code: public void shutdown() {
      logger.warn("Shutting down FlowRunnerManager...");
      if (this.azkabanProps.getBoolean(ConfigurationKeys.AZKABAN_POLL_MODEL, false)) {
        this.pollingService.shutdown();
      }
      this.executorService.shutdown();
      boolean result = false;
      while (!result) {
        logger.info("Awaiting Shutdown. # of executing flows: " + getNumRunningFlows());
        try {
          result = this.executorService.awaitTermination(1, TimeUnit.MINUTES);
        } catch (final InterruptedException e) {
          logger.error(e);
        }
      }
      logger.warn("Shutdown FlowRunnerManager complete.");
    }
docs: This shuts down the flow runner. The call is blocking and awaits execution of all jobs.