[英]Hadoop MapReduce function is giving an error. Streaming Command Failed
將mapper.py、reducer.py、count_word_data.txt文件保存在C:\BigData\Hadoop-3.2.2目錄下。
給出初始命令
hadoop-3.2.2\bin\>hdfs fs -mkdir input
hadoop-3.2.2\bin\>hdfs fs -copyFromLocal C:\BigData\Hadoop-3.2.2\count_word_data.txt /input
映射器.py
#!/usr/bin/python -O
import sys
for line in sys.stdin:
line = line.strip()
keys = line.split()
for key in keys:
value = 1
print("{}".format(key)," {} ".format(value))
減速器.py
#!/usr/bin/python -O
import sys
last_key = None
running_total = 0
for input_line in sys.stdin:
input_line = input_line.strip()
this_key, value = input_line.split("\t", 1)
value = int(value)
if last_key == this_key:
running_total += value
else:
if last_key:
print( "%s\t%d" % (last_key, running_total) )
running_total = value
last_key = this_key
if last_key == this_key:
print( "%s\t%d" % (last_key, running_total) )
要運行這些 python 文件,我使用了 Hadoop 命令
Hadoop jar C:/BigData/hadoop-3.2.2/share/Hadoop/tools/lib/hadoop-streaming-3.2.2.jar -mapper “python C:/BigData/hadoop-3.2.2/mapper.py” -reducer “C:/BigData/hadoop-3.2.2/reducer.py” -input “input/count_word_data.txt” -output “input/output”
之后它給了我這個錯誤
雖然我已經在系統環境變量中正確指定了所有路徑(Python,Hadoop,JAVA,SPARK)。我不知道為什么我會遇到這個錯誤。
2022-02-10 18:33:09,065 INFO Configuration.deprecation: mapred.job.id is deprecated. Instead, use mapreduce.job.id
2022-02-10 18:33:09,065 INFO Configuration.deprecation: user.name is deprecated. Instead, use mapreduce.job.user.name
2022-02-10 18:33:09,066 INFO Configuration.deprecation: mapred.task.partition is deprecated. Instead, use mapreduce.task.partition
2022-02-10 18:33:09,075 ERROR streaming.PipeMapRed: configuration exception
java.io.IOException: Cannot run program "python": CreateProcess error=2, The system cannot find the file specified
at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1128)
at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1071)
at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.jav
該系統找不到指定的文件
這個問題與Hadoop沒有直接關系。
任何一個:
python
未安裝(或在您的 Windows PATH
上)。 要解決此問題,請確保您可以運行python -V
,它會顯示已安裝的版本。-files C:\path\to\mapper.py,C:\path\to\reducer.py
。您也不需要在輸入或 output 路徑上加引號。
我還要指出 PySpark 可以說是更好/更簡單的字數統計方法,它不需要 HDFS。
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