Datastax Java Driver with kerberos security

Question

Am trying to access kerberos enabled DSE cluster from eclipse.

Sample connection code is

public void connect(String node) {
  cluster = Cluster.builder().addContactPoint(node)
    .withAuthProvider(new DseAuthProvider()).build();
  Metadata metadata = cluster.getMetadata();
  Iterator<KeyspaceMetadata> in = metadata.getKeyspaces().iterator();
  while (in.hasNext()) {
   // System.out.println("Keyspaces");
   System.out.println(in.next().getName());
  }

My dseclient file looks like this

  DseClient {
        com.sun.security.auth.module.Krb5LoginModule required
          useKeyTab=true
          keyTab="/path/to/file.keytab"
          principal="user@MYDOMAIN.COM";
    };

Am getting the below exception when I run the code

Exception in thread "main" java.lang.RuntimeException: javax.security.auth.login.LoginException: Cannot locate default realm
 at com.datastax.driver.core.sasl.KerberosAuthenticator.loginSubject(KerberosAuthenticator.java:113)
 at com.datastax.driver.core.sasl.KerberosAuthenticator.<init>(KerberosAuthenticator.java:94)
 at com.datastax.driver.core.sasl.DseAuthProvider.newAuthenticator(DseAuthProvider.java:52)
 at com.datastax.driver.core.Connection.initializeTransport(Connection.java:164)
 at com.datastax.driver.core.Connection.<init>(Connection.java:132)
 at com.datastax.driver.core.Connection.<init>(Connection.java:59)
 at com.datastax.driver.core.Connection$Factory.open(Connection.java:442)
 at com.datastax.driver.core.ControlConnection.tryConnect(ControlConnection.java:205)
 at com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:168)
 at com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:81)
 at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:662)
 at com.datastax.driver.core.Cluster$Manager.access$100(Cluster.java:604)
 at com.datastax.driver.core.Cluster.<init>(Cluster.java:69)
 at com.datastax.driver.core.Cluster.buildFrom(Cluster.java:96)
 at com.datastax.driver.core.Cluster$Builder.build(Cluster.java:585)
 at AuthenticatedClient.connect(AuthenticatedClient.java:19)
 at AuthenticatedClient.main(AuthenticatedClient.java:59)
Caused by: javax.security.auth.login.LoginException: Cannot locate default realm
 at com.sun.security.auth.module.Krb5LoginModule.attemptAuthentication(Unknown Source)
 at com.sun.security.auth.module.Krb5LoginModule.login(Unknown Source)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 at java.lang.reflect.Method.invoke(Unknown Source)
 at javax.security.auth.login.LoginContext.invoke(Unknown Source)
 at javax.security.auth.login.LoginContext.access$000(Unknown Source)
 at javax.security.auth.login.LoginContext$4.run(Unknown Source)
 at javax.security.auth.login.LoginContext$4.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at javax.security.auth.login.LoginContext.invokePriv(Unknown Source)
 at javax.security.auth.login.LoginContext.login(Unknown Source)
 at com.datastax.driver.core.sasl.KerberosAuthenticator.loginSubject(KerberosAuthenticator.java:109)
 ... 16 more
Caused by: KrbException: Cannot locate default realm
 at sun.security.krb5.PrincipalName.<init>(Unknown Source)
 at sun.security.krb5.KrbAsReq.<init>(Unknown Source)
 at sun.security.krb5.KrbAsReqBuilder.build(Unknown Source)
 at sun.security.krb5.KrbAsReqBuilder.send(Unknown Source)
 at sun.security.krb5.KrbAsReqBuilder.action(Unknown Source)
 ... 30 more
Caused by: KrbException: Cannot locate default realm
 at sun.security.krb5.Config.getDefaultRealm(Unknown Source)
 ... 35 more
Caused by: KrbException: Generic error (description in e-text) (60) - Unable to locate Kerberos realm
 at sun.security.krb5.Config.getRealmFromDNS(Unknown Source)
 ... 36 more

Am using DSE 3.2.3 and java driver 1.0.4

Answer 1

Most likely, this points to a missing or misconfigured Kerberos setup on the client. On linux, the relevant file is /etc/krb5.conf and you may want to check the [libdefaults] and [realms] sections. For the JAAS config you're using, I'd expect to see something like this in your krb5.conf:

[libdefaults]
default_realm = MYDOMAIN.COM
.
.
.
[realms]
MYDOMAIN.COM = {
    kdc = <address of your kdc>
    admin_server = <address of the domain admin server>
}

You'll also want to ensure that DNS name resolution is properly setup. From the client machine, make sure both forward and backward resolution are working correctly e.g.:

nslookup <hostname> && nslookup <host ip>

I would also validate that you can connect to the cluster using cqlsh, following the instructions here: http://www.datastax.com/docs/datastax_enterprise3.2/security/cqlsh_setup#security-run-cqlsh

If you're running OSX on the client machine, this bug might also be relevant to you : http://bugs.java.com/bugdatabase/view_bug.do?bug_id=7184815