使用root配置的hadoop启动时报错

一、报错信息：

　　Starting namenodes on [master]

        ERROR: Attempting to operate on hdfs namenode as root
        
        ERROR: but there is no HDFS_NAMENODE_USER defined. Aborting operation.
        
        Starting datanodes

        ERROR: Attempting to operate on hdfs datanode as root
        
        ERROR: but there is no HDFS_DATANODE_USER defined. Aborting operation.

        Starting secondary namenodes [slave1]

        ERROR: Attempting to operate on hdfs secondarynamenode as root

        ERROR: but there is no HDFS_SECONDARYNAMENODE_USER defined. Aborting operation.

二、解决办法

在/hadoop/sbin路径下： 

将 start-dfs.sh，stop-dfs.sh两个文件顶部添加以下参数

HDFS_DATANODE_U