protected Cluster getCluster() throws AmbariException {
    Cluster cluster = clusters.getCluster(getClusterName());

    if (cluster == null) {
      throw new AmbariException(String.format("Failed to retrieve cluster for %s", getClusterName()));
    }

    return cluster;
  }
Returns the relevant Cluster object

@return the relevant Cluster
@throws AmbariException if the Cluster object cannot be retrieved
ambari-server/src/main/java/org/apache/ambari/server/serveraction/kerberos/KerberosServerAction.java