参考：
笔记
https://www.cnblogs.com/yinzhengjie/p/11183988.html
官网：
http://flume.apache.org/documentation.html
user guide:
https://github.com/apache/flume/blob/trunk/flume-ng-doc/sphinx/FlumeUserGuide.rst
原文：https://www.cnblogs.com/hongfeng2019/p/11988507.html