Eclipse远程提交MapReduce任务到Hadoop集群

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一、介绍

以前写完MapReduce任务以后总是打包上传到Hadoop集群，然后通过shell命令去启动任务，然后在各个节点上去查看Log日志文件，后来为了提高开发效率，需要找到通过Ecplise直接将MaprReduce任务直接提交到Hadoop集群中。该章节讲述用户如何从Eclipse的压缩包最终完成Eclipse提价任务给MapReduce集群。

二、详解

1、安装Eclipse，安装hadoop插件

（1）首先下载Eclipse的压缩包，然后可以从这里下载hadoop 2.7.1的ecplise插件和其他一些搭建环境中所需要的文件，然后解压ecplise，并放置到D盘中

（2）将下载的资源中的Hadoop-ecplise-plugin.jar 插件放到ecplise的插件目录中： D:\\ecplise\\plugins\\ 。然后开启ecplise。

（3）将Hadoop-2.7.1解压一份到D盘中，并配置相应的环境变量，并将%HADOOP_HOME%\\bin 文件加添加到Path环境中


（4）然后选在ecplise中配置hadoop插件：

A、Window---->show view -----> other ,在其中选中MapReduce tool

B: Window---->Perspective------>Open Perspective -----> othrer

C : Window ---->  Perferences ----> Hadoop Map/Reduce ,然后将刚刚解压的文件Hadoop文件选中

D、配置HDFS连接：该MapReduce view中创建一个新的MapReduce连接


当做完这些，我们就能在Package Exploer 中看到DFS，然后冲中可以看到HDFS上的文件：


2、进行MapReduce开发

（1）将hadoop-ecplise文件夹中的hadoopbin.zip进行解压，将会得到下列文件，并将这些文件放入到HADOOP_HOME\\bin目录下，然后将hadoop.dll文件放入到C:\\Window\\System32文件夹中


（2）从集群中下载： log4j.properties,core-site.xml,hdfs-site.xml,mapred-site.xml,yarn-site.xml 这五个文件。然后写出一个WordCount的例子，然后将这五个文件放入到src文件夹下：


（3）修改mapred-site.xml和yarn-site.xml文件

A、mapred-site.xml上添加一下几个keyvalue键值：

<property>
<name>mapred.remote.os</name>
<value>Linux</value>
</property>

<property>
<name>mapreduce.app-submission.cross-platform</name>
<value>true</value>
</property>
<property>
<name>mapreduce.application.classpath</name>
<value>/home/hadoop/hadoop/hadoop-2.7.1/etc/hadoop,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/common/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/common/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/hdfs/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/hdfs/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/mapreduce/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/mapreduce/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/yarn/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/yarn/lib/*</value>
</property>

 B、yarn-site.xml文件中添加一下参数： 

 

 

<property>
<name>yarn.application.classpath</name>
<value>/home/hadoop/hadoop/hadoop-2.7.1/etc/hadoop,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/common/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/common/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/hdfs/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/hdfs/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/mapreduce/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/mapreduce/lib/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/yarn/*,
        /home/hadoop/hadoop/hadoop-2.7.1/share/hadoop/yarn/lib/*</value>
</property>
 

 

这里需要解释一下，在Hadoop2.6之前，因为其源代码中适配了Linux操作系统中的环境变脸表示符号$，而当在window下使用这些代码是，因为两个系统之间的变量符是不一样的，所以会导致以下的错误
 

 

org.apache.hadoop.util.Shell$ExitCodeException: /bin/bash: line 0: fg: no job control 
在Hadoop2.6之前需要通过修改源代码后打jar包替换旧的Jar包文件，具体的流程请看下面这篇博客： 

 

http://www.aboutyun.com/thread-8498-1-1.html
 
 

在这里我们通过修改mapreduce.application.classpath 和 yarn.application.classpath这两个参数，将其修改成绝对路径，这样就不会出现上述的错误。
 

（3）开始WordCount函数：
 

 

package wc;
import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.record.compiler.JBoolean;

public class WCMapReduce 
	
	public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException
	
		Configuration conf=new Configuration();
		Job job=Job.getInstance(conf);
		job.setJobName("word count");
		job.setJarByClass(WCMapReduce.class);
		job.setJar("E:\\\\Ecplise\\\\WC.jar");
		//配置任务map和reduce类
		job.setMapperClass(WCMap.class);
		job.setReducerClass(WCReduce.class);
		//输出类型
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);
		//文件格式
		job.setInputFormatClass(TextInputFormat.class);
		job.setOutputFormatClass(TextOutputFormat.class);
		//设置输出输入路径
		FileInputFormat.addInputPath(job,new Path("hdfs://192.98.12.234:9000/Test/"));
		FileOutputFormat.setOutputPath(job, new Path("hdfs://192.98.12.234:9000/result"));
		//启动任务
		job.waitForCompletion(true);
	
	
	public static class WCMap extends Mapper<LongWritable, Text, Text, IntWritable>
	
		private static Text outKey=new Text();
		private static IntWritable outValue=new IntWritable(1);
		@Override
		protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, IntWritable>.Context context)
				throws IOException, InterruptedException 
			// TODO Auto-generated method stub
			String words=value.toString();
			StringTokenizer tokenizer=new StringTokenizer(words,"\\\\s");
			while(tokenizer.hasMoreTokens())
			
