Eclipse遠端提交MapReduce任務到Hadoop叢集
一、介紹
以前寫完MapReduce任務以後總是打包上傳到Hadoop叢集,然後通過shell命令去啟動任務,然後在各個節點上去檢視Log日誌檔案,後來為了提高開發效率,需要找到通過Ecplise直接將MaprReduce任務直接提交到Hadoop叢集中。該章節講述使用者如何從Eclipse的壓縮包最終完成Eclipse提價任務給MapReduce叢集。
二、詳解
1、安裝Eclipse,安裝hadoop外掛
(1)首先下載Eclipse的壓縮包,然後可以從這裡下載hadoop 2.7.1的ecplise外掛和其他一些搭建環境中所需要的檔案,然後解壓ecplise,並放置到D盤中
(2)將下載的資源中的Hadoop-ecplise-plugin.jar 外掛放到ecplise的外掛目錄中: D:\ecplise\plugins\ 。然後開啟ecplise。
(3)將Hadoop-2.7.1解壓一份到D盤中,並配置相應的環境變數,並將%HADOOP_HOME%\bin 檔案加新增到Path環境中
(4)然後選在ecplise中配置hadoop外掛:
A、Window---->show view -----> other ,在其中選中MapReduce tool
B: Window---->Perspective------>Open Perspective -----> othrer
C : Window ----> Perferences ----> Hadoop Map/Reduce ,然後將剛剛解壓的檔案Hadoop檔案選中
D、配置HDFS連線:該MapReduce view中建立一個新的MapReduce連線
當做完這些,我們就能在Package Exploer 中看到DFS,然後衝中可以看到HDFS上的檔案:
2、進行MapReduce開發
(1)將hadoop-ecplise資料夾中的hadoopbin.zip進行解壓,將會得到下列檔案,並將這些檔案放入到HADOOP_HOME\bin目錄下,然後將hadoop.dll檔案放入到C:\Window\System32資料夾中
(2)從叢集中下載: log4j.properties,core-site.xml,hdfs-site.xml,mapred-site.xml,yarn-site.xml 這五個檔案。然後寫出一個WordCount的例子,然後將這五個檔案放入到src資料夾下:
(3)修改mapred-site.xml和yarn-site.xml檔案
A、mapred-site.xml上新增一下幾個keyvalue鍵值:
<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檔案中新增一下引數:
<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>
這裡需要解釋一下,在Hadoop2.6之前,因為其原始碼中適配了Linux作業系統中的環境變臉表示符號$,而當在window下使用這些程式碼是,因為兩個系統之間的變數符是不一樣的,所以會導致以下的錯誤
org.apache.hadoop.util.Shell$ExitCodeException: /bin/bash: line 0: fg: no job control
在Hadoop2.6之前需要通過修改原始碼後打jar包替換舊的Jar包檔案,具體的流程請看下面這篇部落格:
在這裡我們通過修改mapreduce.application.classpath 和 yarn.application.classpath這兩個引數,將其修改成絕對路徑,這樣就不會出現上述的錯誤。
(3)開始WordCount函式:
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");
//配置任務map和reduce類
job.setMapperClass(WCMap.class);
job.setReducerClass(WCReduce.class);
//輸出型別
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
//檔案格式
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
//設定輸出輸入路徑
FileInputFormat.addInputPath(job,new Path("hdfs://192.98.12.234:9000/Test/"));
FileOutputFormat.setOutputPath(job, new Path("hdfs://192.98.12.234:9000/result"));
//啟動任務
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,因為這裡實現的是遠端提交方法,所以在遠端提交時需要將任務的jar包傳送到叢集中,但是ecplise中並沒有自帶這種框架,因此需要先將jar打好在相應的檔案中,然後在程式中,通過下行程式碼指定jar的位置。
job.setJar("E:\\Ecplise\\WC.jar");
(4)配置提交任務的使用者環境變數:
如果windows上的使用者名稱稱和linux上啟動叢集的使用者名稱稱不相同時,則需要新增一個環境變數來實現任務的提交:
(5)執行結果
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
因為MapReduce任務在src檔案下配置那5個檔案時,會在本地種啟動任務。當任務在本地執行的,任務的名稱中就會出現local,而上述的任務名稱中並沒有出現local,因此成功將任務提交到了Linux 叢集中