本节书摘来自华章社区《Hadoop大数据分析与挖掘实战》一书中的第2章，第2.4节动手实践，作者张良均 樊哲 赵云龙 李成华 ，更多章节内容可以访问云栖社区“华章社区”公众号查看
2.4 动手实践
按照2.2节的详细配置步骤进行操作，部署完成后即可进行下面的实验。
实践一：HDFS命令
1）新建文件夹。hadoop fs -mkdir /user
hadoop fs -mkdir /user/root2）查看文件夹权限。# hadoop fs -ls -d /user/root
drwxr-xr-x - root supergroup 0 2015-05-29 17:29 /user/root3）上传文件。
复制02-上机实验/ds.txt并通过xftp上传到客户端机器，运行下面的命令和结果对照。# hadoop fs -put ds.txt ds.txt
# hadoop fs -ls -R /user/root
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:07 /user/root/ds.txt4）查看文件内容。# hadoop fs -cat /user/root/ds.txt
17.759065824032646,0.6708203932499373
20.787886563063058,0.7071067811865472
17.944905786933322,0.5852349955359809
……5）复制/移动/删除文件。# hadoop fs -cp /user/root/ds.txt /user/root/ds_backup.txt
# hadoop fs -ls /user/root
Found 2 items
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:07 /user/root/ds.txt
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:30 /user/root/ds_backup.tx
# hadoop fs -mv /user/root/ds_backup.txt /user/root/ds_backup1.txt
# hadoop fs -ls /user/root
Found 2 items
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:07 /user/root/ds.txt
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:30 /user/root/ds_backup1.txt
# hadoop fs -rm -r /user/root/ds_backup1.txt
15/05/29 19:32:51 INFO fs.TrashPolicyDefault: Namenode trash configuration: Deletion interval = 0 minutes, Emptier interval = 0 minutes.
Deleted /user/root/ds_backup1.txt
# hadoop fs -ls /user/root
Found 1 items
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:07 /user/root/ds.txt实践二：MapReduce任务
1）复制02-上机实验/ds.txt并通过xftp上传到客户端机器/opt目录下。# hadoop fs -put /opt/ds.txt /user/root/ds.txt
# hadoop fs -ls /user/root
Found 1 items
-rw-r--r-- 3 root supergroup 9135 2015-05-29 19:49 /user/root/ds.txt2）复制Hadoop的安装目录的MapReduce Example的jar包到/opt目录下。# cp /opt/hadoop-2.6.0/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar /opt
# ls /opt/hadoop-mapreduce*
/opt/hadoop-mapreduce-examples-2.6.0.jar3）运行单词计数MapReduce任务。# hadoop jar /opt/hadoop-mapreduce-examples-2.6.0.jar wordcount /user/root/ds.txt /user/root/ds_out
15/05/29 20:23:00 INFO client.RMProxy: Connecting to ResourceManager at master/192.168.222.131:8032
15/05/29 20:23:02 INFO input.FileInputFormat: Total input paths to process : 1
15/05/29 20:23:02 INFO mapreduce.JobSubmitter: number of splits:1
15/05/29 20:23:02 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1432825607351_0127
15/05/29 20:23:03 INFO impl.YarnClientImpl: Submitted application application_1432825607351_0127
15/05/29 20:23:03 INFO mapreduce.Job: The url to track the job: http://master:8088/proxy/application_1432825607351_0127/
15/05/29 20:23:03 INFO mapreduce.Job: Running job: job_1432825607351_0127
15/05/29 20:23:15 INFO mapreduce.Job: Job job_1432825607351_0127 running in uber mode : false
15/05/29 20:23:15 INFO mapreduce.Job: map 0% reduce 0%
15/05/29 20:23:31 INFO mapreduce.Job: map 100% reduce 0%
15/05/29 20:23:40 INFO mapreduce.Job: map 100% reduce 100%
15/05/29 20:23:40 INFO mapreduce.Job: Job job_1432825607351_0127 completed successfully
15/05/29 20:23:40 INFO mapreduce.Job: Counters: 49
File System Counters
FILE: Number of bytes read=10341
FILE: Number of bytes written=232633
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=9236
HDFS: Number of bytes written=9375
HDFS: Number of read operations=6
HDFS: Number of large read operations=0
HDFS: Number of write operations=2
Job Counters
Launched map tasks=1
Launched reduce tasks=1
Data-local map tasks=1
Total time spent by all maps in occupied slots (ms)=12679
Total time spent by all reduces in occupied slots (ms)=6972
Total time spent by all map tasks (ms)=12679
Total time spent by all reduce tasks (ms)=6972
Total vcore-seconds taken by all map tasks=12679
Total vcore-seconds taken by all reduce tasks=6972
Total megabyte-seconds taken by all map tasks=12983296
Total megabyte-seconds taken by all reduce tasks=7139328
Map-Reduce Framework
Map input records=240
Map output records=240
Map output bytes=9855
Map output materialized bytes=10341
Input split bytes=101
Combine input records=240
Combine output records=240
Reduce input groups=240
Reduce shuffle bytes=10341
Reduce input records=240
Reduce output records=240
Spilled Records=480
Shuffled Maps =1
Failed Shuffles=0
Merged Map outputs=1
GC time elapsed (ms)=398
CPU time spent (ms)=5330
Physical memory (bytes) snapshot=321277952
Virtual memory (bytes) snapshot=2337296384
Total committed heap usage (bytes)=195235840
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=9135
File Output Format Counters
Bytes Written=93754）查看任务的输出。# hadoop fs -cat /user/root/ds_out/part-r-00000
16.75481160342442,0.5590169943749481 1
17.759065824032646,0.6708203932499373 1
17.944905786933322,0.5852349955359809 1
18.619213022043585,0.5024937810560444 1
18.664436259885097,0.7433034373659246 1
……
