diff --git a/docs/bgp.md b/docs/bgp.md
index e7b83e331a..471e0fce7e 100644
--- a/docs/bgp.md
+++ b/docs/bgp.md
@@ -62,6 +62,8 @@ for Route Reflector client mode.
 
 Only nodes with the same ClusterID in client and server mode will peer together.
 
+When joining new nodes to the cluster, remember to annotate them with `kube-router.io/rr.client=42`, and then restart kube-router on the new nodes and the route reflector server nodes to let them successfully read the annotations and peer with each other.
+
 ## Peering Outside The Cluster
 ### Global External BGP Peers