You are mixing up two procedures:
- Gremlin Server Krb5Authenticator is for authenticating gremlin clients towards Gremlin Server. Apparently, you do not want it, so remove it from your configs.
- Apparently you are trying to have Gremlin Server authenticate againts HBase. This has nothing to do with Gremlin Server's Krb5Authenticate. If the keytab for Gremlin Server is OK and a kinit was done on the Gremlin Server host with the right user, the hbase client of janusgraph-hbase, running on the Gremlin Server host, should be able to access the TGT and authenticate to HBase.
Best wishes, Marc