一炒事、錯(cuò)誤: 找不到或無法加載主類 org.apache.hadoop.mapreduce.v2.app.MRAppMaster
錯(cuò)誤信息:
Container exited with a non-zero exit code 1. Error file: prelaunch.err.
Last 4096 bytes of prelaunch.err :
Last 4096 bytes of stderr :
錯(cuò)誤: 找不到或無法加載主類 org.apache.hadoop.mapreduce.v2.app.MRAppMaster
解決方法:
在主機(jī)中運(yùn)行:hadoop classpath
記下返回的結(jié)果
vi $HADOOP_HOME/etc/hadoop/yarn-site.xml
添加一個(gè)配置
<property>
<name>yarn.application.classpath</name>
<value>hadoop classpath返回信息</value>
</property>
二、Hadoop格式化后start.all.sh運(yùn)行出錯(cuò)
1穴亏、master，slave都需要修改start-dfs.sh，stop-dfs.sh迫肖，start-yarn.sh锅劝，stop-yarn.sh四個(gè)文件
2、如果你的Hadoop是另外啟用其它用戶來啟動(dòng)蟆湖，記得將root改為對(duì)應(yīng)用戶
HDFS格式化后啟動(dòng)dfs出現(xiàn)以下錯(cuò)誤：
[root@hadoop101 hadoop-3.2.0]# sbin/start-all.sh
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.
在/hadoop/sbin路徑下：
將start-dfs.sh，stop-dfs.sh兩個(gè)文件頂部添加以下參數(shù)
#!/usr/bin/env bash
HDFS_DATANODE_USER=root
HDFS_DATANODE_SECURE_USER=hdfs
HDFS_NAMENODE_USER=root
HDFS_SECONDARYNAMENODE_USER=root
還有玻粪，start-yarn.sh隅津，stop-yarn.sh頂部也需添加以下：
#!/usr/bin/env bash
YARN_RESOURCEMANAGER_USER=root
HADOOP_SECURE_DN_USER=yarn
YARN_NODEMANAGER_USER=root
修改后重啟 ./start-all.sh，成功劲室！
[root@master sbin]# ./start-dfs.sh
WARNING: HADOOP_SECURE_DN_USER has been replaced by HDFS_DATANODE_SECURE_USER. Using value of HADOOP_SECURE_DN_USER.
Starting namenodes on [master]
上一次登錄：日 6月 3 03:01:37 CST 2018從 slave1pts/2 上
master: Warning: Permanently added 'master,192.168.43.161' (ECDSA) to the list of known hosts.
Starting datanodes
上一次登錄：日 6月 3 04:09:05 CST 2018pts/1 上
Starting secondary namenodes [slave1]
上一次登錄：日 6月 3 04:09:08 CST 2018pts/1 上
