2008-11-04

• Devaraj Das 來訪
  • 09:30 - 10:30 拜會中心主任
  • 11:00 - 12:30 Public Talk Session: "Introduction to Hadoop and Cloud Computing" @ 北群多媒體
  • 14:00 - 17:00 Hands-on Labs (1): "Basics of DFS commands + How to develop MapReduce program using Hadoop?" @ 北群多媒體

• Hadoop Hands-on Labs (1)
  • download hadoop-0.18.2

    $ wget http://ftp.twaren.net/Unix/Web/apache/hadoop/core/hadoop-0.18.2/hadoop-0.18.2.tar.gz
    $ tar zxvf hadoop-0.18.2.tar.gz
    

  • [注意] 需要 JAVA_HOME 環境變數才能執行 hadoop namenode

    $ echo "export JAVA_HOME=/usr/lib/jvm/java-6-sun/jre" >> ~/.bash_profile
    $ cd hadoop-0.18.2
    ~/hadoop-0.18.2$ bin/hadoop namenode -format
    

  • 編輯 conf/hadoop-site.xml 在 configuration 那一段加入以下設定

    <configuration>
    <property>
      <name>fs.default.name</name>
      <value>localhost:5000</value>
     </property>
    </configuration>
    

  • 用 bin/hadoop namenode 啟動 namenode

    ~/hadoop-0.18.2$ bin/hadoop namenode 
    <ctrl-C> and come out
    

  • 執行 bin/start-dfs.sh

    ~/hadoop-0.18.2$ bin/start-dfs.sh
    starting namenode, logging to /home/jazz/hadoop-0.18.2/bin/../logs/hadoop-jazz-namenode-hadoop.out
    The authenticity of host 'localhost (127.0.0.1)' can't be established.
    RSA key fingerprint is 70:3f:8b:f2:b9:a8:de:ea:90:f4:bf:ce:cb:85:7a:eb.
    Are you sure you want to continue connecting (yes/no)? yes
    localhost: Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
    

  • 從這邊的訊息可以知道 Hadoop 會用 SSH 進行內部連線，因此需要做 SSH Key exchange

    ~$ ssh-keygen
    ~$ cp .ssh/id_rsa.pub .ssh/authorized_keys
    

  • 如果遇到 JAVA_HOME 的問題，可以改用手動的方式啟動 DFS 服務

    ~/hadoop-0.18.2$ bin/hadoop datanode
    ~/hadoop-0.18.2$ bin/hadoop-daemon.sh start datanode
    

  • ​http://localhost:50070/