Changes between Version 17 and Version 18 of Hadoop_Lab5

Timestamp:

Apr 26, 2010, 6:16:48 PM (16 years ago)

Author:

waue

Comment:

--

Hadoop_Lab5

@@ -1 @@
-[[WikiInclude(waue/2009/0617)]]
+[[PageOutline]]
+{{{
+#!html
+<div style="text-align: center;"><big
+ style="font-weight: bold;"><big><big> hadoop 0.20 程式開發 </big></big></big></div>
+<div style="text-align: center;"> <big>eclipse plugin + Makefile</big> </div>
+}}}
+ = 零. 前言 =
+ * 開發hadoop 需要用到許多的物件導向語法，包括繼承關係、介面類別，而且需要匯入正確的classpath，否則寫hadoop程式只是打字練習...
+ * 用類 vim 來處理這種複雜的程式，有可能會變成一場惡夢，因此用eclipse開發，搭配mapreduce-plugin會事半功倍。
+ * 若繼承練習一的系統，可以直接跳到'''二、 建立專案 ''' 開始
+
+ == 0.1 環境說明 == 
+ * ubuntu 8.10
+ * sun-java-6
+ * eclipse 3.3.2
+ * hadoop 0.20.2
+ == 0.2 目錄說明 == 
+ * 使用者：waue
+ * 使用者家目錄： /home/hadooper
+ * 專案目錄 ： /home/hadooper/workspace
+ * hadoop目錄： /opt/hadoop
+ = 一、安裝 =
+
+安裝的部份沒必要都一模一樣，僅提供參考，反正只要安裝好java , hadoop , eclipse，並清楚自己的路徑就可以了
+
+ == 1.1. 安裝java ==
+ 
+首先安裝java 基本套件
+ 
+{{{
+$ sudo apt-get install java-common sun-java6-bin sun-java6-jdk sun-java6-jre
+}}}
+
+ == 1.1.1. 安裝sun-java6-doc ==
+ 
+ 1 將javadoc (jdk-6u10-docs.zip) 下載下來
+ [https://cds.sun.com/is-bin/INTERSHOP.enfinity/WFS/CDS-CDS_Developer-Site/en_US/-/USD/ViewProductDetail-Start?ProductRef=jdk-6u10-docs-oth-JPR@CDS-CDS_Developer 下載點]
+[[Image(wiki:waue:2009:0617:1-1.png)]]
+[[Image(wiki:0428Hadoop_Lab1:hadoop_administration.png)]]
+ 
+ 2 下載完後將檔案放在 /tmp/ 下
+
+ 3 執行
+ 
+{{{
+$ sudo apt-get install sun-java6-doc
+}}}
+
+ == 1.2. ssh 安裝設定 ==
+
+{{{
+$ apt-get install ssh 
+$ ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
+$ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
+$ ssh localhost
+}}}
+
+執行ssh localhost 沒有出現詢問密碼的訊息則無誤
+
+ == 1.3. 安裝hadoop ==
+
+安裝hadoop0.20到/opt/並取目錄名為hadoop
+
+{{{
+$ cd ~
+$ wget http://apache.ntu.edu.tw/hadoop/core/hadoop-0.20.2/hadoop-0.20.2.tar.gz
+$ tar zxvf hadoop-0.20.2.tar.gz
+$ sudo mv hadoop-0.20.2 /opt/
+$ sudo chown -R waue:waue /opt/hadoop-0.20.2
+$ sudo ln -sf /opt/hadoop-0.20.2 /opt/hadoop
+}}}
+
+ * 編輯 /opt/hadoop/conf/hadoop-env.sh
+
+{{{
+#!sh
+export JAVA_HOME=/usr/lib/jvm/java-6-sun
+export HADOOP_HOME=/opt/hadoop
+export PATH=$PATH:/opt/hadoop/bin
+}}}
+
+ * 編輯 /opt/hadoop/conf/core-site.xml
+
+{{{
+#!sh
+<configuration>
+  <property>
+    <name>fs.default.name</name>
+    <value>hdfs://localhost:9000</value>
+  </property>
+  <property>
+    <name>hadoop.tmp.dir</name>
+    <value>/tmp/hadoop/hadoop-${user.name}</value>
