一、现象

ssh 登入到远程机器执行zkServer.sh start失败，但是手动执行确是可以执行成功的

二、定位错位日志

• 查看日志发现

[hadoop@hadoop001 logs]$ cat zookeeper.log 
nohup: failed to run command ‘java’: No such file or directory

三、分析错误

[hadoop@hadoop001 logs]$ ssh hadoop001 "which java"                           
which: no java in (/usr/local/bin:/usr/bin)
[hadoop@hadoop001 logs]$ ssh hadoop001 "echo ${JAVA_HOME}"
/usr/java/jdk1.8.0_45
[hadoop@hadoop001 logs]$ ssh hadoop001 "echo ${PATH}"     
/home/hadoop/app/hadoop/bin:/home/hadoop/app/hadoop/sbin:/home/hadoop/app/zookeeper/bin:/usr/java/jdk1.8.0_45/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin
[hadoop@hadoop001 logs]$ which java
/usr/java/jdk1.8.0_45/bin/java

发现ssh hadoop001 "which java"找不到java
但是ssh hadoop001 "echo ${JAVA_HOME}"打印可以找到java
本地也是安装配置了java的

四、查找zkServer.sh

#zkServer.sh start|stop|status
case $1 in
start)
    echo  -n "Starting zookeeper ... "
    if [ -f "$ZOOPIDFILE" ]; then
      if kill -0 `cat "$ZOOPIDFILE"` > /dev/null 2>&1; then
         echo $command already running as process `cat "$ZOOPIDFILE"`.
         exit 0
      fi
    fi

#后台开启zookeeper服务
nohup "$JAVA" "-Dzookeeper.log.dir=${ZOO_LOG_DIR}" "-Dzookeeper.root.logger=${ZOO_LOG4J_PROP}" \
    -cp "$CLASSPATH" $JVMFLAGS $ZOOMAIN "$ZOOCFG" > "$_ZOO_DAEMON_OUT" 2>&1 < /dev/null &

但是全局搜索找不到$JAVA,应该是从其他脚本引入过来的，经过定位是从zkEnv.sh过来的

# . 代表执行zkEnv.sh
if [ -e "$ZOOBIN/../libexec/zkEnv.sh" ]; then
  . "$ZOOBINDIR/../libexec/zkEnv.sh"
else
  . "$ZOOBINDIR/zkEnv.sh"
fi

五、查找zkEnv.sh

if [ "$JAVA_HOME" != "" ]; then
  JAVA="$JAVA_HOME/bin/java"
else
  JAVA=java
fi

找到$JAVA位置，这时候我们可以测试下$JAVA_HOME是否为空
发现$JAVA_HOME为空

六、解决方案

• 写死路径

if [ "$JAVA_HOME" != "" ]; then
 JAVA="$JAVA_HOME/bin/java"
else
 JAVA=/usr/java/jdk1.8.0_45/bin/java
fi

• vi ~/.bashrc 添加java环境变量
  ssh执行远程命令和脚本
  bash模式: 加载环境变量配置文件: 个人.bashrc
  所以当我们ssh时，加载的是远程用户的.bashrc文件

[hadoop@hadoop001 ~]$ vi .bashrc 
export JAVA_HOME=/usr/java/jdk1.8.0_45
export PATH=$JAVA_HOME/bin:$PATH
[hadoop@hadoop001 ~]$ source .bashrc