				String word=tokenizer.nextToken();
				outKey.set(word);
				context.write(outKey, outValue);
			
		
	
	
	public static class WCReduce extends Reducer<Text, IntWritable, Text, IntWritable>
	
		private static IntWritable outValue=new IntWritable(); 
		@Override
		protected void reduce(Text arg0, Iterable<IntWritable> arg1,
				Reducer<Text, IntWritable, Text, IntWritable>.Context arg2) throws IOException, InterruptedException 
			// TODO Auto-generated method stub
			int sum=0;
			for(IntWritable i:arg1)
			
				sum+=i.get();
			
			outValue.set(sum);
			arg2.write(arg0,outValue);
		
	



 

 

需要注意的是，因为这里实现的是远程提交方法，所以在远程提交时需要将任务的jar包发送到集群中，但是ecplise中并没有自带这种框架，因此需要先将jar打好在相应的文件中，然后在程序中，通过下行代码指定jar的位置。
 

 

job.setJar("E:\\\\Ecplise\\\\WC.jar");


 （4）配置提交任务的用户环境变量： 

 

如果windows上的用户名称和linux上启动集群的用户名称不相同时，则需要添加一个环境变量来实现任务的提交：
 


 
 

（5）运行结果
 

 

16/03/30 21:09:14 INFO client.RMProxy: Connecting to ResourceManager at hadoop1/192.98.12.234:8032
16/03/30 21:09:14 WARN mapreduce.JobResourceUploader: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
16/03/30 21:09:14 INFO input.FileInputFormat: Total input paths to process : 1
16/03/30 21:09:14 INFO mapreduce.JobSubmitter: number of splits:1
16/03/30 21:09:15 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1459331173846_0031
16/03/30 21:09:15 INFO impl.YarnClientImpl: Submitted application application_1459331173846_0031
16/03/30 21:09:15 INFO mapreduce.Job: The url to track the job: http://hadoop1:8088/proxy/application_1459331173846_0031/
16/03/30 21:09:15 INFO mapreduce.Job: Running job: job_1459331173846_0031
16/03/30 21:09:19 INFO mapreduce.Job: Job job_1459331173846_0031 running in uber mode : false
16/03/30 21:09:19 INFO mapreduce.Job:  map 0% reduce 0%
16/03/30 21:09:24 INFO mapreduce.Job:  map 100% reduce 0%
16/03/30 21:09:28 INFO mapreduce.Job:  map 100% reduce 100%
16/03/30 21:09:29 INFO mapreduce.Job: Job job_1459331173846_0031 completed successfully
16/03/30 21:09:29 INFO mapreduce.Job: Counters: 49
	File System Counters
		FILE: Number of bytes read=19942
		FILE: Number of bytes written=274843
		FILE: Number of read operations=0
		FILE: Number of large read operations=0
		FILE: Number of write operations=0
		HDFS: Number of bytes read=15533
		HDFS: Number of bytes written=15671
		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)=9860
		Total time spent by all reduces in occupied slots (ms)=2053
		Total time spent by all map tasks (ms)=2465
		Total time spent by all reduce tasks (ms)=2053
		Total vcore-seconds taken by all map tasks=2465
		Total vcore-seconds taken by all reduce tasks=2053
		Total megabyte-seconds taken by all map tasks=10096640
		Total megabyte-seconds taken by all reduce tasks=2102272
	Map-Reduce Framework
		Map input records=289
		Map output records=766
		Map output bytes=18404
		Map output materialized bytes=19942
		Input split bytes=104
		Combine input records=0
		Combine output records=0
		Reduce input groups=645
		Reduce shuffle bytes=19942
		Reduce input records=766
		Reduce output records=645
		Spilled Records=1532
		Shuffled Maps =1
		Failed Shuffles=0
		Merged Map outputs=1
		GC time elapsed (ms)=33
		CPU time spent (ms)=1070
		Physical memory (bytes) snapshot=457682944
		Virtual memory (bytes) snapshot=8013651968
		Total committed heap usage (bytes)=368050176
	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=15429
	File Output Format Counters 
		Bytes Written=15671
 

 

因为MapReduce任务在src文件下配置那5个文件时，会在本地种启动任务。当任务在本地执行的，任务的名称中就会出现local，而上述的任务名称中并没有出现local，因此成功将任务提交到了Linux 集群中
 

 


 
 


 
 


 
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