anchor.diff:  
   [source,bash]
   --------------------------------------------------
  -$ bin/elasticsearch -Ecluster.initial_master_nodes=master-a,master-b,master-c
  +bin/elasticsearch -E cluster.initial_master_nodes=master-a,master-b,master-c
   --------------------------------------------------
   
  -[NOTE]
  -==================================================
  -
  -[[modules-discovery-bootstrap-cluster-fqdns]] The node names used in the
  +[[modules-discovery-bootstrap-cluster-fqdns]]
  +.Node name formats must match
  +****
  +The node names used in the
   `cluster.initial_master_nodes` list must exactly match the `node.name`
   properties of the nodes. By default the node name is set to the machine's
   hostname which may or may not be fully-qualified depending on your system
  
positive.code: * Configure `cluster.initial_master_nodes` as described above.
  * Restart all the nodes and verify that they have formed a single cluster.
  
  ==================================================
  
negative.code: * `discovery.seed_hosts`
  * `cluster.initial_master_nodes`
  
  [[modules-discovery-bootstrap-cluster-joining]]
  .Forming a single cluster
  ****
  If you start an {es} node
  without configuring these settings then it will start up in development mode and
  auto-bootstrap itself into a new cluster. If you start some {es} nodes on
  different hosts then by default they will not discover each other and will form
  