diff --git a/watcher/conf/nova_client.py b/watcher/conf/nova_client.py
index 35d55fdb5..5ae78ae0c 100755
--- a/watcher/conf/nova_client.py
+++ b/watcher/conf/nova_client.py
@@ -23,7 +23,7 @@ nova_client = cfg.OptGroup(name='nova_client',
 
 NOVA_CLIENT_OPTS = [
     cfg.StrOpt('api_version',
-               default='2',
+               default='2.53',
                help='Version of Nova API to use in novaclient.'),
     cfg.StrOpt('endpoint_type',
                default='publicURL',
diff --git a/watcher/decision_engine/model/element/node.py b/watcher/decision_engine/model/element/node.py
index 3807a6ff1..cc33909a4 100644
--- a/watcher/decision_engine/model/element/node.py
+++ b/watcher/decision_engine/model/element/node.py
@@ -33,7 +33,7 @@ class ServiceState(enum.Enum):
 class ComputeNode(compute_resource.ComputeResource):
 
     fields = {
-        "id": wfields.NonNegativeIntegerField(),
+        "id": wfields.StringField(),
         "hostname": wfields.StringField(),
         "status": wfields.StringField(default=ServiceState.ENABLED.value),
         "state": wfields.StringField(default=ServiceState.ONLINE.value),