https://www.elastic.co/guide/en/x-pack/current/setting-up-authentication.html
https://www.elastic.co/guide/en/x-pack/current/active-directory-realm.html
X-Pack for the Elastic Stack [6.2] » Securing the Elastic Stack »Setting Up User Authentication
原文：https://www.cnblogs.com/chucklu/p/10570121.html
