Hadoop 任务超时自动结束任务

对于一些线上任务，如果在一定时间没有结束，下一时刻任务会启动，那么上一时刻的任务将变得没有意义，但是仍然会占用Hadoop资源，所以需要程序检测并自动结束。

示例：

hadoop jar /opt/hadoop/mapred/contrib/streaming/hadoop-0.21.0-streaming.jar \
  -D mapreduce.job.name="jobname" \
  -D mapreduce.job.reduces="100" \
  -D mapreduce.job.map.capacity="500" \
  -D mapreduce.job.reduce.capacity="100" \
  -mapper "$mapper"  \
  -reducer "$reducer" \
  -input "${INPUT}" \
  -output "${OUTPUT}"  \
  -file "${mapper_file}" \
  -file ${reducer_file} \
  -jobconf mapred.min.split.size=536870912 \
  -partitioner org.apache.hadoop.mapred.lib.KeyFieldBasedPartitioner 1>log 2>&1 &
PID=$!
ps_status=`ps -ef |grep $PID|grep -v grep|wc -l`
echo "$ps_status"

KILL_CMD=`sed /-Dmapreduce.jobtracker.address=${tracker_name}:${port}/p '-n' log | awk '{print $5" "$6" "$7" "$8" "$9}'`
while [ "X$KILL_CMD" = "X" ]
do
  echo "wait for kill command for a while."
  sleep 1s

   KILL_CMD=`sed /-Dmapreduce.jobtracker.address=${tracker_name}:${port}/p '-n' log | awk '{print $5" "$6" "$7" "$8" "$9}'`
done
echo $KILL_CMD

wait_time=1
while [ 1 ]
do
   ps_status=`ps -ef |grep $PID|grep -v grep|wc -l`
   if [ $ps_status -ge 1 ]; then
      echo "hadoop is running"
      wait_time=`expr $wait_time + 1`
   else
     echo "hadoop job finished."
     break
   fi 

if [ $wait_time -ge 60 ]; then       #等待5分钟，如果5分钟内任务没有结束，就结束该任务
      echo "timeout..."
      echo "[exec]$KILL_COMMAND"
      $KILL_COMMAND
      break
   fi 
   sleep 5s
done

exit 0