title: redis-cluster - add-node slave to existing cluster from remote machine hanging forever
body: <p>I am trying to connect a cluster of 8 replicas on one address to an existing cluster on another address.</p>
  
  <p>The replica servers are all running in cluster mode.</p>
  
  <p>When I try to do either:</p>
  
  <p><code>./redis-trib.rb add-node --slave REPLICA_IP:6380 MASTER_IP:6380</code></p>
  
  <p>or</p>
  
  <p><code>./redis-cli --cluster add-node REPLICA_IP:6380 MASTER_IP:6380 --cluster-slave</code></p>
  
  <p>I get the same result; </p>
  
  <p><code>Waiting for the cluster to join...........................</code></p>
  
  <p>which hangs indefinitely. </p>
  
  <p>The two servers can definitely see each other and I can connect to any relevant redis-node (replica or master) from either server. The discovery/communion ports (16830, etc.) are all open and contactable as well. The output of these commands also suggests that the cluster has been found as it shows each of the nodes and their correct node ids.</p>
  
  <p>here is the full output of either add-node command:</p>
  
  <pre><code>&gt;&gt;&gt; Adding node REPLICA_IP:6380 to cluster MASTER_IP:6380
  &gt;&gt;&gt; Performing Cluster Check (using node MASTER_IP:6380)
  M: 043a5fa4fdca929d3d87f953906dc7c1f030926c MASTER_IP:6380
     slots:[0-2047] (2048 slots) master
  M: e104777d31630eef11a01e41c7d3a6c98e14ab64 MASTER_IP:6386
     slots:[12288-14335] (2048 slots) master
  M: 9c807d6f57a9634adcdf75fa1943c32c985bda1c MASTER_IP:6384
     slots:[8192-10239] (2048 slots) master
  M: 0f7ec07deff97ca23fe67109da2365d916ff1a67 MASTER_IP:6383
     slots:[6144-8191] (2048 slots) master
  M: 974e8b4051b7a8e33db62ba7ad62c7e54abe699d MASTER_IP:6382
     slots:[4096-6143] (2048 slots) master
  M: b647bb9d732ff2ee83b097ffb8b49fb2bccd366f MASTER_IP:6387
     slots:[14336-16383] (2048 slots) master
  M: a86ac1d5e783bed133b153e471fdd970c17c6af5 MASTER_IP:6381
     slots:[2048-4095] (2048 slots) master
  M: 6f859b03f86eded0188ba493063c5c2114d7c11f MASTER_IP:6385
     slots:[10240-12287] (2048 slots) master
  [OK] All nodes agree about slots configuration.
  &gt;&gt;&gt; Check for open slots...
  &gt;&gt;&gt; Check slots coverage...
  [OK] All 16384 slots covered.
  Automatically selected master MASTER_IP:6380
  &gt;&gt;&gt; Send CLUSTER MEET to node REPLICA_IP:6380 to make it join the cluster.
  Waiting for the cluster to join
  ............................
  </code></pre>
  
  <p>If I run <code>CLUSTER MEET</code> manually and then <code>CLUSTER NODES</code> I can temporarily see another node in state 'handshake' with status 'disconnected' and then it disappears. It shows a node id that is not the same as it actually is.</p>