Kerberos has a reputation for being complex. I would try to first get the pure TinkerPop example working, using the TInkerPop Gremlin-server and Gremlin Console distributions. Also check the log output of Gremlin Server in case of exceptions in Gremlin Console. The command graph = JanusGraphFactory.open('') is not the best example to start with in Gremlin Console. Better is g.V().limit(5).