UserGroupInformation and Kerberos

[Jorge Machado]

Hey everyone, I was working with UserGroupInformation Class and Kerberos.

 Is there a proper example how to renew the Kerkebros Ticket from a keytab ? 

For Example: 

assuming that  I have the jaas.config set in the jvm I do: 

        UserGroupInformation loginUser = UserGroupInformation.getLoginUser();
        This will login the user but not using a keytab. 

        Using this code it will login with Kerberos: 
                UserGroupInformation.setConfiguration(conf);
                Krb5LoginModule context = new Krb5LoginModule();
                Subject subject = new Subject();
                javax.security.auth.login.Configuration jconf = 
javax.security.auth.login.Configuration.getConfiguration();
                AppConfigurationEntry entries[] = 
jconf.getAppConfigurationEntry("Client");
                context.initialize(subject,null, new HashMap<String, 
String>(),entries[0].getOptions());
                context.login();
                context.commit();
                UserGroupInformation.loginUserFromSubject(subject);


How Do I make sure that my Keytab get’s renewed ? I think Hadoop Libraries 
should take of this. I can count  a lot of projects implementing their own 
TicketRewener… 

Any suggestions here ? 

Thanks


Jorge Machado