+  </property>
+</configuration>
+
+}}}
+
+ * 編輯 /opt/hadoop/conf/hdfs-site.xml
+
+{{{
+#!sh
+<configuration>
+  <property>
+    <name>dfs.replication</name>
+    <value>1</value>
+  </property>
+</configuration>
+}}}
+
+ * 編輯 /opt/hadoop/conf/mapred-site.xml
+
+{{{
+#!sh
+<configuration>
+  <property>
+    <name>mapred.job.tracker</name>
+    <value>localhost:9001</value>
+  </property>
+</configuration>
+}}}
+
+ * 啟動
+{{{
+$ cd /opt/hadoop
+$ source /opt/hadoop/conf/hadoop-env.sh
+$ hadoop namenode -format
+$ start-all.sh
+$ hadoop fs -put conf input
+$ hadoop fs -ls 
+}}}
+
+ * 沒有錯誤訊息則代表無誤
+
+ == 1.4. 安裝eclipse ==
+ 
+ * 在此提供兩個方法來下載檔案
+   * 方法一：下載 [http://www.eclipse.org/downloads/download.php?file=/eclipse/downloads/drops/R-3.4.2-200902111700/eclipse-SDK-3.4.2-linux-gtk.tar.gz eclipse SDK 3.4.2 Classic]，並且放這檔案到家目錄
+   * 方法二：貼上指令
+{{{
+$ cd ~
+$ wget http://ftp.cs.pu.edu.tw/pub/eclipse/eclipse/downloads/drops/R-3.4.2-200902111700/eclipse-SDK-3.4.2-linux-gtk.tar.gz
+}}}
+
+ * eclipse 檔已下載到家目錄後，執行下面指令：
+ 
+{{{
+$ cd ~
+$ tar -zxvf eclipse-SDK-3.4.2-linux-gtk.tar.gz
+$ sudo mv eclipse /opt
+$ sudo ln -sf /opt/eclipse/eclipse /usr/local/bin/
+
+}}}
+
+ = 二、 建立專案 = 
+
+== 2.1 安裝hadoop 的 eclipse plugin ==
+
+ * 匯入hadoop 0.20.2 eclipse plugin 
+ 
+{{{
+$ cd /opt/hadoop
+$ sudo cp /opt/hadoop/contrib/eclipse-plugin/hadoop-0.20.2-eclipse-plugin.jar /opt/eclipse/plugins
+}}}
+
+{{{
+$ sudo vim /opt/eclipse/eclipse.ini
+}}}
+
+ * 可斟酌參考eclipse.ini內容（非必要）
+ 
+{{{
+#!sh
+-startup
+plugins/org.eclipse.equinox.launcher_1.0.101.R34x_v20081125.jar
+--launcher.library
+plugins/org.eclipse.equinox.launcher.gtk.linux.x86_1.0.101.R34x_v20080805
+-showsplash
+org.eclipse.platform
+--launcher.XXMaxPermSize
+512m
+-vmargs
+-Xms40m
+-Xmx512m
+}}}
+
+== 2.2 開啟eclipse ==
+
+ * 打開eclipse 
+ 
+{{{
+$ eclipse &
+}}}
+
+一開始會出現問你要將工作目錄放在哪裡：在這我們用預設值
+
+[[Image(wiki:waue:2009:0617:2-1.png)]] 
+
+-------
+
+'''PS: 之後的說明則是在eclipse 上的介面操作'''
+
+-------
+
+== 2.3 選擇視野 ==
+
+|| window -> || open pers.. -> || other.. -> || map/reduce|| 
+
+[[Image(wiki:waue:2009:0617:win-open-other.png)]] 
+
+-------
+
+設定要用 Map/Reduce 的視野
+[[Image(wiki:waue:2009:0617:2-2.png)]] 
+
+---------
+
+使用 Map/Reduce 的視野後的介面呈現
+[[Image(wiki:waue:2009:0617:2-3.png)]] 
+
+--------
+
+== 2.4 建立專案 ==
+
+ || file ->  || new ->  || project ->  || Map/Reduce ->  || Map/Reduce Project -> ||  next || 
+[[Image(wiki:waue:2009:0617:file-new-project.png)]]
+
