private void runInternal() throws IOException {
      Thread.currentThread().setName(getClass().getSimpleName());
      while (true) {
        scanDirs();
        try {
          Thread.sleep(500);
        } catch (InterruptedException e) {
          LOG.error("Log tailer thread interrupted", e);
          break;
        }
      }
    }
Generates a list of random port numbers in the sorted order. A sorted order makes sense if we
ever want to refer to these servers by their index in the returned array, e.g. server #0, #1,
etc.
hbase-diagnostics/src/test/java/org/apache/hadoop/hbase/util/ProcessBasedLocalHBaseCluster.java