public MiniTezShim(Configuration conf, int numberOfTaskTrackers, String nameNode)
     throws IOException {
   mr = new MiniTezCluster("hive", numberOfTaskTrackers);
   conf.set("fs.defaultFS", nameNode);
   conf.set("tez.am.log.level", "DEBUG");
   conf.set(MRJobConfig.MR_AM_STAGING_DIR, "/apps_staging_dir");
   mr.init(conf);
   mr.start();
   this.conf = mr.getConfig();
 }