hadoop-streaming issue

[ghost]

Hi,
This repo really help me a lot, thank for your kindness.
However I run python script with hadoop-streaming jar and it stop at map 100% reduce 0%
and then I go to dashboard and find reducer is stop at STATING, which word count example is work perfect.

hadoop jar hadoop-streaming.jar \
-files mapper.py,reducer.py \
-mapper "python mapper.py" \
-reducer "python reducer.py" \
-input streaming-data \
-output streaming-output

And I run it by local command, it also work

cat data/* | python mapper.py | sort | python reducer.py

http://www.sunlab.org/teaching/cse6250/fall2017/lab/hadoop-streaming/

Where can I find out office python example, to clarify where is the problem?