title: Elasticsearch: failed to validate incoming join request from node
body: <p>With Elasticsearch, I'm trying to set up a simple master-1 node with data-1 and data-2 nodes but when I look at the log I get this error :</p>
  <p><a href="http://puu.sh/FZQwv/3f31394ba7.png" rel="nofollow noreferrer">I get this error http://puu.sh/FZQwv/3f31394ba7.png</a>
  All nodes are fresh CentOS 7 machines that can ping each other. For all the clusters I've set:</p>
  <pre><code>cluster.name: playground
  node.name:  &lt;their name master-1/data-1/data-2&gt;
  network.host: [_local_,_site_]
  http.port: 9200 
  discovery.seed_hosts: [&quot;&lt;internal IP of master&gt;&quot;]
  cluster.initial_master_nodes: [&quot;master-1&quot;]
  (at the end):
  node.master: (only true for master-1)
  node.data: true
  node.ingest: false
  node.ml: false
  </code></pre>
  <p>Does anyone knows what's going on?</p>