Amazon EMR 作业失败：因步骤失败而关闭

Question

我正在使用 Python 编写一个简单的流式映射缩减作业，以在 Amazon EMR 上运行。它基本上是用户记录的聚合器，将每个用户 ID 的条目分组在一起。

映射器

#!/usr/bin/env python
import sys

def main(argv):
line = sys.stdin.readline()
try:
    while line:
        line = line.rstrip()
        elements = line.split()
        print '%s\t%s' % (elements[0] , (elements[1],elements[2]) )
        line = sys.stdin.readline()
except "end of file":
    return None

if __name__ == '__main__':
    main(sys.argv)

减速机：

#!/usr/bin/env python
import sys

def main(argv):
users=dict()
for line in sys.stdin:
    elements=line.split('\t',1)
    if elements[0] in users:
        users[elements[0]].append(elements[1])
    else:
        users[elements[0]]=elements[1]

for user in users:
    print '%s\t%s'% ( user, users[user] )

if __name__ == '__main__':
    main(sys.argv)

此作业应在包含五个文本文件的目录上运行。 EMR作业的参数为：

输入：[桶名]/[输入文件夹名]

输出：[桶名]/输出

映射器：[桶名]/mapper.py

reducer：[桶名]/reducer.py

作业不断失败，原因是：步骤失败而关闭。这是日志的副本

2013-01-01 12:06:16,270 INFO org.apache.hadoop.mapred.JobClient (main): Default number      of map tasks: null

2013-01-01 12:06:16,271 INFO org.apache.hadoop.mapred.JobClient (main): Setting default number of map tasks based on cluster size to : 8

2013-01-01 12:06:16,271 INFO org.apache.hadoop.mapred.JobClient (main): Default number of reduce tasks: 3

2013-01-01 12:06:18,392 INFO org.apache.hadoop.security.ShellBasedUnixGroupsMapping (main): add hadoop to shell userGroupsCache

2013-01-01 12:06:18,393 INFO org.apache.hadoop.mapred.JobClient (main): Setting group to hadoop

2013-01-01 12:06:18,647 INFO com.hadoop.compression.lzo.GPLNativeCodeLoader (main): Loaded native gpl library

2013-01-01 12:06:18,670 WARN com.hadoop.compression.lzo.LzoCodec (main): Could not find build properties file with revision hash

2013-01-01 12:06:18,670 INFO com.hadoop.compression.lzo.LzoCodec (main): Successfully loaded & initialized native-lzo library [hadoop-lzo rev UNKNOWN]

2013-01-01 12:06:18,695 WARN org.apache.hadoop.io.compress.snappy.LoadSnappy (main): Snappy native library is available

2013-01-01 12:06:18,695 INFO org.apache.hadoop.io.compress.snappy.LoadSnappy (main): Snappy native library loaded

2013-01-01 12:06:19,050 INFO org.apache.hadoop.mapred.FileInputFormat (main): Total input paths to process : 5

2013-01-01 12:06:20,688 INFO org.apache.hadoop.streaming.StreamJob (main): getLocalDirs(): [/mnt/var/lib/hadoop/mapred]

2013-01-01 12:06:20,688 INFO org.apache.hadoop.streaming.StreamJob (main): Running job: job_201301011204_0001

2013-01-01 12:06:20,688 INFO org.apache.hadoop.streaming.StreamJob (main): To kill this job, run:

2013-01-01 12:06:20,688 INFO org.apache.hadoop.streaming.StreamJob (main): /home/hadoop/bin/hadoop job  -Dmapred.job.tracker=10.255.131.225:9001 -kill job_201301011204_0001

2013-01-01 12:06:20,689 INFO org.apache.hadoop.streaming.StreamJob (main): Tracking URL: http://domU-12-31-39-01-7C-13.compute-1.internal:9100/jobdetails.jsp?jobid=job_201301011204_0001

2013-01-01 12:06:21,696 INFO org.apache.hadoop.streaming.StreamJob (main):  map 0%  reduce 0%

2013-01-01 12:08:02,238 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 100%

2013-01-01 12:08:02,239 INFO org.apache.hadoop.streaming.StreamJob (main): To kill this job, run:

2013-01-01 12:08:02,240 INFO org.apache.hadoop.streaming.StreamJob (main): /home/hadoop/bin/hadoop job  -Dmapred.job.tracker=10.255.131.225:9001 -kill job_201301011204_0001

2013-01-01 12:08:02,240 INFO org.apache.hadoop.streaming.StreamJob (main): Tracking URL: http://domU-12-31-39-01-7C-13.compute-1.internal:9100/jobdetails.jsp?jobid=job_201301011204_0001

 2013-01-01 12:08:02,240 ERROR org.apache.hadoop.streaming.StreamJob (main): Job not successful. Error: # of failed Map Tasks exceeded allowed limit. FailedCount: 1. LastFailedTask: task_201301011204_0001_m_000002

 2013-01-01 12:08:02,240 INFO org.apache.hadoop.streaming.StreamJob (main): killJob...

我做错了什么？

Answer 1

解决了。确保 Python 脚本的开头没有任何 cmets，并且脚本的第一行是 #!/usr/bin/env python 行