TestCase):
         libvirt_driver.LibvirtDriver._conn.lookupByID = fake_lookup
 
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         devices = conn.get_all_block_devices()
         self.assertEqual(devices, ['/path/to/dev/1', '/path/to/dev/3'])
 
@@ -1168,7 +1169,7 @@ class LibvirtConnTestCase(test.TestCase):
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         devices = conn.get_disks(conn.list_instances()[0])
         self.assertEqual(devices, ['vda', 'vdb'])
 
@@ -1201,7 +1202,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1240,7 +1241,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1279,7 +1280,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1319,7 +1320,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1354,7 +1355,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1390,7 +1391,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1428,7 +1429,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1466,7 +1467,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1499,7 +1500,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.mox.ReplayAll()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         conn.snapshot(self.context, instance_ref, recv_meta['id'])
 
         snapshot = image_service.show(context, recv_meta['id'])
@@ -1545,7 +1546,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.create_fake_libvirt_mock()
         libvirt_driver.LibvirtDriver._conn.lookupByName = self.fake_lookup
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.assertRaises(exception.VolumeDriverNotFound,
                           conn.attach_volume,
                           {"driver_volume_type": "badtype"},
@@ -1555,7 +1556,7 @@ class LibvirtConnTestCase(test.TestCase):
     def test_multi_nic(self):
         instance_data = dict(self.test_instance)
         network_info = _fake_network_info(self.stubs, 2)
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         instance_ref = db.instance_create(self.context, instance_data)
         xml = conn.to_xml(instance_ref, network_info, None, False)
         tree = etree.fromstring(xml)
@@ -1572,7 +1573,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(user_context, instance)
 
         self.flags(libvirt_type='lxc')
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
         self.assertEquals(conn.uri, 'lxc:///')
 
@@ -1615,7 +1616,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         for (libvirt_type, checks) in type_disk_map.iteritems():
             self.flags(libvirt_type=libvirt_type)
-            conn = libvirt_driver.LibvirtDriver(True)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
             network_info = _fake_network_info(self.stubs, 1)
             xml = conn.to_xml(instance_ref, network_info)
@@ -1651,9 +1652,8 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(user_context, self.test_instance)
         network_info = _fake_network_info(self.stubs, 1)
 
-        xml = libvirt_driver.LibvirtDriver(True).to_xml(instance_ref,
-                                                        network_info,
-                                                        image_meta)
+        xml = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True).to_xml(
+            instance_ref, network_info, image_meta)
         tree = etree.fromstring(xml)
         disks = tree.findall('./devices/disk/driver')
         for disk in disks:
@@ -1663,9 +1663,8 @@ class LibvirtConnTestCase(test.TestCase):
 
         # The O_DIRECT availability is cached on first use in
         # LibvirtDriver, hence we re-create it here
-        xml = libvirt_driver.LibvirtDriver(True).to_xml(instance_ref,
-                                                        network_info,
-                                                        image_meta)
+        xml = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True).to_xml(
+            instance_ref, network_info, image_meta)
         tree = etree.fromstring(xml)
         disks = tree.findall('./devices/disk/driver')
         for disk in disks:
@@ -1677,7 +1676,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(user_context, self.test_instance)
         network_info = _fake_network_info(self.stubs, 1)
 
-        xml = libvirt_driver.LibvirtDriver(True).to_xml(
+        xml = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True).to_xml(
             instance_ref,
             network_info,
             image_meta,
@@ -1704,9 +1703,8 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(user_context, self.test_instance)
         network_info = _fake_network_info(self.stubs, 1)
 
-        xml = libvirt_driver.LibvirtDriver(True).to_xml(instance_ref,
-                                                        network_info,
-                                                        image_meta)
+        xml = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True).to_xml(
+            instance_ref, network_info, image_meta)
         tree = etree.fromstring(xml)
         self.assertEqual(tree.find('./uuid').text,
                          instance_ref['uuid'])
@@ -1818,7 +1816,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         for (libvirt_type, (expected_uri, checks)) in type_uri_map.iteritems():
             self.flags(libvirt_type=libvirt_type)
-            conn = libvirt_driver.LibvirtDriver(True)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
             self.assertEquals(conn.uri, expected_uri)
 
@@ -1847,7 +1845,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.flags(libvirt_uri=testuri)
         for (libvirt_type, (expected_uri, checks)) in type_uri_map.iteritems():
             self.flags(libvirt_type=libvirt_type)
-            conn = libvirt_driver.LibvirtDriver(True)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
             self.assertEquals(conn.uri, testuri)
         db.instance_destroy(user_context, instance_ref['uuid'])
 
@@ -1879,7 +1877,7 @@ class LibvirtConnTestCase(test.TestCase):
         # Start test
         self.mox.ReplayAll()
         try:
-            conn = libvirt_driver.LibvirtDriver(False)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
             self.stubs.Set(conn.firewall_driver,
                            'setup_basic_filtering',
                            fake_none)
@@ -1907,7 +1905,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(self.context, self.test_instance)
         dest = "fake_host_2"
         src = instance_ref['host']
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         compute_info = {'disk_available_least': 400,
                         'cpu_info': 'asdf',
                         }
@@ -1935,7 +1933,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(self.context, self.test_instance)
         dest = "fake_host_2"
         src = instance_ref['host']
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         compute_info = {'cpu_info': 'asdf'}
         filename = "file"
 
