Hadoop之HDFS概述 :https://blog.csdn.net/weixin_45102492/article/details/104369155
Hadoop之HDFS的shell操作: https://blog.csdn.net/weixin_45102492/article/details/104372580
HDFS的java客户端操作:https://blog.csdn.net/weixin_45102492/article/details/104378020
NameNode和SecondaryNameNode:https://blog.csdn.net/weixin_4