title: Apply security on ELK Cluster - authentication issue
body: <p>I have a 7.6.2 cluster of three nodes and want to apply the x-pack security. So I've updated my elasticsearch.yml conf.
  I first want to set password</p>
  
  <pre><code>/usr/share/elasticsearch/bin/elasticsearch-setup-passwords auto
  
  Unexpected response code [405] from calling GET http://xxx:9200/_security/_authenticate?pretty
  It doesn't look like the X-Pack security feature is enabled on this Elasticsearch node.
  Please check if you have enabled X-Pack security in your elasticsearch.yml configuration file.
  
  ERROR: X-Pack Security is disabled by configuration.
  </code></pre>
  
  <p>But it fails, so I restart one elasticsearch node, but then still impossible to set password</p>
  
  <pre><code>/etc/elasticsearch$ /usr/share/elasticsearch/bin/elasticsearch-setup-passwords auto
  
  Your cluster health is currently RED.
  This means that some cluster data is unavailable and your cluster is not fully functional.
  
  It is recommended that you resolve the issues with your cluster before running elasticsearch-setup-passwords.
  It is very likely that the password changes will fail when run against an unhealthy cluster.
  
  Do you want to continue with the password setup process [y/N]y
  
  Initiating the setup of passwords for reserved users elastic,apm_system,kibana,logstash_system,beats_system,remote_monitoring_user.
  The passwords will be randomly generated and printed to the console.
  Please confirm that you would like to continue [y/N]y
  
  
  
  Connection failure to: http://xxx:9200/_security/user/apm_system/_password?pretty failed: Read timed out
  
  ERROR:Failed to set password for user [apm_system].
  </code></pre>
  
  <p>And I'm not able to access anything as I have authentication issue.
  I can't find how to apply security successfully on my cluster. Unable to set password or unable to authenticate ?</p>