@@ -1961,7 +1959,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(self.context, self.test_instance)
         dest = "fake_host_2"
         src = instance_ref['host']
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         compute_info = {'cpu_info': 'asdf'}
 
         self.mox.StubOutWithMock(conn, '_compare_cpu')
@@ -1980,7 +1978,7 @@ class LibvirtConnTestCase(test.TestCase):
                            "block_migration": True,
                            "disk_over_commit": False,
                            "disk_available_mb": 1024}
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         self.mox.StubOutWithMock(conn, '_cleanup_shared_storage_test_file')
         conn._cleanup_shared_storage_test_file("file")
@@ -1995,7 +1993,7 @@ class LibvirtConnTestCase(test.TestCase):
                            "block_migration": True,
                            "disk_over_commit": False,
                            "disk_available_mb": 1024}
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
         conn._check_shared_storage_test_file("file").AndReturn(False)
@@ -2015,7 +2013,7 @@ class LibvirtConnTestCase(test.TestCase):
                            "block_migration": True,
                            "disk_over_commit": False,
                            'disk_available_mb': 1024}
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
         conn._check_shared_storage_test_file("file").AndReturn(True)
@@ -2031,7 +2029,7 @@ class LibvirtConnTestCase(test.TestCase):
                            "block_migration": False,
                            "disk_over_commit": False,
                            'disk_available_mb': 1024}
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
         conn._check_shared_storage_test_file("file").AndReturn(False)
@@ -2045,7 +2043,7 @@ class LibvirtConnTestCase(test.TestCase):
         instance_ref = db.instance_create(self.context, self.test_instance)
         dest = "fake_host_2"
         src = instance_ref['host']
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         self.mox.StubOutWithMock(conn, "_check_shared_storage_test_file")
         conn._check_shared_storage_test_file("file").AndReturn(False)
@@ -2100,7 +2098,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         #start test
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.assertRaises(libvirt.libvirtError,
                       conn._live_migration,
                       self.context, instance_ref, 'dest', False,
@@ -2120,7 +2118,7 @@ class LibvirtConnTestCase(test.TestCase):
         vol = {'block_device_mapping': [
                   {'connection_info': 'dummy', 'mount_device': '/dev/sda'},
                   {'connection_info': 'dummy', 'mount_device': '/dev/sdb'}]}
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         class FakeNetworkInfo():
             def fixed_ips(self):
@@ -2174,7 +2172,7 @@ class LibvirtConnTestCase(test.TestCase):
                                      user_id=None).AndReturn(None)
             self.mox.ReplayAll()
 
-            conn = libvirt_driver.LibvirtDriver(False)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
             conn.pre_block_migration(self.context, instance_ref,
                                      dummyjson)
 
@@ -2227,7 +2225,7 @@ class LibvirtConnTestCase(test.TestCase):
                       '/test/disk.local').AndReturn((ret, ''))
 
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         info = conn.get_instance_disk_info(instance_ref.name)
         info = jsonutils.loads(info)
         self.assertEquals(info[0]['type'], 'raw')
@@ -2284,7 +2282,7 @@ class LibvirtConnTestCase(test.TestCase):
 
         # Start test
         self.mox.ReplayAll()
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn.firewall_driver,
                        'setup_basic_filtering',
                        fake_none)
@@ -2343,7 +2341,7 @@ class LibvirtConnTestCase(test.TestCase):
             libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup
             libvirt_driver.libvirt_utils = fake_libvirt_utils
 
-            conn = libvirt_driver.LibvirtDriver(False)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
             output = conn.get_console_output(instance)
             self.assertEquals("foo", output)
 
@@ -2388,12 +2386,12 @@ class LibvirtConnTestCase(test.TestCase):
             libvirt_driver.LibvirtDriver._flush_libvirt_console = _fake_flush
             libvirt_driver.libvirt_utils = fake_libvirt_utils
 
-            conn = libvirt_driver.LibvirtDriver(False)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
             output = conn.get_console_output(instance)
             self.assertEquals("foo", output)
 
     def test_get_host_ip_addr(self):
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         ip = conn.get_host_ip_addr()
         self.assertEquals(ip, FLAGS.my_ip)
 
@@ -2402,7 +2400,7 @@ class LibvirtConnTestCase(test.TestCase):
                 (libvirt.VIR_ERR_SYSTEM_ERROR, libvirt.VIR_FROM_REMOTE),
                 (libvirt.VIR_ERR_SYSTEM_ERROR, libvirt.VIR_FROM_RPC)):
 
-            conn = libvirt_driver.LibvirtDriver(False)
+            conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
             self.mox.StubOutWithMock(conn, "_wrapped_conn")
             self.mox.StubOutWithMock(conn._wrapped_conn, "getCapabilities")
@@ -2422,7 +2420,7 @@ class LibvirtConnTestCase(test.TestCase):
             self.mox.UnsetStubs()
 
     def test_volume_in_mapping(self):
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         swap = {'device_name': '/dev/sdb',
                 'swap_size': 1}
         ephemerals = [{'num': 0,
@@ -2461,7 +2459,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_lookup_by_name(instance_name):
             raise exception.InstanceNotFound()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
 
