1320 DataNode1665 ResourceManager
1771 NodeManager
1195 NameNode
1487 SecondaryNameNode

hadoop yarn
mapreduce
hello redis
java hadoop
hello world
here we go

pom.xml文件<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>hadoop-yarn</groupId><artifactId>hadoop-demo</artifactId><version>0.0.1-SNAPSHOT</version><dependencies><dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-mapreduce-client-core</artifactId><version>2.1.1-beta</version></dependency><dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-common</artifactId><version>2.1.1-beta</version></dependency><dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-mapreduce-client-common</artifactId><version>2.1.1-beta</version></dependency><dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-mapreduce-client-jobclient</artifactId><version>2.1.1-beta</version></dependency></dependencies>
</project>

package com.yhh.mapreduce.wordcount;
import java.io.IOException;import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;public class WordCountMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text,IntWritable>  {@Overridepublic void map(LongWritable key, Text value,OutputCollector<Text, IntWritable> output, Reporter reporter)throws IOException {String line = value.toString();if(line != null) {String[] words = line.split(" ");for(String word:words) {output.collect(new Text(word), new IntWritable(1));}}}}

package com.yhh.mapreduce.wordcount;import java.io.IOException;
import java.util.Iterator;import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;public class WordCountReducer extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable>{@Overridepublic void reduce(Text key, Iterator<IntWritable> values,OutputCollector<Text, IntWritable> output, Reporter reporter)throws IOException {int count = 0;while(values.hasNext()) {values.next();count++;}output.collect(key, new IntWritable(count));}}

package com.yhh.mapreduce.wordcount;import java.io.IOException;import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;public class WordCount {public static void main(String[] args) throws IOException {if(args.length != 2) {System.err.println("Error!");System.exit(1);}JobConf conf = new JobConf(WordCount.class);conf.setJobName("word count mapreduce demo");conf.setMapperClass(WordCountMapper.class);conf.setReducerClass(WordCountReducer.class);conf.setOutputKeyClass(Text.class);conf.setOutputValueClass(IntWritable.class);FileInputFormat.addInputPath(conf, new Path(args[0]));FileOutputFormat.setOutputPath(conf, new Path(args[1]));JobClient.runJob(conf);}}

[root@hadoop-namenodenew ~]# ll wordcount.jar
-rw-r--r--. 1 root root 4401 6月   1 22:05 wordcount.jar

hadoop jar ~/wordcount.jar com.yhh.mapreduce.wordcount.WordCount data.txt /wordcount/result

14/06/01 22:06:25 INFO mapreduce.Job: The url to track the job: http://hadoop-namenodenew:8088/proxy/application_1401631066126_0003/
14/06/01 22:06:25 INFO mapreduce.Job: Running job: job_1401631066126_0003
14/06/01 22:06:33 INFO mapreduce.Job: Job job_1401631066126_0003 running in uber mode : false
14/06/01 22:06:33 INFO mapreduce.Job:  map 0% reduce 0%
14/06/01 22:06:40 INFO mapreduce.Job:  map 50% reduce 0%
14/06/01 22:06:41 INFO mapreduce.Job:  map 100% reduce 0%
14/06/01 22:06:47 INFO mapreduce.Job:  map 100% reduce 100%
14/06/01 22:06:48 INFO mapreduce.Job: Job job_1401631066126_0003 completed successfully
14/06/01 22:06:49 INFO mapreduce.Job: Counters: 43

hadoop fs -cat /wordcount/result/part-00000go    1
hadoop    2
hello    2
here    1
java    1
mapreduce    1
redis    1
we    1
world    1
yarn    1