hadoop学习日记二 运行程序

小雪崩

　　昨天搭建好了hadoop的环境，现在执行hadoop的例子验证一下。
　　在NameNode下建立两个文件

root@wenbo00:/home/wenbo# echo 'Hello world bye world' > file01
root@wenbo00:/home/wenbo# echo 'hello hadoop goodbye hadoop' > file02

　　在hdfs中建立一个input目录

root@wenbo00:/home/wenbo# hadoop fs -mkdir input
　　将刚才建好的两个文件复制到input目录下

root@wenbo00:/home/wenbo# hadoop fs -copyFromLocal file0* input

　　执行以下命令可以看到复制结果

root@wenbo00:/home/hadoop-1.0.1# hadoop fs -ls input/

 　　看到的结果为

Found 2 items
-rw-r--r--   1 root supergroup         22 2012-03-13 19:44 /user/root/input/file01
-rw-r--r--   1 root supergroup         28 2012-03-13 19:44 /user/root/input/file02

 　　执行hadoop自带的worldcount例子，并将结果输出到output目录中

root@wenbo00:/home/wenbo# hadoop jar /home/hadoop-1.0.1/hadoop-examples-1.0.1.jar wordcount input output
　　可以看到以下的输出log

****hdfs://wenbo00:9000/user/root/input
12/03/13 19:47:21 INFO input.FileInputFormat: Total input paths to process : 2
12/03/13 19:47:22 INFO mapred.JobClient: Running job: job_201203131940_0001
12/03/13 19:47:23 INFO mapred.JobClient:  map 0% reduce 0%
12/03/13 19:47:37 INFO mapred.JobClient:  map 50% reduce 0%
12/03/13 19:47:40 INFO mapred.JobClient:  map 100% reduce 0%
12/03/13 19:47:52 INFO mapred.JobClient:  map 100% reduce 100%
12/03/13 19:47:57 INFO mapred.JobClient: Job complete: job_201203131940_0001
12/03/13 19:47:57 INFO mapred.JobClient: Counters: 30
12/03/13 19:47:57 INFO mapred.JobClient:   Job Counters
12/03/13 19:47:57 INFO mapred.JobClient:     Launched reduce tasks=1
12/03/13 19:47:57 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=19732
12/03/13 19:47:57 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0
12/03/13 19:47:57 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0
12/03/13 19:47:57 INFO mapred.JobClient:     Rack-local map tasks=1
12/03/13 19:47:57 INFO mapred.JobClient:     Launched map tasks=2
12/03/13 19:47:57 INFO mapred.JobClient:     Data-local map tasks=1
12/03/13 19:47:57 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=14004
12/03/13 19:47:57 INFO mapred.JobClient:   File Output Format Counters
12/03/13 19:47:57 INFO mapred.JobClient:     Bytes Written=49
12/03/13 19:47:57 INFO mapred.JobClient:   FileSystemCounters
12/03/13 19:47:57 INFO mapred.JobClient:     FILE_BYTES_READ=79
12/03/13 19:47:57 INFO mapred.JobClient:     HDFS_BYTES_READ=264
12/03/13 19:47:57 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=64654
12/03/13 19:47:57 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=49
12/03/13 19:47:57 INFO mapred.JobClient:   File Input Format Counters
12/03/13 19:47:57 INFO mapred.JobClient:     Bytes Read=50
12/03/13 19:47:57 INFO mapred.JobClient:   Map-Reduce Framework
12/03/13 19:47:57 INFO mapred.JobClient:     Map output materialized bytes=85
12/03/13 19:47:57 INFO mapred.JobClient:     Map input records=2
12/03/13 19:47:57 INFO mapred.JobClient:     Reduce shuffle bytes=85
12/03/13 19:47:57 INFO mapred.JobClient:     Spilled Records=12
12/03/13 19:47:57 INFO mapred.JobClient:     Map output bytes=82
12/03/13 19:47:57 INFO mapred.JobClient:     CPU time spent (ms)=3000
12/03/13 19:47:57 INFO mapred.JobClient:     Total committed heap usage (bytes)=336404480
12/03/13 19:47:57 INFO mapred.JobClient:     Combine input records=8
12/03/13 19:47:57 INFO mapred.JobClient:     SPLIT_RAW_BYTES=214
12/03/13 19:47:57 INFO mapred.JobClient:     Reduce input records=6
12/03/13 19:47:57 INFO mapred.JobClient:     Reduce input groups=6
12/03/13 19:47:57 INFO mapred.JobClient:     Combine output records=6
12/03/13 19:47:57 INFO mapred.JobClient:     Physical memory (bytes) snapshot=384741376
12/03/13 19:47:57 INFO mapred.JobClient:     Reduce output records=6
12/03/13 19:47:57 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=1573851136
12/03/13 19:47:57 INFO mapred.JobClient:     Map output records=8

　　最终计算结果为8个单词
　　可以查看output中的输出查看以下
　　利用以下命令可以查看output文件夹下的生成文件

root@wenbo00:/home/hadoop-1.0.1# hadoop fs -ls output

　　结果为

Found 3 items
-rw-r--r--   1 root supergroup          0 2012-03-13 19:47 /user/root/output/_SUCCESS
drwxr-xr-x   - root supergroup          0 2012-03-13 19:47 /user/root/output/_logs
-rw-r--r--   1 root supergroup         49 2012-03-13 19:47 /user/root/output/part-r-00000

　　part-r-00000中存放了执行的结果

root@wenbo00:/home/hadoop-1.0.1# hadoop fs -cat output/part-r-00000

　　结果为

Hello   1
bye     1
goodbye 1
hadoop  2
hello   1
world   2

　　共8个单词，执行成功。