成功搭建Hadoop集群后简单实验

1> 检查对HDFS的访问(在namenode上操作)

#./hadoop-0.20.2/bin/hadoop fs -ls

2> hadoop中的文件系统操作

#./hadoop-0.20.2/bin/hadoop fs -mkdir test

#./hadoop-0.20.2/bin/hadoop fs -ls test

#./hadoop-0.20.2/bin/hadoop fs -rmr test

3> 测试hadoop

a> 创建子目录

#./hadoop-0.20.2/bin/hadoop fs -mkdir input

b> 把本地文件移动到hdfs

#./hadoop-0.20.2/bin/hadoop fs -put /usr/share/doc/pam-1.1.1/rfc86.0.txt input

#./hadoop-0.20.2/bin/hadoop fs -put /usr/share/doc/pam-1.1.1/linux-PAM_SAG.txt input

c> 查看文件是否存在

#./hadoop-0.20.2/bin/hadoop fs -ls input

d> 执行计算单词频率的MaPReduce作业

#./hadoop-0.20.2/bin/hadoop jar /root/hadoop-0.20.2/hadoop-0.20.2-examples.jarWordcount input output

Found 2 items

drwxr-xr-x - root supergroup 0 2012-11-26 04:25 /user/root/output/_logs

-rw-r--r-- 2 root supergroup 8315 2012-11-26 04:25 /user/root/output/part-r-00000

e> 查看输出结果

#./hadoop-0.20.2/bin/hadoop fs -ls output

#./hadoop-0.20.2/bin/hadoop fs -cat output/part-r-00000 | head -n 13

f> 从HDFS提取输出

#./hadoop-0.20.2/bin/hadoop fs -get output/part-r-00000 output.txt