         instance = db.instance_create(self.context, self.test_instance)
@@ -2480,7 +2478,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_get_info(instance_name):
             return {'state': power_state.SHUTDOWN}
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
         self.stubs.Set(conn, 'get_info', fake_get_info)
         instance = {"name": "instancename", "id": "instanceid",
@@ -2501,7 +2499,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_get_info(instance_name):
             return {'state': power_state.SHUTDOWN}
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
         self.stubs.Set(conn, 'get_info', fake_get_info)
         instance = {"name": "instancename", "id": "instanceid",
@@ -2524,7 +2522,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_get_info(instance_name):
             return {'state': power_state.SHUTDOWN}
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
         self.stubs.Set(conn, 'get_info', fake_get_info)
         instance = {"name": "instancename", "id": "instanceid",
@@ -2546,7 +2544,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_get_info(instance_name):
             return {'state': power_state.SHUTDOWN}
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
         self.stubs.Set(conn, 'get_info', fake_get_info)
         instance = {"name": "instancename", "id": "instanceid",
@@ -2564,7 +2562,7 @@ class LibvirtConnTestCase(test.TestCase):
         def fake_get_info(instance_name):
             raise exception.InstanceNotFound()
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         self.stubs.Set(conn, '_lookup_by_name', fake_lookup_by_name)
         self.stubs.Set(conn, 'get_info', fake_get_info)
         instance = {"name": "instancename", "id": "instanceid",
@@ -2574,7 +2572,7 @@ class LibvirtConnTestCase(test.TestCase):
 
     def test_available_least_handles_missing(self):
         """Ensure destroy calls managedSaveRemove for saved instance"""
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
 
         def list_instances():
             return ['fake']
@@ -2589,7 +2587,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.assertEqual(result, space / 1024 ** 3)
 
     def test_cpu_info(self):
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
         def get_host_capabilities_stub(self):
             cpu = config.LibvirtConfigCPU()
@@ -2681,7 +2679,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         actual = conn.get_diagnostics({"name": "testvirt"})
         expect = {'vda_read': 688640L,
                   'vda_read_req': 169L,
@@ -2761,7 +2759,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         actual = conn.get_diagnostics({"name": "testvirt"})
         expect = {'cpu0_time': 15340000000L,
                   'cpu1_time': 1640000000L,
@@ -2835,7 +2833,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         actual = conn.get_diagnostics({"name": "testvirt"})
         expect = {'cpu0_time': 15340000000L,
                   'cpu1_time': 1640000000L,
@@ -2911,7 +2909,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         actual = conn.get_diagnostics({"name": "testvirt"})
         expect = {'cpu0_time': 15340000000L,
                   'cpu1_time': 1640000000L,
@@ -2993,7 +2991,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(libvirt_driver.LibvirtDriver, '_conn')
         libvirt_driver.LibvirtDriver._conn.lookupByName = fake_lookup_name
 
-        conn = libvirt_driver.LibvirtDriver(False)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
         actual = conn.get_diagnostics({"name": "testvirt"})
         expect = {'cpu0_time': 15340000000L,
                   'cpu1_time': 1640000000L,
@@ -3024,7 +3022,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.assertEqual(actual, expect)
 
     def test_get_instance_capabilities(self):
-        conn = libvirt_driver.LibvirtDriver(True)
+        conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
         def get_host_capabilities_stub(self):
             caps = config.LibvirtConfigCaps()
@@ -3107,11 +3105,13 @@ class HostStateTestCase(test.TestCase):
             return HostStateTestCase.instance_caps
 
     def test_update_status(self):
+        virtapi = fake.FakeVirtAPI()
         self.mox.StubOutWithMock(libvirt_driver, 'LibvirtDriver')
-        libvirt_driver.LibvirtDriver(True).AndReturn(self.FakeConnection())
+        libvirt_driver.LibvirtDriver(virtapi, True).AndReturn(
+            self.FakeConnection())
 
         self.mox.ReplayAll()
-        hs = libvirt_driver.HostState(True)
+        hs = libvirt_driver.HostState(virtapi, True)
         stats = hs._stats
         self.assertEquals(stats["vcpus"], 1)
         self.assertEquals(stats["vcpus_used"], 0)
@@ -3891,7 +3891,8 @@ class LibvirtDriverTestCase(test.TestCase):
     """Test for nova.virt.libvirt.libvirt_driver.LibvirtDriver."""
     def setUp(self):
         super(LibvirtDriverTestCase, self).setUp()
-        self.libvirtconnection = libvirt_driver.LibvirtDriver(read_only=True)
+        self.libvirtconnection = libvirt_driver.LibvirtDriver(
+            fake.FakeVirtAPI(), read_only=True)
 
     def _create_instance(self, params=None):
         """Create a test instance"""
diff --git a/nova/tests/test_powervm.py b/nova/tests/test_powervm.py
index f40ef534c..83a7514db 100644
--- a/nova/tests/test_powervm.py
+++ b/nova/tests/test_powervm.py
@@ -117,7 +117,7 @@ class PowerVMDriverTestCase(test.TestCase):
         super(PowerVMDriverTestCase, self).setUp()
         self.stubs.Set(operator, 'get_powervm_operator',
                        fake_get_powervm_operator)
-        self.powervm_connection = powervm_driver.PowerVMDriver()
+        self.powervm_connection = powervm_driver.PowerVMDriver(None)
         self.instance = self._create_instance()
 
     def _create_instance(self):
diff --git a/nova/tests/test_virt_drivers.py b/nova/tests/test_virt_drivers.py
index ec87c9111..0d3a545d3 100644
--- a/nova/tests/test_virt_drivers.py
+++ b/nova/tests/test_virt_drivers.py
@@ -20,12 +20,14 @@ import sys
 import traceback
 
 from nova.compute.manager import ComputeManager
+from nova import db
 from nova import exception
 from nova.openstack.common import importutils
 from nova.openstack.common import log as logging
 from nova import test
 from nova.tests.image import fake as fake_image
 from nova.tests import utils as test_utils
+from nova.virt import fake
 
 LOG = logging.getLogger(__name__)
 
