失败的地图任务超出允许限制

Question

我正在尝试使用Python进行Hadoop流式传输。我已经通过here

的帮助编写了简单的地图并减少了脚本

map脚本如下：

#!/usr/bin/env python

import sys, urllib, re

title_re = re.compile("<title>(.*?)</title>", re.MULTILINE | re.DOTALL | re.IGNORECASE)

for line in sys.stdin:
    url = line.strip()
    match = title_re.search(urllib.urlopen(url).read())
    if match :
        print url, "\t", match.group(1).strip()

和reduce脚本如下：

#!/usr/bin/env python

from operator import itemgetter
import sys

for line in sys.stdin :
    line = line.strip()
    print line

使用hadoop流式jar运行这些脚本后，map任务完成，我可以看到它们已完成100％，但reduce工作停留在22％，经过很长一段时间后，它给出了ERROR streaming.StreamJob: Job not successful. Error: # of failed Map Tasks exceeded allowed limit. FailedCount: 1.错误。

我无法找到背后的确切原因。

我的终端窗口如下所示：

shekhar@ubuntu:/host/Shekhar/Softwares/hadoop-1.0.0$ hadoop jar contrib/streaming/hadoop-streaming-1.0.0.jar -mapper /host/Shekhar/HadoopWorld/MultiFetch.py -reducer /host/Shekhar/HadoopWorld/reducer.py -input /host/Shekhar/HadoopWorld/urls/* -output /host/Shekhar/HadoopWorld/titles3
Warning: $HADOOP_HOME is deprecated.

packageJobJar: [/tmp/hadoop-shekhar/hadoop-unjar2709939812732871143/] [] /tmp/streamjob1176812134999992997.jar tmpDir=null
12/05/27 11:27:46 INFO util.NativeCodeLoader: Loaded the native-hadoop library
12/05/27 11:27:46 INFO mapred.FileInputFormat: Total input paths to process : 3
12/05/27 11:27:46 INFO streaming.StreamJob: getLocalDirs(): [/tmp/hadoop-shekhar/mapred/local]
12/05/27 11:27:46 INFO streaming.StreamJob: Running job: job_201205271050_0006
12/05/27 11:27:46 INFO streaming.StreamJob: To kill this job, run:
12/05/27 11:27:46 INFO streaming.StreamJob: /host/Shekhar/Softwares/hadoop-1.0.0/libexec/../bin/hadoop job  -Dmapred.job.tracker=localhost:9001 -kill job_201205271050_0006
12/05/27 11:27:46 INFO streaming.StreamJob: Tracking URL: http://localhost:50030/jobdetails.jsp?jobid=job_201205271050_0006
12/05/27 11:27:47 INFO streaming.StreamJob:  map 0%  reduce 0%
12/05/27 11:28:07 INFO streaming.StreamJob:  map 67%  reduce 0%
12/05/27 11:28:37 INFO streaming.StreamJob:  map 100%  reduce 0%
12/05/27 11:28:40 INFO streaming.StreamJob:  map 100%  reduce 11%
12/05/27 11:28:49 INFO streaming.StreamJob:  map 100%  reduce 22%
12/05/27 11:31:35 INFO streaming.StreamJob:  map 67%  reduce 22%
12/05/27 11:31:44 INFO streaming.StreamJob:  map 100%  reduce 22%
12/05/27 11:34:52 INFO streaming.StreamJob:  map 67%  reduce 22%
12/05/27 11:35:01 INFO streaming.StreamJob:  map 100%  reduce 22%
12/05/27 11:38:11 INFO streaming.StreamJob:  map 67%  reduce 22%
12/05/27 11:38:20 INFO streaming.StreamJob:  map 100%  reduce 22%
12/05/27 11:41:29 INFO streaming.StreamJob:  map 67%  reduce 22%
12/05/27 11:41:35 INFO streaming.StreamJob:  map 100%  reduce 100%
12/05/27 11:41:35 INFO streaming.StreamJob: To kill this job, run:
12/05/27 11:41:35 INFO streaming.StreamJob: /host/Shekhar/Softwares/hadoop-1.0.0/libexec/../bin/hadoop job  -Dmapred.job.tracker=localhost:9001 -kill job_201205271050_0006
12/05/27 11:41:35 INFO streaming.StreamJob: Tracking URL: http://localhost:50030/jobdetails.jsp?jobid=job_201205271050_0006
12/05/27 11:41:35 ERROR streaming.StreamJob: Job not successful. Error: # of failed Map Tasks exceeded allowed limit. FailedCount: 1. LastFailedTask: task_201205271050_0006_m_000001
12/05/27 11:41:35 INFO streaming.StreamJob: killJob...
Streaming Job Failed!

任何人都可以帮助我吗？

修改工作追踪细节如下：

Hadoop job_201205271050_0006 on localhost

User: shekhar
Job Name: streamjob1176812134999992997.jar
Job File: file:/tmp/hadoop-shekhar/mapred/staging/shekhar/.staging/job_201205271050_0006/job.xml
Submit Host: ubuntu
Submit Host Address: 127.0.1.1
Job-ACLs: All users are allowed
Job Setup: Successful
Status: Failed
Failure Info:# of failed Map Tasks exceeded allowed limit. FailedCount: 1. LastFailedTask: task_201205271050_0006_m_000001
Started at: Sun May 27 11:27:46 IST 2012
Failed at: Sun May 27 11:41:35 IST 2012
Failed in: 13mins, 48sec
Job Cleanup: Successful
Black-listed TaskTrackers: 1
Kind    % Complete  Num Tasks   Pending Running Complete    Killed  Failed/Killed
Task Attempts
map 100.00%
3   0   0   2   1   4 / 0
reduce  100.00%
1   0   0   0   1   0 / 1

Answer 1

此错误只是一般错误，太多Map任务未能完成：

失败的地图任务超出允许限制

您可以使用EMR控制台导航到各个Map / Reduce任务的日志。然后你应该能够看到问题所在。

在我的情况下 - 当我犯了一些小错误时，我得到了这个错误，比如错误地设置了Map脚本的路径。

查看任务日志的步骤：

http://antipatterns.blogspot.nl/2013/03/amazon-emr-map-reduce-error-of-failed.html

Answer 2

我刚出现同样的错误。在我的情况下，它结果是一个解析错误。在stdin拆分线的地方有一条“意外”的新线。我建议检查你的数据文件。一旦我删除了具有这些新行的列，它就可以正常工作。

Answer 3

首先检查你的stderr。您的信息不足以确定它是什么错误，stderr通常在： {your hadoop temp dir here} / mapred / local / userlogs / {your job id} / {your attempt id} / stderr

Sean的答案是你第一次使用hadoop的情况，所以我猜你可能会得到'env：python \ r：没有这样的文件或目录'错误。如果是这样，只需将CR替换为LF即可解决此问题。只需运行一个脚本，用\ n

替换\ r \ n

Answer 4

在Mapper和Reducer的开头添加以下行：

#!/usr/bin/python

失败的Map任务数超出允许限制

4 个答案:

失败的地图任务超出允许限制