WARNING : That documentation was written for an old version of Ranger. Some of the options changed in the latest versions of Ranger (for e.g. Anonymous bind isn't supported anymore).
As you may want to create policies using the user groups defined in a LDAP, you have to synchronize Ranger to your LDAP. This will be done using UserSync, a component of Ranger designed to synchronize users from Unix or from LDAP.
...