diff --git a/watcher/decision_engine/model/collector/nova.py b/watcher/decision_engine/model/collector/nova.py
index 092024d59..699fb9ab4 100644
--- a/watcher/decision_engine/model/collector/nova.py
+++ b/watcher/decision_engine/model/collector/nova.py
@@ -79,7 +79,7 @@ class NovaClusterDataModelCollector(base.BaseClusterDataModelCollector):
                 instance = element.Instance()
                 instance.uuid = v.id
                 # nova/nova/compute/instance_states.py
-                instance.state = getattr(v, 'OS-EXT-STS:instance_state')
+                instance.state = getattr(v, 'OS-EXT-STS:vm_state')
 
                 # set capacity
                 self.wrapper.get_flavor_instance(v, flavor_cache)
diff --git a/watcher/tests/decision_engine/cluster/test_nova_cdmc.py b/watcher/tests/decision_engine/cluster/test_nova_cdmc.py
index 8f121f367..f236b5e29 100644
--- a/watcher/tests/decision_engine/cluster/test_nova_cdmc.py
+++ b/watcher/tests/decision_engine/cluster/test_nova_cdmc.py
@@ -47,7 +47,7 @@ class TestNovaClusterDataModelCollector(base.TestCase):
         )
         fake_instance = mock.Mock(
             id='ef500f7e-dac8-470f-960c-169486fce71b',
-            state=mock.Mock(**{'OS-EXT-STS:instance_state': 'VM_STATE'}),
+            state=mock.Mock(**{'OS-EXT-STS:vm_state': 'VM_STATE'}),
             flavor={'ram': 333, 'disk': 222, 'vcpus': 4},
         )
         m_nova_helper.get_compute_node_list.return_value = [fake_compute_node]