Hadoop 2.7.x NameNode重新格式化后导致DataNode无法启动问题

简介

Hadoop 2.7.x伪分布式运行环境下，由于NameNode重新格式化后，导致DataNode无法正常启动。本文总结了此问题的解决方法和思路，供个人参考。

问题描述

通过脚本start-dfs.sh启动hadoop， 运行hadoop fs命令出现异常信息：

hadoop@bob-virtual-machine:~$ start-dfs.sh 
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop-2.7.3/logs/hadoop-hadoop-namenode-bob-virtual-machine.out
localhost: starting datanode, logging to /usr/local/hadoop-2.7.3/logs/hadoop-hadoop-datanode-bob-virtual-machine.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop-2.7.3/logs/hadoop-hadoop-secondarynamenode-bob-virtual-machine.out
hadoop@bob-virtual-machine:~$ hadoop fs -put -l /home/hadoop/hadoop-2.7.3/README.txt wordcount/README.txt
17/01/31 18:34:30 WARN hdfs.DFSClient: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /user/hadoop/wordcount/REA