今天重新搭建了一个3节点的Hadoop集群,想着在上面测试一个MapReduce实例,然后就出现了以下错误:
[hadoop@master hadoop-2.6.0]$ hadoop
-bash: hadoop: command not found
出现这个错误的原因是没有配置环境变量,操作过程如下。
vi /etc/profile //权限不够时再前面加上sudo
进入配置文件后,按照以下配置进行对比,没有的请写进去。
#hadoop
export HADOOP_HOME=/opt/modules/hadoop-2.6.0
#java
export JAVA_HOME=/opt/modules/jdk
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin:$HADOOP_HOME/bin
配置完成后执行下列命令更新配置
source /etc/profile
然后运行hadoop命令查看配置是否生效,内容如下。
[hadoop@master hadoop-2.6.0]$ hadoop
Usage: hadoop [--config confdir] COMMAND
where COMMAND is one of:
fs run a generic filesystem user client
version print the version
jar <jar> run a jar file
checknative [-a|-h] check native hadoop and compression libraries availability
distcp <srcurl> <desturl> copy file or directories recursively
archive -archiveName NAME -p <parent path> <src>* <dest> create a hadoop archive
classpath prints the class path needed to get the
credential interact with credential providers
Hadoop jar and the required libraries
daemonlog get/set the log level for each daemon
trace view and modify Hadoop tracing settings
or
CLASSNAME run the class named CLASSNAME
Most commands print help when invoked w/o parameters.
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