Hadoop：無法運行 MapReduce 作業（python）

Question

我正在嘗試使用 Hadoop 運行一個簡單的 Map-Reduce 作業，但我似乎無法讓它工作。

映射器代碼：

#!/usr/bin/python
import json
import sys

#can't really do anything in the reducer most of the time, there's no computations the reducer need to process
jsonString = ''

for line in sys.stdin:
    line = line.strip()
    try:
        convertedData = json.loads(line)

        #Sometimes we pass in an invalid title, so need to check if medianPay is empty
        if convertedData['success'] == True:
            lowPay = str(convertedData['response']['payLow'])
            #medianPay = str(convertedData['response']['payMedian'])
            highPay = str(convertedData['response']['payHigh'])

            #adding national to identify this data as national data
            if lowPay:
                print convertedData['response']['jobTitle'] + '\t' 'lowPay:'+ lowPay
                #print convertedData['response']['jobTitle'] + '\t' 'medianPay:'+ medianPay
                print convertedData['response']['jobTitle'] + '\t' 'highPay:'+ highPay
    except ValueError:
        pass

減速器代碼：#!/usr/bin/python from future import Division import sys

curJobTitle = ''
lowSalary = 0;
highSalary = 0;

for line in sys.stdin:      
    line = line.strip()
    items = line.split('\t')        
    key, value = line.split('\t')   
    if key != curJobTitle:      
        if (curJobTitle != ''):
            percent_diff = ((highSalary - lowSalary)/((lowSalary + highSalary) / 2)) * 100
            print curJobTitle + ':' + str(abs(percent_diff))

        curJobTitle = key
        type, salary = value.split(':')     
        if type == 'lowPay':
            lowSalary = float(salary)
        elif type == 'highPay':
            highSalary = float(salary)
    else:
        type, salary = value.split(':')     
        if type == 'lowPay':
            lowSalary = float(salary)
        elif type == 'highPay':
            highSalary = float(salary)

if lowSalary != 0 and highSalary != 0:
    percent_diff = ((highSalary - lowSalary)/((lowSalary + highSalary) / 2)) * 100
    print curJobTitle + ':' + str(abs(percent_diff))

端子 output：

16/05/04 17:30:30 INFO mapreduce.Job:  map 0% reduce 0%
16/05/04 17:30:36 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000001_0, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000003/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

Container killed by the ApplicationMaster.
Container killed on request. Exit code is 143
Container exited with a non-zero exit code 143

16/05/04 17:30:36 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000000_0, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000002/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

16/05/04 17:30:40 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000001_1, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000004/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

16/05/04 17:30:41 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000000_1, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000005/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

16/05/04 17:30:44 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000001_2, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000006/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

16/05/04 17:30:45 INFO mapreduce.Job: Task Id : attempt_1461978900532_0179_m_000000_2, Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
        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:1657)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:162)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 9 more
Caused by: java.lang.RuntimeException: Error in configuring object
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112)
        at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136)
        at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38)
        ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
        ... 17 more
Caused by: java.lang.RuntimeException: configuration exception
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
        at org.apache.hadoop.streaming.PipeMapper.configure(PipeMapper.java:66)
        ... 22 more
Caused by: java.io.IOException: Cannot run program "/hadoop/yarn/local/usercache/tsahn001/appcache/application_1461978900532_0179/container_e17_1461978900532_0179_01_000007/./NationalSalaryMapper.py": error=2, No such file or directory
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
        at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
        ... 23 more
Caused by: java.io.IOException: error=2, No such file or directory
        at java.lang.UNIXProcess.forkAndExec(Native Method)
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:187)
        at java.lang.ProcessImpl.start(ProcessImpl.java:130)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
        ... 24 more

我已經使用 cat | 在本地測試了我的 MapReduction 代碼。 |，並且它似乎運行正常。 但是，每當我嘗試在 Hadoop 上運行 MapReduce 作業時，我總是會收到錯誤消息（上面是一個示例。我正在運行我的作業：

hadoop jar /usr/hdp/2.3.4.0-3485/hadoop-mapreduce/hadoop-streaming.jar \ -file /home/tsahn001/MapReduceCode/NationalSalaryMapper.py -mapper 'NationalSalaryMapper.py' \ -file /home/tsahn001/MapReduceCode/NationalSalaryReducer.py -reducer 'NationalSalaryReducer.py' \ -input data/glassdoor_national_data -output test_national

我的 map reduce 是否因為我試圖執行它而無法工作？ 如果是這樣，我該如何解決這個問題？

Answer 1

您的映射器應該使用sys.stdout將鍵值對發送給reducer，而不是使用print語句。 例如，代替：

print convertedData['response']['jobTitle'] + '\t' 'lowPay:'+ lowPay

您的映射器應該像這樣向reducer發出：

emit_string = convertedData['response']['jobTitle'] + '|' 'lowPay:'+ lowPay
sys.stdout.write("{0}\t1\n".format(emit_string)

注意選項卡（\\ t）和發射中的值1。 我還用管道符號替換了打印語句中的選項卡，因為減速器將使用該選項卡來分隔鍵（字符串）和值（計數）。

Answer 2

根據輸出的錯誤，表明您為python腳本指定了錯誤的路徑，原因：java.io.IOException：error = 2，沒有此類文件或目錄檢查路徑，然后重試。

祝好運 ！

Answer 3

我有類似的問題。 有誰能解決嗎？