code: public static void main(String[] args) {
      if (args.length != 0) {
        LOG.warn("java -cp {} {}", RuntimeConstants.ALLUXIO_JAR,
            AlluxioMasterMonitor.class.getCanonicalName());
        LOG.warn("ignoring arguments");
      }
  
      AlluxioConfiguration alluxioConf = new InstancedConfiguration(ConfigurationUtils.defaults());
  
      MasterHealthCheckClient.Builder builder = new MasterHealthCheckClient.Builder(alluxioConf);
      if (ConfigurationUtils.isHaMode(alluxioConf)) {
        builder.withProcessCheck(true);
      } else {
        builder.withProcessCheck(false);
      }
      HealthCheckClient client = builder.build();
      if (!client.isServing()) {
        System.exit(1);
      }
      System.exit(0);
    }
docs: Starts the Alluxio master monitor.
  
  @param args command line arguments, should be empty