在实例测试前先确保hadoop 启动正确
Master.Hadoop：
word 1
[[email protected] input]$ jps
6736 Jps
6036 NameNode
4697 SecondaryNameNode
4849 ResourceManager
[[email protected] input]$
Slave1.Hadoop
[[email protected] sources]$ jps
8086 SecondaryNameNode
8961 Jps
8320 NodeManager
7935 DataNode
在测试过程中遇到的错与与解决方案：
问题一：
[[email protected] input]$ hadoop fs -ls /
ls: Call From Master.Hadoop/192.168.160.131 to Master.Hadoop:9000 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused
解决方案：
1、格式化HDFS文件系统：hadoop namenode -format
问题二：
/home/hadoop/WordCount/input
[[email protected] input]$ hadoop fs -put ./ /input
15/06/30 17:10:45 WARN hdfs.DFSClient: DataStreamer Exception
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /input/input/test1.txt._COPYING_ could only be replicated to 0 nodes instead of minReplication (=1). There are 0 datanode(s) running and no node(s) are excluded in this operation.
at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget(BlockManager.java:1441)
解决方案：
1. 先执行stop-all.sh暂停所有服务
2. 将所有Salve节点上的tmp , logs 文件夹删除 ， 然后重新建立tmp , logs 文件夹
3. 格式化HDFS文件系统：hadoop namenode -format
转载地址：
http://linux.it.net.cn/e/cluster/hadoop/2014/1215/10427.html
转载内容：
装好的hadoop测试一1个示例程序WordCount，首先需要在操作系统上新建两个任意文件，然后上传到hadoop，再运行该程序统计文件中单词的个数，最后查看结果。
在操作系统上新建任意文件：
例如：
[[email protected] input]$ ls
test1.txt test2.txt
查看hadoop的文件系统目录
[[email protected] input]$ hadoop fs -ls /
Found 1 items
drwxr-xr-x - hadoop supergroup 0 2013-10-30 00:00 /input
上传至hadoop的/input下
[[email protected] input]$ hadoop fs -put ./ /input
[[email protected] input]$ hadoop fs -ls /input
Found 2 items
-rw-r--r-- 3 hadoop supergroup 12 2013-10-30 00:00 /input/test1.txt
-rw-r--r-- 3 hadoop supergroup 13 2013-10-30 00:00 /input/test2.txt
在hadoop文件系统命令查看这两个文件的内容：
[[email protected] test]$ hadoop fs -cat /input/test1.txt
hello world
[[email protected] test]$ hadoop fs -cat /input/test2.txt
hello hadoop
运行示例程序（WordCount)：
[[email protected] test]$ hadoop jar $HADOOP_HOME/share/hadoop/mapreduce/sources/hadoop-mapreduce-examples-2.2.0-sources.jar org.apache.hadoop.examples.WordCount /input /output
13/11/06 21:33:40 INFO Configuration.deprecation: session.id is deprecated. Instead, use dfs.metrics.session-id
13/11/06 21:33:40 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
13/11/06 21:33:40 INFO input.FileInputFormat: Total input paths to process : 2
13/11/06 21:33:41 INFO mapreduce.JobSubmitter: number of splits:2
13/11/06 21:33:41 INFO Configuration.deprecation: user.name is deprecated. Instead, use mapreduce.job.user.name
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.jar is deprecated. Instead, use mapreduce.job.jar
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.output.value.class is deprecated. Instead, use mapreduce.job.output.value.class IT网，http://www.it.net.cn
13/11/06 21:33:41 INFO Configuration.deprecation: mapreduce.combine.class is deprecated. Instead, use mapreduce.job.combine.class
13/11/06 21:33:41 INFO Configuration.deprecation: mapreduce.map.class is deprecated. Instead, use mapreduce.job.map.class
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.job.name is deprecated. Instead, use mapreduce.job.name
13/11/06 21:33:41 INFO Configuration.deprecation: mapreduce.reduce.class is deprecated. Instead, use mapreduce.job.reduce.class
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.input.dir is deprecated. Instead, use mapreduce.input.fileinputformat.inputdir
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.output.dir is deprecated. Instead, use mapreduce.output.fileoutputformat.outputdir
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.output.key.class is deprecated. Instead, use mapreduce.job.output.key.class
13/11/06 21:33:41 INFO Configuration.deprecation: mapred.working.dir is deprecated. Instead, use mapreduce.job.working.dir
13/11/06 21:33:41 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_local382050821_0001
13/11/06 21:33:41 WARN conf.Configuration: file:/hadoop/hdfs/tmp/hadoop-hadoop/mapred/staging/hadoop382050821/.staging/job_local382050821_0001/job.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval; Ignoring.
