code: private void showAdminFormLocalityDelay(PrintWriter out, boolean advancedView) {
      out.print("<h2>Locality Delay</h2>\n");
      String advParam = advancedView ? "&advanced" : "";
      long localityDelayRackLocal = scheduler.getLocalityDelayRackLocal();
      long localityDelayNodeLocal = scheduler.getLocalityDelayNodeLocal();
      Collection<String> possibleDelay = Arrays.asList(
        ("0,1000,2000,3000,4000,5000,10000,15000,20000,25000,30000").split(","));
      out.printf("<p>Mapper NODE locality delay = <b>%s milliseconds</b>.",
          generateSelect(possibleDelay, "" + localityDelayNodeLocal,
              "/fairscheduler?setLocalityDelayNodeLocal=<CHOICE>" + advParam));
      out.printf("<p>Mapper RACK locality delay = <b>%s milliseconds</b>.",
          generateSelect(possibleDelay, "" + localityDelayRackLocal,
              "/fairscheduler?setLocalityDelayRackLocal=<CHOICE>" + advParam));
    }
docs: Print the administration form at the bottom of the page, which currently
  only includes the button for switching between FIFO and Fair Scheduling.