@Override
    public void run() {
      try {
        LOG.info("Hook closing fs=" + this.fs);
        this.fs.close();
      } catch (IOException e) {
        LOG.warn("Running hook", e);
      }
    }
Alternate shutdown hook. Just shuts down the passed fs, not all as default filesystem hook
does.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/MiniHBaseCluster.java