13/11/06 21:33:41 WARN conf.Configuration: file:/hadoop/hdfs/tmp/hadoop-hadoop/mapred/staging/hadoop382050821/.staging/job_local382050821_0001/job.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.attempts; Ignoring.
13/11/06 21:33:42 WARN conf.Configuration: file:/hadoop/hdfs/tmp/hadoop-hadoop/mapred/local/localRunner/hadoop/job_local382050821_0001/job_local382050821_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval; Ignoring. Linux学习，http:// linux.it.net.cn
13/11/06 21:33:42 WARN conf.Configuration: file:/hadoop/hdfs/tmp/hadoop-hadoop/mapred/local/localRunner/hadoop/job_local382050821_0001/job_local382050821_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.attempts; Ignoring.
13/11/06 21:33:42 INFO mapreduce.Job: The url to track the job: http://localhost:8080/
13/11/06 21:33:42 INFO mapreduce.Job: Running job: job_local382050821_0001
13/11/06 21:33:42 INFO mapred.LocalJobRunner: OutputCommitter set in config null
13/11/06 21:33:42 INFO mapred.LocalJobRunner: OutputCommitter is org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter
13/11/06 21:33:42 INFO mapred.LocalJobRunner: Waiting for map tasks
13/11/06 21:33:42 INFO mapred.LocalJobRunner: Starting task: attempt_local382050821_0001_m_000000_0
13/11/06 21:33:42 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ]
13/11/06 21:33:42 INFO mapred.MapTask: Processing split: hdfs://hadoop01:9000/input/test2.txt:0+13 Linux学习，http:// linux.it.net.cn
13/11/06 21:33:42 INFO mapred.MapTask: Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer
13/11/06 21:33:42 INFO mapred.MapTask: (EQUATOR) 0 kvi 26214396(104857584)
13/11/06 21:33:42 INFO mapred.MapTask: mapreduce.task.io.sort.mb: 100
13/11/06 21:33:42 INFO mapred.MapTask: soft limit at 83886080
13/11/06 21:33:42 INFO mapred.MapTask: bufstart = 0; bufvoid = 104857600
13/11/06 21:33:42 INFO mapred.MapTask: kvstart = 26214396; length = 6553600
13/11/06 21:33:43 INFO mapred.LocalJobRunner:
13/11/06 21:33:43 INFO mapred.MapTask: Starting flush of map output
13/11/06 21:33:43 INFO mapred.MapTask: Spilling map output
13/11/06 21:33:43 INFO mapred.MapTask: bufstart = 0; bufend = 21; bufvoid = 104857600
13/11/06 21:33:43 INFO mapred.MapTask: kvstart = 26214396(104857584); kvend = 26214392(104857568); length = 5/6553600
13/11/06 21:33:43 INFO mapred.MapTask: Finished spill 0
13/11/06 21:33:43 INFO mapred.Task: Task:attempt_local382050821_0001_m_000000_0 is done. And is in the process of committing
13/11/06 21:33:43 INFO mapreduce.Job: Job job_local382050821_0001 running in uber mode : false
13/11/06 21:33:43 INFO mapreduce.Job: map 0% reduce 0%
13/11/06 21:33:43 INFO mapred.LocalJobRunner: map
13/11/06 21:33:43 INFO mapred.Task: Task ‘attempt_local382050821_0001_m_000000_0‘ done.
