private boolean hasSameKeytab(KerberosIdentityDescriptor that) {
    try {
      return this.getKeytabDescriptor().getFile().equals(that.getKeytabDescriptor().getFile());
    } catch (NullPointerException e) {
      return false;
    }
  }
@return true if the given identity has the same principal or keytab as me
ambari-server/src/main/java/org/apache/ambari/server/state/kerberos/KerberosIdentityDescriptor.java