hadoop配置文件之yarn-env.sh

# User for YARN daemons
# yarn 守护进程用户
export HADOOP_YARN_USER=${HADOOP_YARN_USER:-yarn}

# resolve links - $0 may be a softlink
# yarn配置文件地址
export YARN_CONF_DIR="${YARN_CONF_DIR:-$HADOOP_YARN_HOME/conf}"

# some Java parameters
#JAVA_HOME 路径
export JAVA_HOME=/home/y/libexec/jdk1.6.0/
#如果已经配置JAVA_HOME就使用已经配置的JAVA_HOME，如果没配置就退出
if [ "$JAVA_HOME" != "" ]; then
  #echo "run java in $JAVA_HOME"
  JAVA_HOME=$JAVA_HOME
fi
if [ "$JAVA_HOME" = "" ]; then
  echo "Error: JAVA_HOME is not set."
  exit 1
fi
#避免只配置了JAVA_HOME没有配置JAVA_HOME/bin到PATH
JAVA=$JAVA_HOME/bin/java

#yarn的最大内存
JAVA_HEAP_MAX=-Xmx1000m 

# For setting YARN specific HEAP sizes please use this
# Parameter and set appropriately
# 如果设置了YARN_HEAPSIZE上面配置的JAVA_HEAP_MAX将会被覆盖
YARN_HEAPSIZE=1000
# check envvars which might override default args
if [ "$YARN_HEAPSIZE" != "" ]; then
  JAVA_HEAP_MAX="-Xmx""$YARN_HEAPSIZE""m"
fi