diff --git a/nova/availability_zones.py b/nova/availability_zones.py
index d627fa0d7..04704b323 100644
--- a/nova/availability_zones.py
+++ b/nova/availability_zones.py
@@ -47,8 +47,10 @@ def _get_cache():
     return MC
 
 
-def _reset_cache():
-    """Reset the cache, mainly for testing purposes."""
+def reset_cache():
+    """Reset the cache, mainly for testing purposes and update
+    availability_zone for host aggregate
+    """
 
     global MC