@@ -171,7 +173,8 @@ class VirtDriverLoaderTestCase(_FakeDriverBackendTestCase):
 class _VirtDriverTestCase(_FakeDriverBackendTestCase):
     def setUp(self):
         super(_VirtDriverTestCase, self).setUp()
-        self.connection = importutils.import_object(self.driver_module, '')
+        self.connection = importutils.import_object(self.driver_module,
+                                                    fake.FakeVirtAPI())
         self.ctxt = test_utils.get_test_admin_context()
         self.image_service = fake_image.FakeImageService()
 
@@ -507,17 +510,7 @@ class _VirtDriverTestCase(_FakeDriverBackendTestCase):
 
 class AbstractDriverTestCase(_VirtDriverTestCase):
     def setUp(self):
-        from nova.virt.driver import ComputeDriver
-
         self.driver_module = "nova.virt.driver.ComputeDriver"
-
-        # TODO(sdague): the abstract driver doesn't have a constructor,
-        # add one now that the loader loads classes directly
-        def __new_init__(self, read_only=False):
-            super(ComputeDriver, self).__init__()
-
-        ComputeDriver.__init__ = __new_init__
-
         super(AbstractDriverTestCase, self).setUp()
 
 
diff --git a/nova/tests/test_vmwareapi.py b/nova/tests/test_vmwareapi.py
index aa28f2762..757ec2bf2 100644
--- a/nova/tests/test_vmwareapi.py
+++ b/nova/tests/test_vmwareapi.py
@@ -50,7 +50,7 @@ class VMWareAPIVMTestCase(test.TestCase):
         vmwareapi_fake.reset()
         db_fakes.stub_out_db_instance_api(self.stubs)
         stubs.set_stubs(self.stubs)
-        self.conn = driver.VMWareESXDriver(False)
+        self.conn = driver.VMWareESXDriver(None, False)
         # NOTE(vish): none of the network plugging code is actually
         #             being tested
         self.network_info = [({'bridge': 'fa0',
diff --git a/nova/tests/test_xenapi.py b/nova/tests/test_xenapi.py
index bd1bcd4f1..94daf0b5c 100644
--- a/nova/tests/test_xenapi.py
+++ b/nova/tests/test_xenapi.py
@@ -40,6 +40,7 @@ from nova.tests import fake_network
 from nova.tests import fake_utils
 import nova.tests.image.fake as fake_image
 from nova.tests.xenapi import stubs
+from nova.virt import fake
 from nova.virt.xenapi import agent
 from nova.virt.xenapi import driver as xenapi_conn
 from nova.virt.xenapi import fake as xenapi_fake
@@ -231,7 +232,7 @@ class XenAPIVolumeTestCase(stubs.XenAPITestBase):
     def test_attach_volume(self):
         """This shows how to test Ops classes' methods."""
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVolumeTests)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         volume = self._create_volume()
         instance = db.instance_create(self.context, self.instance_values)
         vm = xenapi_fake.create_vm(instance.name, 'Running')
@@ -249,7 +250,7 @@ class XenAPIVolumeTestCase(stubs.XenAPITestBase):
         """This shows how to test when exceptions are raised."""
         stubs.stubout_session(self.stubs,
                               stubs.FakeSessionForVolumeFailedTests)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         volume = self._create_volume()
         instance = db.instance_create(self.context, self.instance_values)
         xenapi_fake.create_vm(instance.name, 'Running')
@@ -283,7 +284,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
         self.user_id = 'fake'
         self.project_id = 'fake'
         self.context = context.RequestContext(self.user_id, self.project_id)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         fake_image.stub_out_image_service(self.stubs)
         set_image_fixtures()
@@ -822,7 +823,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
         xenapi_fake.create_vbd(vm_ref, swap_vdi_ref, userdevice=1)
         xenapi_fake.create_vbd(vm_ref, root_vdi_ref, userdevice=0)
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         image_meta = {'id': IMAGE_VHD,
                       'disk_format': 'vhd'}
         conn.rescue(self.context, instance, [], image_meta, '')
@@ -839,7 +840,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
 
     def test_unrescue(self):
         instance = self._create_instance()
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         # Unrescue expects the original instance to be powered off
         conn.power_off(instance)
         rescue_vm = xenapi_fake.create_vm(instance.name + '-rescue', 'Running')
@@ -847,7 +848,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
 
     def test_unrescue_not_in_rescue(self):
         instance = self._create_instance()
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         # Ensure that it will not unrescue a non-rescued instance.
         self.assertRaises(exception.InstanceNotInRescueMode, conn.unrescue,
                           instance, None)
@@ -863,25 +864,25 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
             def finish_revert_migration(self, instance):
                 self.finish_revert_migration_called = True
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         conn._vmops = VMOpsMock()
         conn.finish_revert_migration(instance, None)
         self.assertTrue(conn._vmops.finish_revert_migration_called)
 
     def test_reboot_hard(self):
         instance = self._create_instance()
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         conn.reboot(instance, None, "HARD")
 
     def test_reboot_soft(self):
         instance = self._create_instance()
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         conn.reboot(instance, None, "SOFT")
 
     def test_reboot_halted(self):
         session = xenapi_conn.XenAPISession('test_url', 'root', 'test_pass')
         instance = self._create_instance(spawn=False)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         xenapi_fake.create_vm(instance.name, 'Halted')
         conn.reboot(instance, None, "SOFT")
         vm_ref = vm_utils.lookup(session, instance.name)
@@ -890,7 +891,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
 
