code: protected void startServing(String startMessage, String stopMessage) {
      MetricsSystem.startSinks(ServerConfiguration.get(PropertyKey.METRICS_CONF_FILE));
      startServingWebServer();
      startJvmMonitorProcess();
      LOG.info(
          "Alluxio master version {} started{}. bindAddress={}, connectAddress={}, webAddress={}",
          RuntimeConstants.VERSION, startMessage, mRpcBindAddress, mRpcConnectAddress,
          mWebBindAddress);
      startServingRPCServer();
      LOG.info("Alluxio master ended{}", stopMessage);
    }
docs: Starts serving, letting {@link MetricsSystem} start sink and starting the web ui server and RPC
  Server.
  
  @param startMessage empty string or the message that the master gains the leadership
  @param stopMessage empty string or the message that the master loses the leadership