ERROR: but there is no HDFS_NAMENODE_USER defined. Aborting operation.
执行hadoop的start-all.sh命令式启动报如下的错误
[root@iZbp13pwlxqwiu1xxb6szsZ hadoop-3.2.1]# start-all.sh
Starting namenodes on [iZbp13pwlxqwiu1xxb6szsZ]
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 [iZbp13pwlxqwiu1xxb6szsZ]
ERROR: Attempting to operate on hdfs secondarynamenode as root
ERROR: but there is no HDFS_SECONDARYNAMENODE_USER defined. Aborting operation.
Starting resourcemanager
ERROR: Attempting to operate on yarn resourcemanager as root
ERROR: but there is no YARN_RESOURCEMANAGER_USER defined. Aborting operation.
Starting nodemanagers
ERROR: Attempting to operate on yarn nodemanager as root
ERROR: but there is no YARN_NODEMANAGER_USER defined. Aborting operation.
[root@iZbp13pwlxqwiu1xxb6szsZ hadoop-3.2.1]# 解决方法：
方法一、
在Hadoop安装目录下找到sbin文件夹
在里面修改四个文件
1、对于start-dfs.sh和stop-dfs.sh文件，添加下列参数：
#!/usr/bin/env bash
HDFS_DATANODE_USER=root
HADOOP_SECURE_DN_USER=hdfs
HDFS_NAMENODE_USER=root
HDFS_SECONDARYNAMENODE_USER=root2、对于start-yarn.sh和stop-yarn.sh文件，添加下列参数：
#!/usr/bin/env bash
YARN_RESOURCEMANAGER_USER=root
HADOOP_SECURE_DN_USER=yarn
YARN_NODEMANAGER_USER=root然后重新启动
方法二、(推荐)
The root cause of this problem,
- hadoop install for different user and you start yarn service for different user. OR
- in hadoop config's hadoop-env.sh specified HDFS_NAMENODE_USER and HDFS_DATANODE_USER user is something else.
Hence we need to correct and make it consistent at every place. So a simple solution of this problem is to edit your hadoop-env.sh file and add the user-name for which you want to start the yarn service. So go ahead and edit $HADOOP_HOME/etc/hadoop/hadoop-env.sh by adding the following lines
export HDFS_NAMENODE_USER=root
export HDFS_DATANODE_USER=root
export HDFS_SECONDARYNAMENODE_USER=root
export YARN_RESOURCEMANAGER_USER=root
export YARN_NODEMANAGER_USER=root
Now save and start yarn, hdfs service and check that it works.
我们在hadoop-env.sh文件中也可以找到如下的描述
To prevent accidents, shell commands be (superficially) locked to only allow certain users to execute certain subcommands.
为了防止发生意外，仅（部分）锁定shell命令以仅允许某些用户执行某些子命令。
It uses the format of (command)_(subcommand)_USER.For example, to limit who can execute the namenode command,export HDFS_NAMENODE_USER=hdfs
使用“命令_子命令_用户”，例如，通过使用export HDFS_NAMENODE_USER=hdfs来限制哪个用户可以执行namenode命令。
参考stackoverflow上的相关讨论
HDFS_NAMENODE_USER, HDFS_DATANODE_USER & HDFS_SECONDARYNAMENODE_USER not defined