anchor.diff:  [float]
   ==== unicast_hosts.txt file format
   
  -The format of the file is to specify one unicast host entry per line.  
  +The format of the file is to specify one unicast host entry per line.
   Each unicast host entry consists of the host (host name or IP address) and
  -an optional transport port number.  If the port number is specified, is must 
  -come immediately after the host (on the same line) separated by a `:`. 
  -If the port number is not specified, a default value of 9300 is used.  
  +an optional transport port number.  If the port number is specified, is must
  +come immediately after the host (on the same line) separated by a `:`.
  +If the port number is not specified, a default value of 9300 is used.
   
   For example, this is an example of `unicast_hosts.txt` for a cluster with
   four nodes that participate in unicast discovery, some of which are not
  
positive.code: [[discovery-file]]
  === File-Based Discovery Plugin
  
  The file-based discovery plugin uses a list of hosts/ports in a `unicast_hosts.txt` file 
  in the `config/discovery-file` directory for unicast discovery.
  
  [[discovery-file-install]]
  
negative.code: [float]
  ==== Using the file-based discovery plugin
  
  The file-based discovery plugin provides the ability to specify the
  unicast hosts list through a simple `unicast_hosts.txt` file that can
  be dynamically updated at any time. To enable, add the following in `elasticsearch.yml`:
  
  