+--------
+
+建立mapreduce專案(1)
+
+[[Image(wiki:waue:2009:0617:2-4.png)]] 
+
+-----------
+
+建立mapreduce專案的(2)
+{{{
+#!sh
+project name-> 輸入 : icas (隨意)
+use default hadoop -> Configur Hadoop install... -> 輸入： "/opt/hadoop" -> ok
+Finish
+}}}
+
+[[Image(wiki:waue:2009:0617:2-4-2.png)]]
+
+
+--------------
+
+== 2.5 設定專案 ==
+
+由於剛剛建立了icas這個專案，因此eclipse已經建立了新的專案，出現在左邊視窗，右鍵點選該資料夾，並選properties
+
+--------------
+
+ Step1. 右鍵點選project的properties做細部設定
+
+[[Image(wiki:waue:2009:0617:2-5.png)]]
+
+----------
+
+ Step2. 進入專案的細部設定頁
+
+hadoop的javadoc的設定(1)
+[[Image(wiki:waue:2009:0617:Image(2-5-1.png)]]
+
+ * java Build Path -> Libraries -> hadoop-0.20.2-ant.jar
+ * java Build Path -> Libraries -> hadoop-0.20.2-core.jar 
+ * java Build Path -> Libraries ->  hadoop-0.20.2-tools.jar
+   * 以 hadoop-0.20.2-core.jar 的設定內容如下，其他依此類推
+   
+{{{
+#!sh
+source ...-> 輸入：/opt/opt/hadoop-0.20.2/src/core
+javadoc ...-> 輸入：file:/opt/hadoop/docs/api/
+}}}
+
+------------
+ Step3. hadoop的javadoc的設定完後(2)
+[[Image(wiki:waue:2009:0617:Image(2-5-2.png)]]
+
+------------
+ Step4. java本身的javadoc的設定(3)
+ 
+ * javadoc location -> 輸入：file:/usr/lib/jvm/java-6-sun/docs/api/
+ 
+[[Image(wiki:waue:2009:0617:2-5-3.png)]]
+
+-----
+設定完後回到eclipse 主視窗
+
+
+== 2.6 連接hadoop server ==
+
+--------
+ Step1. 視窗右下角黃色大象圖示"Map/Reduce Locations tag" -> 點選齒輪右邊的藍色大象圖示：
+[[Image(wiki:waue:2009:0617:2-6.png)]]
+
+-------------
+ Step2. 進行eclipse 與 hadoop 間的設定(2)
+[[Image(wiki:waue:2009:0617:2-6-1.png)]]
+
+{{{
+#!sh
+Location Name -> 輸入：hadoop  (隨意)
+Map/Reduce Master -> Host-> 輸入：localhost 
+Map/Reduce Master -> Port-> 輸入：9001 
+DFS Master -> Host-> 輸入：9000
+Finish
+}}}
+----------------
+
+設定完後，可以看到下方多了一隻藍色大象，左方展開資料夾也可以秀出在hdfs內的檔案結構
+[[Image(wiki:waue:2009:0617:2-6-2.png)]]
+-------------
+
+ = 三、 撰寫範例程式 =
+
+ * 之前在eclipse上已經開了個專案icas，因此這個目錄在：
+   * /home/hadooper/workspace/icas
+ * 在這個目錄內有兩個資料夾： 
+   * src ： 用來裝程式原始碼 
+   * bin ： 用來裝編譯後的class檔
+ * 如此一來原始碼和編譯檔就不會混在一起，對之後產生jar檔會很有幫助
+ * 在這我們編輯一個範例程式 : WordCount 
+
+ == 3.1 mapper.java ==
+ 
+ 1. new
+ 
+ || File ->  || new ->  || mapper || 
+[[Image(wiki:waue:2009:0617:file-new-mapper.png)]]
+
+-----------
+
+ 2. create
+ 
+[[Image(wiki:waue:2009:0617:3-1.png)]]
+{{{
+#!sh
+source folder-> 輸入： icas/src
+Package : Sample
+Name -> : mapper
+}}}
+----------
+
+ 3. modify
+ 
+{{{
+#!java
+package Sample;
+
+import java.io.IOException;
+import java.util.StringTokenizer;
+
