啟動yarn的報錯JAVA_HOME not set的處理辦法

問題： JAVA_HOME is not set

解決辦法：

新增兩處：

1.$HADOOP_HOME/etc/hadoop/yarn-env.sh 

中新增：

--------------------------------上面新增------

export JAVA_HOME=/usr/java/jdk1.7.0_55 

if [ "$JAVA_HOME" != "" ]; then
  #echo "run java in $JAVA_HOME"
  JAVA_HOME=$JAVA_HOME
fi
  
if [ "$JAVA_HOME" = "" ]; then
  echo "Error: JAVA_HOME is not set."
  exit 1
fi

--------------------------------------------------------------------

export JAVA_HOME=/usr/java/jdk1.7.0_55   (根據自己jdk 的路徑來設定)

2. $HADOOP_HOME/libexec/hadoop-config.sh

 ----------------------------下面新增：

# Newer versions of glibc use an arena memory allocator that causes virtual
# memory usage to explode. This interacts badly with the many threads that
# we use in Hadoop. Tune the variable down to prevent vmem explosion.

export JAVA_HOME=/usr/java/jdk1.7.0_55

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