     def test_reboot_unknown_state(self):
         instance = self._create_instance(spawn=False)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         xenapi_fake.create_vm(instance.name, 'Unknown')
         self.assertRaises(xenapi_fake.Failure, conn.reboot, instance,
                 None, "SOFT")
@@ -1019,7 +1020,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests,
                               product_version=(6, 0, 0),
                               product_brand='XenServer')
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         vdi_ref = xenapi_fake.create_vdi('hurr', 'fake')
         vdi_uuid = xenapi_fake.get_record('VDI', vdi_ref)['uuid']
         conn._vmops._resize_instance(instance,
@@ -1038,7 +1039,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests,
                               product_version=(1, 4, 99),
                               product_brand='XCP')
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         vdi_ref = xenapi_fake.create_vdi('hurr', 'fake')
         vdi_uuid = xenapi_fake.get_record('VDI', vdi_ref)['uuid']
         conn._vmops._resize_instance(instance,
@@ -1049,7 +1050,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
         instance = db.instance_create(self.context, self.instance_values)
         xenapi_fake.create_vm(instance.name, 'Running')
         instance_type = db.instance_type_get_by_name(self.context, 'm1.large')
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         conn.migrate_disk_and_power_off(self.context, instance,
                                         '127.0.0.1', instance_type, None)
 
@@ -1062,7 +1063,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
             raise exception.MigrationError(reason='test failure')
         self.stubs.Set(vmops.VMOps, "_migrate_vhd", fake_raise)
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.assertRaises(exception.MigrationError,
                           conn.migrate_disk_and_power_off,
                           self.context, instance,
@@ -1092,7 +1093,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
                               product_version=(4, 0, 0),
                               product_brand='XenServer')
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         network_info = fake_network.fake_get_instance_nw_info(self.stubs,
                                                               spectacular=True)
         image_meta = {'id': instance.image_ref, 'disk_format': 'vhd'}
@@ -1127,7 +1128,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
                               product_version=(4, 0, 0),
                               product_brand='XenServer')
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         network_info = fake_network.fake_get_instance_nw_info(self.stubs,
                                                               spectacular=True)
         image_meta = {'id': instance.image_ref, 'disk_format': 'vhd'}
@@ -1149,7 +1150,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
 
         self.stubs.Set(stubs.FakeSessionForVMTests,
                        "VDI_resize_online", fake_vdi_resize)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         network_info = fake_network.fake_get_instance_nw_info(self.stubs,
                                                               spectacular=True)
         image_meta = {'id': instance.image_ref, 'disk_format': 'vhd'}
@@ -1165,7 +1166,7 @@ class XenAPIMigrateInstance(stubs.XenAPITestBase):
 
         self.stubs.Set(stubs.FakeSessionForVMTests,
                        "VDI_resize_online", fake_vdi_resize)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         network_info = fake_network.fake_get_instance_nw_info(self.stubs,
                                                               spectacular=True)
         # Resize instance would be determined by the compute call
@@ -1256,7 +1257,7 @@ class XenAPIHostTestCase(stubs.XenAPITestBase):
                    xenapi_connection_password='test_pass')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         xenapi_fake.create_local_srs()
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
     def test_host_state(self):
         stats = self.conn.get_host_stats()
@@ -1347,7 +1348,7 @@ class XenAPIAutoDiskConfigTestCase(stubs.XenAPITestBase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         self.user_id = 'fake'
         self.project_id = 'fake'
@@ -1440,7 +1441,7 @@ class XenAPIGenerateLocal(stubs.XenAPITestBase):
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         db_fakes.stub_out_db_instance_api(self.stubs)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         self.user_id = 'fake'
         self.project_id = 'fake'
@@ -1528,7 +1529,7 @@ class XenAPIBWCountersTestCase(stubs.XenAPITestBase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def _fake_get_vif_device_map(vm_rec):
             return vm_rec['_vifmap']
@@ -1661,7 +1662,7 @@ class XenAPIDom0IptablesFirewallTestCase(stubs.XenAPITestBase):
                               test_case=self)
         self.context = context.RequestContext(self.user_id, self.project_id)
         self.network = importutils.import_object(FLAGS.network_manager)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.fw = self.conn._vmops.firewall_driver
 
     def _create_instance_ref(self):
@@ -1987,7 +1988,7 @@ class XenAPIAggregateTestCase(stubs.XenAPITestBase):
         host_ref = xenapi_fake.get_all('host')[0]
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         self.context = context.get_admin_context()
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.compute = importutils.import_object(FLAGS.compute_manager)
         self.api = compute_api.AggregateAPI()
         values = {'name': 'test_aggr',
@@ -2392,7 +2393,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_live_migration_calls_vmops(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_live_migrate(context, instance_ref, dest, post_method,
                               recover_method, block_migration, migrate_data):
@@ -2406,18 +2407,18 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
     def test_pre_live_migration(self):
         # ensure method is present
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.conn.pre_live_migration(None, None, None, None)
 
     def test_post_live_migration_at_destination(self):
         # ensure method is present
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.conn.post_live_migration_at_destination(None, None, None, None)
 
     def test_check_can_live_migrate_destination_with_block_migration(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         self.stubs.Set(vm_utils, "safe_find_sr", lambda _x: "asdf")
 
