wiki:Hadoop_Lab4

Version 11 (modified by waue, 15 years ago) (diff)

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實做四: Hadoop 程式編譯

練習 1 : Word Count 初級版

  • 上傳內容到hdfs內
$ cd /opt/hadoop
$ mkdir lab4_input
$ echo "I like NCHC Cloud Course." > lab4_input/input1
$ echo "I like nchc Cloud Course, and we enjoy this course." > lab4_input/input2
$ bin/hadoop fs -put lab4_input lab4_input
$ bin/hadoop fs -ls lab4_input
  • 下載 WordCount.java 並存到/opt/hadoop;
    $ wget http://trac.nchc.org.tw/cloud/attachment/wiki/jazz/Hadoop_Lab6/WordCount.java?format=raw
    $ mv WordCount.java\?format\=raw WordCount.java
    
  • 運作程式
$ mkdir MyJava
$ javac -classpath hadoop-*-core.jar -d MyJava WordCount.java
$ jar -cvf wordcount.jar -C MyJava .
$ bin/hadoop jar wordcount.jar WordCount lab4_input/ lab4_out1/
$ bin/hadoop fs -cat lab4_out1/part-00000
  • lab4_out1 執行結果
    Cloud 2
    Course, 1
    Course. 1
    I 2
    NCHC  1
    and 1
    course. 1
    enjoy 1
    like  2
    nchc  1
    this  1
    we  1
    

練習 2 : Word Count 進階版

$ echo "\." >pattern.txt && echo "\," >>pattern.txt
$ bin/hadoop fs -put pattern.txt ./
$ mkdir MyJava2
  • 下載 WordCount2.java 並存到/opt/hadoop;
    $ wget http://trac.nchc.org.tw/cloud/attachment/wiki/jazz/Hadoop_Lab6/WordCount2.java?format=raw
    $ mv WordCount2.java\?format\=raw WordCount2.java
    
$ javac -classpath hadoop-*-core.jar -d MyJava2 WordCount2.java
$ jar -cvf wordcount2.jar -C MyJava2 .
$ bin/hadoop jar wordcount2.jar WordCount2 lab4_input lab4_out2 -skip pattern.txt
$ bin/hadoop fs -cat lab4_out2/part-00000
  • lab4_out2 執行結果
    Cloud 2
    Course  2
    I 2
    NCHC  1
    and 1
    course  1
    enjoy 1
    like  2
    nchc  1
    this  1
    we  1
    
$ bin/hadoop jar wordcount2.jar WordCount2 -Dwordcount.case.sensitive=false lab4_input lab4_out3 -skip pattern.txt
$ bin/hadoop fs -cat lab4_out3/part-00000
  • lab4_out3 執行結果
    and 1
    cloud 2
    course  3
    enjoy 1
    i 2
    like  2
    nchc  2
    this  1
    we  1
    

Hadoop 運算時出錯

日誌名稱的格式為

hadoop-使用者-工作身份-主機.副檔名

因此,

  • 運作於 pc121 主機上的 namenode 的日誌為
    • hadoop-hadooper-namenode-pc121.log
  • 運作於 pc122 主機上的 datanode 的日誌為
    • hadoop-hadooper-datanode-pc122.log
  • 運作於 pc123 主機上的 jobtracker 的日誌為
    • hadoop-hadooper-jobtracker-pc123.log
  • 運作於 pc124 主機上的 tasktracker 的日誌為
    • hadoop-hadooper-tasktracker-pc124.log

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