Want to know more about Ranger and how it can be used to protect the Hadoop Eco system, then look no further. This is a blog that provides a overview of Ranger along with its architecture. This also provides link to the video of how to install and configure Ranger in IOP 4.2.
Ranger supports three Authentication methods namely : Active Directory, LDAP and Unix. But it used to support only shadow based authentication if configured for Unix authentication. That was outdated as recent Linux systems now support PAM authentication which allows multiple authentication sources and also does authorization.