@@ -2436,7 +2437,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
     def test_check_can_live_migrate_destination_block_migration_fails(self):
         stubs.stubout_session(self.stubs,
                               stubs.FakeSessionForFailedMigrateTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
         self.assertRaises(exception.MigrationError,
                           self.conn.check_can_live_migrate_destination,
                           self.context, {'host': 'host'},
@@ -2445,7 +2446,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_check_can_live_migrate_source_with_block_migrate(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_generate_vdi_map(destination_sr_ref, _vm_ref):
             pass
@@ -2470,7 +2471,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
     def test_check_can_live_migrate_source_with_block_migrate_fails(self):
         stubs.stubout_session(self.stubs,
                               stubs.FakeSessionForFailedMigrateTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_generate_vdi_map(destination_sr_ref, _vm_ref):
             pass
@@ -2497,7 +2498,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_check_can_live_migrate_works(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         class fake_aggregate:
             def __init__(self):
@@ -2514,7 +2515,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_check_can_live_migrate_fails(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         class fake_aggregate:
             def __init__(self):
@@ -2532,7 +2533,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_live_migration(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_get_vm_opaque_ref(instance):
             return "fake_vm"
@@ -2554,7 +2555,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_live_migration_on_failure(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_get_vm_opaque_ref(instance):
             return "fake_vm"
@@ -2581,7 +2582,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_live_migration_calls_post_migration(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_generate_vdi_map(destination_sr_ref, _vm_ref):
             pass
@@ -2608,7 +2609,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_live_migration_with_block_migration_raises_invalid_param(self):
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_get_vm_opaque_ref(instance):
             return "fake_vm"
@@ -2627,7 +2628,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
     def test_live_migration_with_block_migration_fails_migrate_send(self):
         stubs.stubout_session(self.stubs,
                               stubs.FakeSessionForFailedMigrateTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_get_vm_opaque_ref(instance):
             return "fake_vm"
@@ -2661,7 +2662,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
         stubs.stubout_session(self.stubs, Session)
 
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         def fake_get_vm_opaque_ref(instance):
             return "fake_vm"
@@ -2687,7 +2688,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
 
     def test_generate_vdi_map(self):
         stubs.stubout_session(self.stubs, xenapi_fake.SessionBase)
-        conn = xenapi_conn.XenAPIDriver(False)
+        conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         vm_ref = "fake_vm_ref"
 
@@ -2719,7 +2720,7 @@ class XenAPIInjectMetadataTestCase(stubs.XenAPITestBase):
                    firewall_driver='nova.virt.xenapi.firewall.'
                                    'Dom0IptablesFirewallDriver')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
-        self.conn = xenapi_conn.XenAPIDriver(False)
+        self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
         self.xenstore = dict(persist={}, ephem={})
 
@@ -2890,7 +2891,7 @@ class VMOpsTestCase(test.TestCase):
 
     def test_check_resize_func_name_defaults_to_VDI_resize(self):
         session = self._get_mock_session(None, None)
-        ops = vmops.VMOps(session)
+        ops = vmops.VMOps(session, fake.FakeVirtAPI())
 
         self.assertEquals(
             'VDI.resize',
diff --git a/nova/virt/baremetal/driver.py b/nova/virt/baremetal/driver.py
index 166eacba6..c38b0f98b 100644
--- a/nova/virt/baremetal/driver.py
+++ b/nova/virt/baremetal/driver.py
@@ -37,7 +37,6 @@ from nova.compute import instance_types
 from nova.compute import power_state
 from nova.compute import vm_states
 from nova import context as nova_context
-from nova import db
 from nova import exception
 from nova import flags
 from nova import notifications
@@ -78,11 +77,11 @@ def _late_load_cheetah():
 
 class BareMetalDriver(driver.ComputeDriver):
 
-    def __init__(self, read_only):
+    def __init__(self, virtapi, read_only):
         _late_load_cheetah()
         # Note that baremetal doesn't have a read-only connection
         # mode, so the read_only parameter is ignored
-        super(BareMetalDriver, self).__init__()
+        super(BareMetalDriver, self).__init__(virtapi)
         self.baremetal_nodes = nodes.get_baremetal_nodes()
         self._wrapped_conn = None
         self._host_state = None
@@ -230,7 +229,7 @@ class BareMetalDriver(driver.ComputeDriver):
             try:
                 LOG.debug(_("Key is injected but instance is not running yet"),
                           instance=instance)
-                (old_ref, new_ref) = db.instance_update_and_get_original(
+                (old_ref, new_ref) = self.virtapi.instance_update(
                         context, instance['uuid'],
                         {'vm_state': vm_states.BUILDING})
                 notifications.send_update(context, old_ref, new_ref)
@@ -239,7 +238,7 @@ class BareMetalDriver(driver.ComputeDriver):
                 if state == power_state.RUNNING:
                     LOG.debug(_('instance %s: booted'), instance['name'],
                               instance=instance)
-                    (old_ref, new_ref) = db.instance_update_and_get_original(
+                    (old_ref, new_ref) = self.virtapi.instance_update(
                             context, instance['uuid'],
                             {'vm_state': vm_states.ACTIVE})
                     notifications.send_update(context, old_ref, new_ref)
@@ -254,7 +253,7 @@ class BareMetalDriver(driver.ComputeDriver):
             except Exception:
                 LOG.exception(_("Baremetal assignment is overcommitted."),
                           instance=instance)
-                (old_ref, new_ref) = db.instance_update_and_get_original(
+                (old_ref, new_ref) = self.virtapi.instance_update(
                         context, instance['uuid'],
                         {'vm_state': vm_states.ERROR,
                          'power_state': power_state.FAILED})
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index c78d063f9..a2e48508c 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -92,6 +92,9 @@ class ComputeDriver(object):
         "has_imagecache": False,
         }
 