13/11/06 21:33:43 INFO mapred.LocalJobRunner: Finishing task: attempt_local382050821_0001_m_000000_0
13/11/06 21:33:43 INFO mapred.LocalJobRunner: Starting task: attempt_local382050821_0001_m_000001_0
13/11/06 21:33:43 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ]
13/11/06 21:33:43 INFO mapred.MapTask: Processing split: hdfs://hadoop01:9000/input/test1.txt:0+12
13/11/06 21:33:43 INFO mapred.MapTask: Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer
13/11/06 21:33:43 INFO mapred.MapTask: (EQUATOR) 0 kvi 26214396(104857584)
13/11/06 21:33:43 INFO mapred.MapTask: mapreduce.task.io.sort.mb: 100
13/11/06 21:33:43 INFO mapred.MapTask: soft limit at 83886080
13/11/06 21:33:43 INFO mapred.MapTask: bufstart = 0; bufvoid = 104857600
13/11/06 21:33:43 INFO mapred.MapTask: kvstart = 26214396; length = 6553600
13/11/06 21:33:43 INFO mapred.LocalJobRunner:
13/11/06 21:33:43 INFO mapred.MapTask: Starting flush of map output
13/11/06 21:33:43 INFO mapred.MapTask: Spilling map output
13/11/06 21:33:43 INFO mapred.MapTask: bufstart = 0; bufend = 20; bufvoid = 104857600
13/11/06 21:33:43 INFO mapred.MapTask: kvstart = 26214396(104857584); kvend = 26214392(104857568); length = 5/6553600
13/11/06 21:33:43 INFO mapred.MapTask: Finished spill 0
13/11/06 21:33:43 INFO mapred.Task: Task:attempt_local382050821_0001_m_000001_0 is done. And is in the process of committing
13/11/06 21:33:43 INFO mapred.LocalJobRunner: map
13/11/06 21:33:43 INFO mapred.Task: Task ‘attempt_local382050821_0001_m_000001_0‘ done.
13/11/06 21:33:43 INFO mapred.LocalJobRunner: Finishing task: attempt_local382050821_0001_m_000001_0
13/11/06 21:33:43 INFO mapred.LocalJobRunner: Map task executor complete.
13/11/06 21:33:43 INFO mapred.Task: Using ResourceCalculatorProcessTree : [ ]
13/11/06 21:33:43 INFO mapred.Merger: Merging 2 sorted segments
13/11/06 21:33:43 INFO mapred.Merger: Down to the last merge-pass, with 2 segments left of total size: 36 bytes
13/11/06 21:33:43 INFO mapred.LocalJobRunner:
13/11/06 21:33:43 INFO Configuration.deprecation: mapred.skip.on is deprecated. Instead, use mapreduce.job.skiprecords
13/11/06 21:33:44 INFO mapreduce.Job: map 100% reduce 0%
13/11/06 21:33:44 INFO mapred.Task: Task:attempt_local382050821_0001_r_000000_0 is done. And is in the process of committing
13/11/06 21:33:44 INFO mapred.LocalJobRunner:
13/11/06 21:33:44 INFO mapred.Task: Task attempt_local382050821_0001_r_000000_0 is allowed to commit now
13/11/06 21:33:44 INFO output.FileOutputCommitter: Saved output of task ‘attempt_local382050821_0001_r_000000_0‘ to hdfs://hadoop01:9000/output/_temporary/0/task_local382050821_0001_r_000000
13/11/06 21:33:44 INFO mapred.LocalJobRunner: reduce > reduce
13/11/06 21:33:44 INFO mapred.Task: Task ‘attempt_local382050821_0001_r_000000_0‘ done.
13/11/06 21:33:45 INFO mapreduce.Job: map 100% reduce 100%
13/11/06 21:33:45 INFO mapreduce.Job: Job job_local382050821_0001 completed successfully
13/11/06 21:33:45 INFO mapreduce.Job: Counters: 32
File System Counters
FILE: Number of bytes read=812174
FILE: Number of bytes written=1395157
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=63
HDFS: Number of bytes written=25
HDFS: Number of read operations=25
HDFS: Number of large read operations=0
HDFS: Number of write operations=5
Map-Reduce Framework
Map input records=2
Map output records=4
Map output bytes=41
Map output materialized bytes=61
Input split bytes=202
Combine input records=4
Combine output records=4
Reduce input groups=3
Reduce shuffle bytes=0
Reduce input records=4
Reduce output records=3
Spilled Records=8
Shuffled Maps =0
Failed Shuffles=0
Merged Map outputs=0
GC time elapsed (ms)=146
CPU time spent (ms)=0
Physical memory (bytes) snapshot=0
Virtual memory (bytes) snapshot=0 IT网，http://www.it.net.cn
Total committed heap usage (bytes)=456732672
File Input Format Counters
Bytes Read=25
File Output Format Counters
Bytes Written=25
查看程序运行结果：
[[email protected] test]$ hadoop fs -cat /output/part-r-00000
hadoop 1
hello 2
world 1