diff --git a/blazar/plugins/oshosts/host_plugin.py b/blazar/plugins/oshosts/host_plugin.py
index 7cb03d1b..44c57de8 100644
--- a/blazar/plugins/oshosts/host_plugin.py
+++ b/blazar/plugins/oshosts/host_plugin.py
@@ -696,19 +696,17 @@ class PhysicalHostMonitorPlugin(base.BaseMonitorPlugin,
 
         :return: a list of failed hosts.
         """
-        failed_hosts = []
-        hosts = db_api.reservable_host_get_all_by_queries([])
-        for host in hosts:
-            with trusts.create_ctx_from_trust(host['trust_id']):
-                try:
-                    hv = self.nova.hypervisors.get(host['id'])
-                    LOG.debug('%s: state=%s, status=%s.',
-                              hv.hypervisor_hostname, hv.state, hv.status)
-                    if hv.state == 'down' or hv.status == 'disabled':
-                        failed_hosts.append(host)
-                except Exception as e:
-                    LOG.exception('Skipping health check of host %s. %s',
-                                  host['hypervisor_hostname'], str(e))
+        reservable_hosts = db_api.reservable_host_get_all_by_queries([])
+
+        try:
+            hvs = self.nova.hypervisors.list()
+            failed_hv_ids = [str(hv.id) for hv in hvs
+                             if hv.state == 'down' or hv.status == 'disabled']
+            failed_hosts = [host for host in reservable_hosts
+                            if host['id'] in failed_hv_ids]
+        except Exception as e:
+            LOG.exception('Skipping health check of host %s. %s',
+                          host['hypervisor_hostname'], str(e))
 
         return failed_hosts
 
diff --git a/blazar/tests/plugins/test_physical_host_plugin.py b/blazar/tests/plugins/test_physical_host_plugin.py
index d211b92d..9236886c 100644
--- a/blazar/tests/plugins/test_physical_host_plugin.py
+++ b/blazar/tests/plugins/test_physical_host_plugin.py
@@ -1670,9 +1670,6 @@ class PhysicalHostMonitorPluginTestCase(tests.TestCase):
     def setUp(self):
         super(PhysicalHostMonitorPluginTestCase, self).setUp()
         self.patch(nova_client, 'Client')
-        self.patch(base, 'url_for').return_value = 'http://foo.bar'
-        self.patch(context, 'BlazarContext')
-        self.patch(trusts, 'create_ctx_from_trust')
         self.host_monitor_plugin = host_plugin.PhysicalHostMonitorPlugin()
 
     def test_notification_callback_disabled_true(self):
@@ -1751,10 +1748,11 @@ class PhysicalHostMonitorPluginTestCase(tests.TestCase):
         host_get_all = self.patch(db_api,
                                   'reservable_host_get_all_by_queries')
         host_get_all.return_value = hosts
-        hypervisor_get = self.patch(self.host_monitor_plugin.nova.hypervisors,
-                                    'get')
-        hypervisor_get.return_value = mock.MagicMock(state='down',
-                                                     status='enabled')
+        hypervisors_list = self.patch(
+            self.host_monitor_plugin.nova.hypervisors, 'list')
+        hypervisors_list.return_value = [
+            mock.MagicMock(id=1, state='down', status='enabled'),
+            mock.MagicMock(id=2, state='down', status='enabled')]
 
         result = self.host_monitor_plugin._poll_resource_failures()
         self.assertEqual(hosts, result)
@@ -1772,10 +1770,11 @@ class PhysicalHostMonitorPluginTestCase(tests.TestCase):
         host_get_all = self.patch(db_api,
                                   'reservable_host_get_all_by_queries')
         host_get_all.return_value = hosts
-        hypervisor_get = self.patch(self.host_monitor_plugin.nova.hypervisors,
-                                    'get')
-        hypervisor_get.return_value = mock.MagicMock(state='up',
-                                                     status='disabled')
+        hypervisors_list = self.patch(
+            self.host_monitor_plugin.nova.hypervisors, 'list')
+        hypervisors_list.return_value = [
+            mock.MagicMock(id=1, state='up', status='disabled'),
+            mock.MagicMock(id=2, state='up', status='disabled')]
 
         result = self.host_monitor_plugin._poll_resource_failures()
         self.assertEqual(hosts, result)
@@ -1793,10 +1792,11 @@ class PhysicalHostMonitorPluginTestCase(tests.TestCase):
         host_get_all = self.patch(db_api,
                                   'reservable_host_get_all_by_queries')
         host_get_all.return_value = hosts
-        hypervisor_get = self.patch(self.host_monitor_plugin.nova.hypervisors,
-                                    'get')
-        hypervisor_get.return_value = mock.MagicMock(state='up',
-                                                     status='enabled')
+        hypervisors_list = self.patch(
+            self.host_monitor_plugin.nova.hypervisors, 'list')
+        hypervisors_list.return_value = [
+            mock.MagicMock(id=1, state='up', status='enabled'),
+            mock.MagicMock(id=2, state='up', status='enabled')]
 
         result = self.host_monitor_plugin._poll_resource_failures()
         self.assertEqual([], result)
diff --git a/blazar/tests/utils/openstack/test_nova.py b/blazar/tests/utils/openstack/test_nova.py
index 280ede9f..4773d155 100644
--- a/blazar/tests/utils/openstack/test_nova.py
+++ b/blazar/tests/utils/openstack/test_nova.py
@@ -57,9 +57,10 @@ class TestCNClient(tests.TestCase):
         user_domain = 'User_Domain'
         project_name = 'admin'
         project_domain = 'Project_Domain'
-        auth_url = "%s://%s:%s/v3" % (CONF.os_auth_protocol,
+        auth_url = "%s://%s:%s/%s" % (CONF.os_auth_protocol,
                                       CONF.os_auth_host,
-                                      CONF.os_auth_port)
+                                      CONF.os_auth_port,
+                                      CONF.os_auth_prefix)
 
         kwargs = {'version': self.version,
                   'endpoint_override': endpoint,
diff --git a/blazar/utils/openstack/nova.py b/blazar/utils/openstack/nova.py
index cfc9e0c1..e3139898 100644
--- a/blazar/utils/openstack/nova.py
+++ b/blazar/utils/openstack/nova.py
@@ -126,9 +126,10 @@ class BlazarNovaClient(object):
                                     os_region_name=CONF.os_region_name)
 
         if auth_url is None:
-            auth_url = "%s://%s:%s/v3" % (CONF.os_auth_protocol,
+            auth_url = "%s://%s:%s/%s" % (CONF.os_auth_protocol,
                                           CONF.os_auth_host,
-                                          CONF.os_auth_port)
+                                          CONF.os_auth_port,
+                                          CONF.os_auth_prefix)
 
         if username:
             kwargs.setdefault('username', username)
@@ -191,9 +192,7 @@ class NovaClientWrapper(object):
 
     @property
     def nova(self):
-        ctx = context.current()
-        nova = BlazarNovaClient(ctx=ctx,
-                                username=self.username,
+        nova = BlazarNovaClient(username=self.username,
                                 password=self.password,
                                 user_domain_name=self.user_domain_name,
                                 project_name=self.project_name,