+    def __init__(self, virtapi):
+        self.virtapi = virtapi
+
     def init_host(self, host):
         """Initialize anything that is necessary for the driver to function,
         including catching up with currently running VM's on the given host."""
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
index 8c3253adc..4be240792 100644
--- a/nova/virt/fake.py
+++ b/nova/virt/fake.py
@@ -30,6 +30,7 @@ from nova import db
 from nova import exception
 from nova.openstack.common import log as logging
 from nova.virt import driver
+from nova.virt import virtapi
 
 
 LOG = logging.getLogger(__name__)
@@ -52,7 +53,8 @@ class FakeDriver(driver.ComputeDriver):
 
     """Fake hypervisor driver"""
 
-    def __init__(self, read_only=False):
+    def __init__(self, virtapi, read_only=False):
+        super(FakeDriver, self).__init__(virtapi)
         self.instances = {}
         self.host_status = {
           'host_name-description': 'Fake Host',
@@ -329,3 +331,10 @@ class FakeDriver(driver.ComputeDriver):
 
     def get_volume_connector(self, instance):
         return {'ip': '127.0.0.1', 'initiator': 'fake', 'host': 'fakehost'}
+
+
+class FakeVirtAPI(virtapi.VirtAPI):
+    def instance_update(self, context, instance_uuid, updates):
+        return db.instance_update_and_get_original(context,
+                                                   instance_uuid,
+                                                   updates)
diff --git a/nova/virt/hyperv/driver.py b/nova/virt/hyperv/driver.py
index 3f43ca0a6..6d9f66ff8 100644
--- a/nova/virt/hyperv/driver.py
+++ b/nova/virt/hyperv/driver.py
@@ -73,8 +73,8 @@ LOG = logging.getLogger(__name__)
 
 
 class HyperVDriver(driver.ComputeDriver):
-    def __init__(self):
-        super(HyperVDriver, self).__init__()
+    def __init__(self, virtapi):
+        super(HyperVDriver, self).__init__(virtapi)
 
         self._hostops = hostops.HostOps()
         self._volumeops = volumeops.VolumeOps()
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 132a4b744..97ce1710c 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -61,7 +61,6 @@ from nova.compute import instance_types
 from nova.compute import power_state
 from nova.compute import vm_mode
 from nova import context as nova_context
-from nova import db
 from nova import exception
 from nova import flags
 from nova.image import glance
@@ -257,8 +256,8 @@ class LibvirtDriver(driver.ComputeDriver):
         "has_imagecache": True,
         }
 
-    def __init__(self, read_only=False):
-        super(LibvirtDriver, self).__init__()
+    def __init__(self, virtapi, read_only=False):
+        super(LibvirtDriver, self).__init__(virtapi)
 
         global libvirt
         if libvirt is None:
@@ -311,7 +310,7 @@ class LibvirtDriver(driver.ComputeDriver):
     @property
     def host_state(self):
         if not self._host_state:
-            self._host_state = HostState(self.read_only)
+            self._host_state = HostState(self.virtapi, self.read_only)
         return self._host_state
 
     def has_min_version(self, ver):
@@ -1621,7 +1620,7 @@ class LibvirtDriver(driver.ComputeDriver):
 
                 if ephemeral_device is not None:
                     swap_device = self.default_third_device
-                    db.instance_update(
+                    self.virtapi.instance_update(
                         nova_context.get_admin_context(), instance['uuid'],
                         {'default_ephemeral_device':
                              '/dev/' + self.default_second_device})
@@ -1646,7 +1645,7 @@ class LibvirtDriver(driver.ComputeDriver):
                                                   block_device_info)):
                     diskswap = disk_info('disk.swap', swap_device)
                     devices.append(diskswap)
-                    db.instance_update(
+                    self.virtapi.instance_update(
                         nova_context.get_admin_context(), instance['uuid'],
                         {'default_swap_device': '/dev/' + swap_device})
 
@@ -1700,7 +1699,7 @@ class LibvirtDriver(driver.ComputeDriver):
             # NOTE(yamahata):
             # for nova.api.ec2.cloud.CloudController.get_metadata()
             root_device = self.default_root_device
-            db.instance_update(
+            self.virtapi.instance_update(
                 nova_context.get_admin_context(), instance['uuid'],
                 {'root_device_name': '/dev/' + self.default_root_device})
 
@@ -3008,11 +3007,12 @@ class LibvirtDriver(driver.ComputeDriver):
 
 class HostState(object):
     """Manages information about the compute node through libvirt"""
-    def __init__(self, read_only):
+    def __init__(self, virtapi, read_only):
         super(HostState, self).__init__()
         self.read_only = read_only
         self._stats = {}
         self.connection = None
+        self.virtapi = virtapi
         self.update_status()
 
     def get_host_stats(self, refresh=False):
@@ -3027,7 +3027,7 @@ class HostState(object):
         """Retrieve status info from libvirt."""
         LOG.debug(_("Updating host stats"))
         if self.connection is None:
-            self.connection = LibvirtDriver(self.read_only)
+            self.connection = LibvirtDriver(self.virtapi, self.read_only)
         data = {}
         data["vcpus"] = self.connection.get_vcpu_total()
         data["vcpus_used"] = self.connection.get_vcpu_used()
diff --git a/nova/virt/powervm/driver.py b/nova/virt/powervm/driver.py
index cd91a7299..f4f26045e 100644
--- a/nova/virt/powervm/driver.py
+++ b/nova/virt/powervm/driver.py
@@ -18,7 +18,6 @@ from nova.compute import task_states
 from nova.compute import vm_states
 
 from nova import context as nova_context
-from nova import db
 from nova import flags
 
 from nova.openstack.common import cfg
@@ -59,8 +58,8 @@ class PowerVMDriver(driver.ComputeDriver):
 
     """PowerVM Implementation of Compute Driver."""
 
