cluster.addConfig(config);
cluster.addDesiredConfig("_test", config);
clusters.mapHostsToCluster(hostNames, clusterName);
Service hdfs = cluster.addService(serviceName);
hdfs.persist();
hdfs.addServiceComponent(Role.DATANODE.name()).persist();
hdfs.getServiceComponent(Role.DATANODE.name()).addServiceComponentHost
(hostname1).persist();
hdfs.addServiceComponent(Role.NAMENODE.name()).persist();