+import org.apache.hadoop.io.IntWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.Mapper;
+
+public class mapper 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);
+                }
+        }
+}
+}}}
+
+建立mapper.java後，貼入程式碼
+[[Image(wiki:waue:2009:0617:3-2.png)]]
+
+------------
+
+== 3.2 reducer.java ==
+
+ 1. new
+
+ * File -> new -> reducer
+[[Image(wiki:waue:2009:0617:file-new-reducer.png)]]
+
+-------
+ 2. create
+[[Image(wiki:waue:2009:0617:3-3.png)]]
+
+{{{
+#!sh
+source folder-> 輸入： icas/src
+Package : Sample
+Name -> : reducer
+}}}
+
+-----------
+
+ 3. modify 
+ 
+{{{
+#!java
+package Sample;
+
+import java.io.IOException;
+
+import org.apache.hadoop.io.IntWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapreduce.Reducer;
+
+public class reducer 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);
+        }
+}
+}}}
+
+ * File -> new -> Map/Reduce Driver
+[[Image(wiki:waue:2009:0617:file-new-mr-driver.png)]]
+----------
+
+== 3.3 WordCount.java (main function) ==
+
+ 1. new
+
+建立WordCount.java，此檔用來驅動mapper 與 reducer，因此選擇 Map/Reduce Driver
+[[Image(wiki:waue:2009:0617:3-4.png)]]
+------------
+
+ 2. create
+
+{{{
+#!sh
+source folder-> 輸入： icas/src
+Package : Sample
+Name -> : WordCount.java
+}}}
+
+-------
+ 3. modify
+
+{{{
+#!java
+package Sample;
+
+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.lib.input.FileInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+import org.apache.hadoop.util.GenericOptionsParser;
+
+public class WordCount {
+
+        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(mapper.class);
+
+                job.setCombinerClass(reducer.class);
+                job.setReducerClass(reducer.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);
+        }
+}
+}}}
+
+三個檔完成後並存檔後，整個程式建立完成
+[[Image(wiki:waue:2009:0617:3-5.png)]]
+
+-------
+
+ * 三個檔都存檔後，可以看到icas專案下的src，bin都有檔案產生，我們用指令來check
+ 
+{{{
+$ cd workspace/icas
+$ ls src/Sample/
+mapper.java  reducer.java  WordCount.java
+$ ls bin/Sample/
+mapper.class  reducer.class  WordCount.class
+}}}
+
+ = 四、測試範例程式 =
+ 
+ * 右鍵點選WordCount.java -> run as -> run on Hadoop 
+   
+[[Image(wiki:waue:2009:0617:run-on-hadoop.png)]]
+
+
+
+= 五、結論 =
+
+ * 搭配eclipse ，我們可以更有效率的開發hadoop
+ * hadoop 0.20 與之前的版本api以及設定都有些改變，因此hadoop 環境的設定，需要看[http://hadoop.apache.org/core/docs/r0.20.2/quickstart.html hadoop 0.20 的quickstart]； 而如何使用 [http://hadoop.apache.org/core/docs/r0.20.2/api/ hadoop 0.20] 的api，則可以看 /opt/hadoop/src/example/ 裡面的程式碼來提供初步的構想