Hadoop之—— CentOS Warning: $HADOOP

Hadoop之—— CentOS Warning: $HADOOP_HOME is deprecated解

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启动Hadoop时报了一个警告信息。我安装的Hadoop版本号是hadoop1.0.4，详细警告信息例如以下：

[root@localhost hadoop-1.0.4]# ./bin/start-all.sh
Warning: $HADOOP_HOME is deprecated.

网上的说法是由于Hadoop本身对HADOOP_HOME做了推断。详细在bin/hadoop和bin/hadoop-config.sh里。在hadoop-config.sh里有例如以下的配置：

if [ "$HADOOP_HOME_WARN_SUPPRESS" = "" ] && [ "$HADOOP_HOME" != "" ]; then
  echo "Warning: $HADOOP_HOME is deprecated." 1>&2
  echo 1>&2
fi

对于这个警告问题，解决方法例如以下：

1.凝视掉hadoop-config.sh里的上面给出的这段if fi配置（不推荐）

2.在/etc/profile里添加一个环境变量：

export HADOOP_HOME_WARN_SUPPRESS=1

注：改动完profile后须要运行source操作使其生效

source /etc/profile

备注:在ubuntu下应该是改动/home/.bashrc文件,添加一行 export HADOOP_HOME_WARN_SUPPRESS=1

运行完后我们能够检验一下配置是否成功，又一次运行start-all.sh脚本：

[root@localhost hadoop-1.0.4]# ./bin/start-all.sh 
starting namenode, logging to /root/hadoop-1.0.4/libexec/../logs/hadoop-root-namenode-localhost.out
localhost: starting datanode, logging to /root/hadoop-1.0.4/libexec/../logs/hadoop-root-datanode-localhost.out
localhost: starting secondarynamenode, logging to /root/hadoop-1.0.4/libexec/../logs/hadoop-root-secondarynamenode-localhost.out
starting jobtracker, logging to /root/hadoop-1.0.4/libexec/../logs/hadoop-root-jobtracker-localhost.out
localhost: starting tasktracker, logging to /root/hadoop-1.0.4/libexec/../logs/hadoop-root-tasktracker-localhost.out

没有出现Warning: $HADOOP_HOME is deprecated，说明问题已经解决。