python - PipeMapRed.waitOutputThreads(): subproces

Recently, I want to parse websites and then use BeautifulSoup to filter what I want and write in csv file in hdfs.

Now, I am at the process of filtering website code with BeautifulSoup.

I want to use mapreduce method to execute it:

hadoop jar /usr/lib/hadoop-0.20-mapreduce/contrib/streaming/hadoop-streaming-2.3.0-mr1-cdh5.0.2.jar 
-mapper /pytemp/filter.py 
-input /user/root/py/input/ 
-output /user/root/py/output40/

input file is like kvs(PER LINE): (key, value) = (url, content)

content, I mean:

<html><head><title>...</title></head><body>...</body></html>

filter.py file:

#!/usr/bin/env python
#!/usr/bin/python
#coding:utf-8
from bs4 import BeautifulSoup
import sys

for line in sys.stdin:
    line = line.strip()
    key, content = line.split(",")

    #if the following two lines do not exist, the program will execute successfully
    soup = BeautifulSoup(content)
    output = soup.find()         

    print("Start-----------------")
    print("End------------------")

BTW, I think I do not need reduce.py to do my work.

However, I got error message:

Error: java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 1
at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:320)
at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:533)
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:430)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:342)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:168)
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:1548)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:163)

Here is a reply said it is memory issue but my input file just 3MB. http://grokbase.com/t/gg/rhadoop/13924fs4as/972-getting-error-pipemapred-waitoutputthreads-while-running-mapreduce-program-for-40mb-of-sizedataset

I have no idea about my problem. I search lots of things for it but still does not work.

My environment is:

CentOS6
Python2.7
Cloudera CDH5

I will appreciate your help with this situation.

EDIT on 2016/06/24

First of all, I checked error log and found the problem is too many values to unpack. (also thanks to @kynan answer)

Just give an example why it happened

<font color="#0000FF">
  SomeText1
  <font color="#0000FF">
    SomeText2
  </font>
</font>

If part of content is like above, and I call soup.find("font", color="#0000FF") and assign to output. It will cause two font to be assigned to one output, so that is why the error too many values to unpack

Solution

Just change output = soup.find() to (Var1, Var2, ...) = soup.find_all("font", color="#0000FF", limit=AmountOfVar) and work well :)

This error usually means that the mapper process died. To find out why check the user logs in $HADOOP_PREFIX/logs/userlogs: there is one directory per job and inside one directory per container. In each container directory is a file stderr containing the output sent to stderr i.e. error messages.