diff --git a/internal/distributed/connection_manager.go b/internal/distributed/connection_manager.go
index 48fb56c006..f65ba301a9 100644
--- a/internal/distributed/connection_manager.go
+++ b/internal/distributed/connection_manager.go
@@ -88,6 +88,7 @@ func NewConnectionManager(session *sessionutil.Session) *ConnectionManager {
 	}
 }
 
+// AddDependency add a dependency by role name.
 func (cm *ConnectionManager) AddDependency(roleName string) error {
 	if !cm.checkroleName(roleName) {
 		return errors.New("roleName is illegal")