diff --git a/xCAT-client/pods/man1/updatenode.1.pod b/xCAT-client/pods/man1/updatenode.1.pod
index 35c419984..fb7478a2c 100644
--- a/xCAT-client/pods/man1/updatenode.1.pod
+++ b/xCAT-client/pods/man1/updatenode.1.pod
@@ -345,7 +345,8 @@ Display usage message.
 =item B<-k|--security>
 
 Update the ssh keys and host keys for the service nodes and compute nodes;
-Update the ca and credentials to the service nodes.  Never run this command to the Management Node, it will take down xcatd. 
+Update the ca and credentials to the service nodes.  Never run this command to the Management Node, it will take down xcatd.
+You must be running updatenode as root to use the -k flag. 
 
 =item B<-l>|B<--user> I<user_ID>