diff --git a/dragonflow/db/api_nb.py b/dragonflow/db/api_nb.py
index a334bf89f..a10b92eac 100644
--- a/dragonflow/db/api_nb.py
+++ b/dragonflow/db/api_nb.py
@@ -122,6 +122,12 @@ class NbApi(object):
                     self.db_change_callback)
                 self.subscriber.register_hamsg_for_db()
 
+    def close(self):
+        if self.publisher:
+            self.publisher.close()
+        if self.subscriber:
+            self.subscriber.close()
+
     def db_recover_callback(self):
         # only db with HA func can go in here
         self.driver.process_ha()