python-2.7 - 无法在 python 中使用 mapreduce

Question

我正在尝试使用 python mrjob 学习 mapreduce 程序。我收到以下错误:

回溯:

dumping stdin to local file /tmp/pyes_mrjob.testuser.20131004.103251.998597/STDIN
Making directory hdfs:///user/testuser/tmp/mrjob/pyes_mrjob.user.20131004.103251.998597/files/ on HDFS
> /usr/lib/hadoop-mapreduce/bin/hadoop fs -mkdir hdfs:///user/testuser/tmp/mrjob/pyes_mrjob.testuser.20131004.103251.998597/files/
Traceback (most recent call last):
  File "pyes_mrjob.py", line 34, in <module>
    MRWordFrequencyCount.run()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/job.py", line 500, in run
    mr_job.execute()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/job.py", line 518, in execute
    super(MRJob, self).execute()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/launch.py", line 146, in execute
    self.run_job()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/launch.py", line 207, in run_job
    runner.run()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/runner.py", line 458, in run
    self._run()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/hadoop.py", line 236, in _run
    self._upload_local_files_to_hdfs()
  File "/usr/local/lib/python2.7/dist-packages/mrjob/hadoop.py", line 263, in _upload_local_files_to_hdfs
    self._mkdir_on_hdfs(self._upload_mgr.prefix)
  File "/usr/local/lib/python2.7/dist-packages/mrjob/hadoop.py", line 271, in _mkdir_on_hdfs
    self.invoke_hadoop(['fs', '-mkdir', path])
  File "/usr/local/lib/python2.7/dist-packages/mrjob/fs/hadoop.py", line 81, in invoke_hadoop
    proc = Popen(args, stdout=PIPE, stderr=PIPE)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

我手动执行命令，它在那里工作正常，但是当我尝试执行我的程序时，它不起作用。由于刚开始学习，有人可以建议我必须选择哪个图书馆。根据一些博客，一些图书馆有很好的文档，一些图书馆有更好的性能......我在下面看到了看起来更旧的帖子 http://blog.cloudera.com/blog/2013/01/a-guide-to-python-frameworks-for-hadoop/

但是最近很多图书馆都得到了更新。所以有人可以建议我可以开始的图书馆..

Answer 1

我猜这个问题是由于 mrjob 调用“hadoop fs -mkdir”的方式引起的，如果你想要创建的目标目录的父目录不存在，-mkdir 将失败。这意味着您必须使用“hadoop fs -mkdir -p [path]”。最后，你需要在[mrjob安装路径](我的是/usr/lib/python2.6/site-packages/mrjob)/hadoop.py 271行手动修改mrjob库:

self.invoke_hadoop(['fs', '-mkdir', path])

到

self.invoke_hadoop(['fs', '-mkdir', '-p', path])

祝你好运!