Ranger-Admin enable security mode should not depend on configuration logdir,
in fact, it should depend on whether hadoop.security.authentication is kerberos.
If the logdir is null, even if Ranger-Admin is set to Kerberos authentication,
the Ranger-Admin would not enable security mode.
By the way, people who read the code will be confused,
because logdir has nothing to do with security of Ranger-Admin.
The code which have problem can be found in Java method EmbeddedServer.start():