本节主要使用hadoop自带的程序运行demo来确认环境是否正常
1.首先创建一个input.txt文件，里面任意输入些单词，有部分重复单词
2.将input文件拷贝到hdfs
3.执行hadoop程序
4.查看结果
完整执行命令及返回结果看下面的执行拷贝
[root@master ~]#
[root@master ~]# ll /home/input.txt
-rw-r--r--. 1 root root 76 Sep 2 00:55 /home/input.txt
[root@master ~]# cat /home/input.txt
this is a test
hello hadoop
hadoop is a xxxxx
from changw.xiao@qq.com[root@master ~]#
[root@master ~]#
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -ls /
[root@master ~]#
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -copyFromLocal /home/input.txt /hdfs-input.txt
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -ls /
Found 1 items
-rw-r--r-- 2 root supergroup 76 2017-09-02 00:57 /hdfs-input.txt
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -cat /hdfs-input.txt
this is a test
hello hadoop
hadoop is a xxxxx
from changw.xiao@qq.com[root@master ~]#
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop jar /home/hadoop-2.7.4/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.4.jar wordcount /hdfs-input.txt /wordcount-result
17/09/02 00:59:28 INFO client.RMProxy: Connecting to ResourceManager at master/192.168.0.80:8032
17/09/02 00:59:29 INFO input.FileInputFormat: Total input paths to process : 1
17/09/02 00:59:29 INFO mapreduce.JobSubmitter: number of splits:1
17/09/02 00:59:30 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1504320356950_0001
17/09/02 00:59:31 INFO impl.YarnClientImpl: Submitted application application_1504320356950_0001
17/09/02 00:59:31 INFO mapreduce.Job: The url to track the job: http://master:8088/proxy/application_1504320356950_0001/
17/09/02 00:59:31 INFO mapreduce.Job: Running job: job_1504320356950_0001
17/09/02 00:59:44 INFO mapreduce.Job: Job job_1504320356950_0001 running in uber mode : false
17/09/02 00:59:44 INFO mapreduce.Job: map 0% reduce 0%
17/09/02 00:59:53 INFO mapreduce.Job: map 100% reduce 0%
17/09/02 01:00:00 INFO mapreduce.Job: map 100% reduce 100%
17/09/02 01:00:01 INFO mapreduce.Job: Job job_1504320356950_0001 completed successfully
17/09/02 01:00:01 INFO mapreduce.Job: Counters: 49
File System Counters
FILE: Number of bytes read=118
FILE: Number of bytes written=241861
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=174
HDFS: Number of bytes written=76
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)=6234
Total time spent by all reduces in occupied slots (ms)=4978
Total time spent by all map tasks (ms)=6234
Total time spent by all reduce tasks (ms)=4978
Total vcore-milliseconds taken by all map tasks=6234
Total vcore-milliseconds taken by all reduce tasks=4978
Total megabyte-milliseconds taken by all map tasks=6383616
Total megabyte-milliseconds taken by all reduce tasks=5097472
Map-Reduce Framework
Map input records=6
Map output records=12
Map output bytes=118
Map output materialized bytes=118
Input split bytes=98
Combine input records=12
Combine output records=9
Reduce input groups=9
Reduce shuffle bytes=118
Reduce input records=9
Reduce output records=9
Spilled Records=18
Shuffled Maps =1
Failed Shuffles=0
Merged Map outputs=1
GC time elapsed (ms)=173
CPU time spent (ms)=1380
Physical memory (bytes) snapshot=298201088
Virtual memory (bytes) snapshot=4159512576
Total committed heap usage (bytes)=139833344
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=76
File Output Format Counters
Bytes Written=76
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -ls /
Found 3 items
-rw-r--r-- 2 root supergroup 76 2017-09-02 00:57 /hdfs-input.txt
drwx------ - root supergroup 0 2017-09-02 00:59 /tmp
drwxr-xr-x - root supergroup 0 2017-09-02 00:59 /wordcount-result
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -ls /wordcount-result
Found 2 items
-rw-r--r-- 2 root supergroup 0 2017-09-02 00:59 /wordcount-result/_SUCCESS
-rw-r--r-- 2 root supergroup 76 2017-09-02 00:59 /wordcount-result/part-r-00000
[root@master ~]# /home/hadoop-2.7.4/bin/hadoop fs -cat /wordcount-result/part-r-00000
a 2
changw.xiao@qq.com 1
from 1
hadoop 2
hello 1
is 2
test 1
this 1
xxxxx 1
[root@master ~]#
[root@master ~]#
/home/hadoop-2.7.4/bin/hadoop fs -copyFromLocal /home/input.txt /hdfs-input.txt 也可以用 -put