code: void start() {
      // if health script path is not configured don't start the thread.
      if (!shouldRun(conf)) {
        LOG.info("Not starting node health monitor");
        return;
      }
      nodeHealthScriptScheduler = new Timer("NodeHealthMonitor-Timer", true);
      // Start the timer task immediately and
      // then periodically at interval time.
      nodeHealthScriptScheduler.scheduleAtFixedRate(timer, 0, intervalTime);
    }
docs: Method used to start the Node health monitoring.