執行hadoop的start-all.sh命令式啟動報如下的錯誤

[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]# 

解決方法：

方法一、

在Hadoop安裝目錄下找到sbin文件夾

在里面修改四個文件

1、對于start-dfs.sh和stop-dfs.sh文件，添加下列參數：

#!/usr/bin/env bash
HDFS_DATANODE_USER=root
HADOOP_SECURE_DN_USER=hdfs
HDFS_NAMENODE_USER=root
HDFS_SECONDARYNAMENODE_USER=root

2、對于start-yarn.sh和stop-yarn.sh文件，添加下列參數：

#!/usr/bin/env bash
YARN_RESOURCEMANAGER_USER=root
HADOOP_SECURE_DN_USER=yarn
YARN_NODEMANAGER_USER=root

然后重新啟動

方法二、(推薦)

The root cause of this problem,

1. hadoop install for different user and you start yarn service for different user. OR
2. 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.

我們在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.

為了防止發生意外，僅（部分）鎖定shell命令以僅允許某些用戶執行某些子命令。

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_用戶”，例如，通過使用export HDFS_NAMENODE_USER=hdfs來限制哪個用戶可以執行namenode命令。

參考stackoverflow上的相關討論

HDFS_NAMENODE_USER, HDFS_DATANODE_USER & HDFS_SECONDARYNAMENODE_USER not defined