-    def __init__(self):
-        super(PowerVMDriver, self).__init__()
+    def __init__(self, virtapi):
+        super(PowerVMDriver, self).__init__(virtapi)
         self._powervm = operator.PowerVMOperator()
 
     @property
diff --git a/nova/virt/virtapi.py b/nova/virt/virtapi.py
new file mode 100644
index 000000000..15a45b7d9
--- /dev/null
+++ b/nova/virt/virtapi.py
@@ -0,0 +1,30 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    Copyright 2012 IBM Corp.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+from nova import db
+
+
+class VirtAPI(object):
+    def instance_update(self, context, instance_uuid, updates):
+        """Perform an instance update operation on behalf of a virt driver
+        :param context: security context
+        :param instance_uuid: uuid of the instance to be updated
+        :param updates: dict of attribute=value pairs to change
+
+        Returns: orig_instance, new_instance
+        """
+        raise NotImplementedError()
diff --git a/nova/virt/vmwareapi/driver.py b/nova/virt/vmwareapi/driver.py
index ec8673418..e56f81213 100644
--- a/nova/virt/vmwareapi/driver.py
+++ b/nova/virt/vmwareapi/driver.py
@@ -100,8 +100,8 @@ class Failure(Exception):
 class VMWareESXDriver(driver.ComputeDriver):
     """The ESX host connection object."""
 
-    def __init__(self, read_only=False, scheme="https"):
-        super(VMWareESXDriver, self).__init__()
+    def __init__(self, virtapi, read_only=False, scheme="https"):
+        super(VMWareESXDriver, self).__init__(virtapi)
 
         host_ip = FLAGS.vmwareapi_host_ip
         host_username = FLAGS.vmwareapi_host_username
diff --git a/nova/virt/xenapi/driver.py b/nova/virt/xenapi/driver.py
index 2ae4c27e9..612ae7f41 100644
--- a/nova/virt/xenapi/driver.py
+++ b/nova/virt/xenapi/driver.py
@@ -125,8 +125,8 @@ FLAGS.register_opts(xenapi_opts)
 class XenAPIDriver(driver.ComputeDriver):
     """A connection to XenServer or Xen Cloud Platform"""
 
-    def __init__(self, read_only=False):
-        super(XenAPIDriver, self).__init__()
+    def __init__(self, virtapi, read_only=False):
+        super(XenAPIDriver, self).__init__(virtapi)
 
         url = FLAGS.xenapi_connection_url
         username = FLAGS.xenapi_connection_username
@@ -141,7 +141,7 @@ class XenAPIDriver(driver.ComputeDriver):
         self._volumeops = volumeops.VolumeOps(self._session)
         self._host_state = None
         self._host = host.Host(self._session)
-        self._vmops = vmops.VMOps(self._session)
+        self._vmops = vmops.VMOps(self._session, self.virtapi)
         self._initiator = None
         self._hypervisor_hostname = None
         self._pool = pool.ResourcePool(self._session)
diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index 1f8cafa3b..7ccb23283 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -93,7 +93,7 @@ def cmp_version(a, b):
     return len(a) - len(b)
 
 
-def make_step_decorator(context, instance):
+def make_step_decorator(context, instance, instance_update):
     """Factory to create a decorator that records instance progress as a series
     of discrete steps.
 
@@ -125,7 +125,7 @@ def make_step_decorator(context, instance):
                          step_info['total'] * 100)
         LOG.debug(_("Updating progress to %(progress)d"), locals(),
                   instance=instance)
-        db.instance_update(context, instance['uuid'], {'progress': progress})
+        instance_update(context, instance['uuid'], {'progress': progress})
 
     def step_decorator(f):
         step_info['total'] += 1
@@ -145,9 +145,10 @@ class VMOps(object):
     """
     Management class for VM-related tasks
     """
-    def __init__(self, session):
+    def __init__(self, session, virtapi):
         self.compute_api = compute.API()
         self._session = session
+        self._virtapi = virtapi
         self.poll_rescue_last_ran = None
         self.firewall_driver = firewall.load_driver(
             default=DEFAULT_FIREWALL_DRIVER,
@@ -254,7 +255,8 @@ class VMOps(object):
         if name_label is None:
             name_label = instance['name']
 
-        step = make_step_decorator(context, instance)
+        step = make_step_decorator(context, instance,
+                                   self._virtapi.instance_update)
 
         @step
         def determine_disk_image_type_step(undo_mgr):
@@ -454,7 +456,8 @@ class VMOps(object):
 
         if instance['vm_mode'] != mode:
             # Update database with normalized (or determined) value
-            db.instance_update(context, instance['uuid'], {'vm_mode': mode})
+            self._virtapi.instance_update(context,
+                                          instance['uuid'], {'vm_mode': mode})
 
         vm_ref = vm_utils.create_vm(self._session, instance, name_label,
                                     kernel_file, ramdisk_file, use_pv_kernel)
@@ -661,7 +664,8 @@ class VMOps(object):
         progress = round(float(step) / total_steps * 100)
         LOG.debug(_("Updating progress to %(progress)d"), locals(),
                   instance=instance)
-        db.instance_update(context, instance['uuid'], {'progress': progress})
+        self._virtapi.instance_update(context, instance['uuid'],
+                                      {'progress': progress})
 
     def _migrate_disk_resizing_down(self, context, instance, dest,
                                     instance_type, vm_ref, sr_path):