anchor.diff:      enabled: true
   ...
   ----
  -If we do that, all Elasticsearch nodes will be stopped at the same time, making the whole cluster unavailable.
  +
  +This naive Ansible playbook will stop all Elasticsearch nodes at the same time, making the whole cluster unavailable until nodes are started again.
   To fix this problem, the role can be ran in serial instead of parallel:
   
   .deploy.yml
  
positive.code: Then on lucky days, you can skip the expensive `stop_start` step and have a quick and fully parallel deployment.
  
  Other days, when upgrading nodes version, or changing configuration which can not be hot reloaded, running the Ansible playbook will be slower.
  Node specific configuration (`elasticsearch.yml`, Kafka `server.properties`...) is usually part of the problem as it required node restart.
  
  .playbook.yml
  [source,yaml]
  
negative.code: Let's take the Elasticsearch example.
  
  The tasks required to deploy Elasticsearch on each host of the cluster are gathered in an `elasticsearch` role.
  In short, a role is a recipe to install and update an Elasticsearch node.
  Once declared, this role is applied to all hosts belonging to the `elasticsearch` group in the Ansible playbook.
  
  .playbook.yml
  