hadoop，python，子进程失败，代码为127 [英] hadoop, python, subprocess failed with code 127

问题描述

我正在尝试使用mapreduce运行非常简单的任务.

I'm trying to run very simple task with mapreduce.

mapper.py:

mapper.py:

#!/usr/bin/env python
import sys
for line in sys.stdin:
    print line

我的txt文件:

qwerty
asdfgh
zxc

运行作业的命令行:

hadoop jar /usr/lib/hadoop-0.20-mapreduce/contrib/streaming/hadoop-streaming-2.6.0-mr1-cdh5.8.0.jar \
-input /user/cloudera/In/test.txt \
-output /user/cloudera/test \
-mapper /home/cloudera/Documents/map.py \
-file /home/cloudera/Documents/map.py

错误:

INFO mapreduce.Job: Task Id : attempt_1490617885665_0008_m_000001_0, Status : FAILED
Error: java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 127
    at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:325)
    at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:538)
    at org.apache.hadoop.streaming.PipeMapper.close(PipeMapper.java:130)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:61)
    at org.apache.hadoop.streaming.PipeMapRunner.run(PipeMapRunner.java:34)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1693)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)

如何解决此问题并运行代码? 当我使用cat /home/cloudera/Documents/test.txt | python /home/cloudera/Documents/map.py时，效果很好

How to fix this and run the code? When I use cat /home/cloudera/Documents/test.txt | python /home/cloudera/Documents/map.py it works fine

!!!!! UPDATE

我的* .py文件出了点​​问题.我已经从github'tom white hadoop book'复制了文件，并且一切正常.

Something wrong with my *.py file. I have copied file from github 'tom white hadoop book' and everything is working fine.

但是我不明白是什么原因.它不是权限和字符集(如果我没记错的话).还有什么呢?

But I cant understand what is the reason. It is not the permissions and charset (if I am not wrong). What else can it be?

推荐答案

我遇到了同样的问题.

问题: 在Windows环境中创建python文件时，新的换行符为 CRLF . 我的hadoop在Linux上运行，该Linux将换行符理解为 LF

Issue: When the python file is created in Windows environment the new line character is CRLF. My hadoop runs on Linux which understands the newline character as LF

解决方案: 将 CRLF 更改为 LF 后，该步骤成功运行.

Solution: After changing the CRLF to LF the step ran successfully.

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