One of the advantages about using DevOps practices is that you can rely less in documentation and more on orchestration. Documentation can come from a vendor or the engineer that configured the system or a mix of both since you have to modify based on your environments. Using an Ansible role like the one developed by Elastic saves a ton of time and add best practices and performance tuning while at it!
The Ansible Role
Here is the link to the role: it is developed by Elastic Search so it has great documentation.