@VisibleForTesting
  Map<String, String> getContainerEnvironment(Configuration conf, boolean isMap) {
    Map<String, String> environment = new HashMap<String, String>();
    MRHelpers.updateEnvBasedOnMRTaskEnv(conf, environment, isMap);
    return environment;
  }
Utility method to create a stripped down configuration for the MR partitioner.

@param partitionerClassName
         the real MR partitioner class name
@param baseConf
         a base configuration to extract relevant properties
@return
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/DagUtils.java