It is recommended that you store audits in both HDFS and Solr, so you should install Apache Solr.

To ensure that LDAP/AD group level authorization is enforced in Hadoop, you should set up Hadoop group mapping for LDAP.

A MySQL, Oracle, or PostgreSQL database instance must be running and available to be used by Ranger.

The Ranger installation will create two new users (default names: rangeradmin and rangerlogger) and two new databases (default names: ranger and ranger_audit).

Configuration of the database instance for Ranger is described in the following sections for some of the databases supported by Ranger.

If you choose not to provide system Database Administrator (DBA) account details to the Ambari Ranger installer, you can use the dba_script.py Python script to create Ranger DB database users without exposing DBA account information to the Ambari Ranger installer. You can then run the normal Ambari Ranger installation without specifying a DBA user name and password. For more information see Setting up Database Users Without Sharing DBA Credentials.