code: public static void setupSecondarySort(Configuration conf) {
          ShuffleUtils.configBuilder()
                  .useNewApi()
                  .setPartitionerIndices(TupleFields.LAST_NAME)
                  .setSortIndices(TupleFields.values())
                  .setGroupIndices(TupleFields.LAST_NAME)
                  .configure(conf);
      }
docs: Partition and group on just the last name; sort on both last and first name.
  
  @param conf the Hadoop config