Mac下Eclipse提交任務到Hadoop集羣

搭建Hadoop集羣: VirtualBox+Ubuntu 14.04+Hadoop2.6.0

搭建好集羣后, 在Mac下安裝Eclipse並鏈接Hadoop集羣

1. 訪問集羣

1.1. 修改Mac的hosts

添加Master的IP到Mac的hosts

##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1    localhost
255.255.255.255    broadcasthost
::1             localhost

192.168.56.101  Master # 添加Master的IP

1.2 訪問集羣

Master下, 啓動集羣
Mac下, 打開http://master:50070/
可以成功訪問, 看到集羣的信息, 就能夠了

2. 下載安裝Eclipse

Eclipse IDE for Java Developers

http://www.eclipse.org/downloads/package...

3. 配置Eclipse

3.1 配置Hadoop-Eclipse-Plugin

3.1.1 下載Hadoop-Eclipse-Plugin

可下載 Github 上的 hadoop2x-eclipse-plugin（備用下載地址：http://pan.baidu.com/s/1i4ikIoP）

3.1.2 安裝Hadoop-Eclipse-Plugin

在Applications中找個Eclise, 右鍵, Show Package Contents

將插件複製到plugins目錄下, 而後從新打開Eclipse就能夠了

3.2 鏈接Hadoop集羣

3.2.1 配置Hadoop安裝目錄

將Hadoop安裝包解壓到任何目錄, 不用作任何配置, 而後在Eclipse中指向該目錄便可

3.2.2 配置集羣地址

點擊右上角的加號

添加Map/Reduce視圖

選擇Map/Reduce Locations, 而後右鍵, 選擇New Hadoop location

須要改Location name, Host, DFS Master下的Port, User name ( Master會引用Mac中的hosts配置的IP ), 完成後, Finish

3.2.3 查看HDFS

查看是否能夠直接訪問HDFS

4. 集羣中運行WordCount

4.1 建立項目

File -> New -> Other -> Map/Reduce Project

輸入項目名: WordCount, 而後點擊, Finish

4.2 建立類

建立一個類, 報名org.apache.hadoop.examples, 類名: WordCount

4.3 WordCount代碼

複製下面的代碼到WordCount.java中

package org.apache.hadoop.examples;
 
import java.io.IOException;
import java.util.StringTokenizer;
 
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
 
public class WordCount {
 
  public static class TokenizerMapper 
       extends Mapper<Object, Text, Text, IntWritable>{
 
    private final static IntWritable one = new IntWritable(1);
    private Text word = new Text();
 
    public void map(Object key, Text value, Context context
                    ) throws IOException, InterruptedException {
      StringTokenizer itr = new StringTokenizer(value.toString());
      while (itr.hasMoreTokens()) {
        word.set(itr.nextToken());
        context.write(word, one);
      }
    }
  }
 
  public static class IntSumReducer 
       extends Reducer<Text,IntWritable,Text,IntWritable> {
    private IntWritable result = new IntWritable();
 
    public void reduce(Text key, Iterable<IntWritable> values, 
                       Context context
                       ) throws IOException, InterruptedException {
      int sum = 0;
      for (IntWritable val : values) {
        sum += val.get();
      }
      result.set(sum);
      context.write(key, result);
    }
  }
 
  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
    if (otherArgs.length != 2) {
      System.err.println("Usage: wordcount <in> <out>");
      System.exit(2);
    }
    Job job = new Job(conf, "word count");
    job.setJarByClass(WordCount.class);
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
    FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}

4.4 配置Hadoop參數

將全部修改過的配置文件和log4j.properties, 複製到src目標下

這裏我複製了slaves, core-site.xml, hdfs-site.xml, mapred-site.xml, yarn-site.xml

4.4 配置HDFS輸入輸出路徑

鼠標移動到WordCount.java上, 右鍵, Run As, Java Application

此時, 程序不會正常運行. 再次右鍵, Run As, 選擇Run Configurations

填入輸入輸出路徑 (空格分割)

配置完成後點擊, Run. 此時會出現, Permission denied

5. 運行中出現的問題

5.1 Permission denied

沒有權限訪問HDFS

# 假設Mac的用戶名爲hadoop
groupadd supergroup # 添加supergroup組
useradd -g supergroup hadoop # 添加hadoop用戶到supergroup組

# 修改hadoop集羣中hdfs文件的組權限, 使屬於supergroup組的全部用戶都有讀寫權限
hadoop fs -chmod 777 /

6. 查看Hadoop源碼

6.1 下載源碼

http://apache.claz.org/hadoop/common/had...

6.2 連接源碼

右上角的搜索框中, 搜索Open Type

輸入NameNode, 選擇NameNode, 發現看不了源碼

點擊Attach Source -> External location -> External Floder

參考資料

使用Eclipse編譯運行MapReduce程序 Hadoop2.6.0_Ubuntu/CentOS