title: How to solve redis cluster "Waiting for the cluster to join" issue?
body: <p>I have 3 machines and create 6 nodes for redis cluster, i have created it successfully months ago, but it dropped now, i try my best to fix it, but it not work, so i clean all data and re-create it from zero,when i use following command to create cluster, it block here, and waiting node join cluster, i do some research for it, i clean my data, log again and again, do it again and again, but it still not work. </p>
  
  <pre><code>redis-trib.rb create --replicas 1 10.2.1.208:6379 10.2.1.208:6380 10.2.1.209:6379 10.2.1.209:6380 10.2.1.15:6379 10.2.1.15:6380
  </code></pre>
  
  <p><a href="http://i.stack.imgur.com/6W3Z0.png" rel="noreferrer">show the result</a></p>
  
  <pre><code>redis-trib.rb create --replicas 1 10.2.1.208:6379 10.2.1.208:6380 10.2.1.209:6379 10.2.1.209:6380 10.2.1.15:6379 10.2.1.15:6380
  &gt;&gt;&gt; Creating cluster
  &gt;&gt;&gt; Performing hash slots allocation on 6 nodes...
  Using 3 masters:
  10.2.1.208:6379
  10.2.1.209:6379
  10.2.1.15:6379
  Adding replica 10.2.1.209:6380 to 10.2.1.208:6379
  Adding replica 10.2.1.208:6380 to 10.2.1.209:6379
  Adding replica 10.2.1.15:6380 to 10.2.1.15:6379
  M: 73b3b99bb17de63aa99eaf592376f0a06feb3d66 10.2.1.208:6379
     slots:0-5460 (5461 slots) master
  S: 05b33ed6691797faaf7ccec1541396472b9d2866 10.2.1.208:6380
     replicates f14702ebb1462b313dd7eb4809ec50e30e4eef36
  M: f14702ebb1462b313dd7eb4809ec50e30e4eef36 10.2.1.209:6379
     slots:5461-10922 (5462 slots) master
  S: 3a9f433a8503281b0ddfc6ec69016908735053b8 10.2.1.209:6380
     replicates 73b3b99bb17de63aa99eaf592376f0a06feb3d66
  M: 2fd97e8842828dba6b425b6a30e764fb06915737 10.2.1.15:6379
     slots:10923-16383 (5461 slots) master
  S: c46db592d49bc1e9d8b5efb27b9799929c5186a4 10.2.1.15:6380
     replicates 2fd97e8842828dba6b425b6a30e764fb06915737
  Can I set the above configuration? (type 'yes' to accept): yes
  &gt;&gt;&gt; Nodes configuration updated
  &gt;&gt;&gt; Assign a different config epoch to each node
  &gt;&gt;&gt; Sending CLUSTER MEET messages to join the cluster
  Waiting for the cluster to join...........................................................................^C/usr/local/bin/redis-trib.rb:652:in `sleep': Interrupt
          from /usr/local/bin/redis-trib.rb:652:in `wait_cluster_join'
          from /usr/local/bin/redis-trib.rb:1305:in `create_cluster_cmd'
          from /usr/local/bin/redis-trib.rb:1695:in `&lt;main&gt;'
  </code></pre>