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1. You have the latest JDK installed on your system as well. You can either get it from the official Oracle website (http://www.oracle.com/technetwork/java/javase/downloads/jdk-6u29-download-513648.html) or follow the advice given by your Linux distribution (e.g. some Debian based Linux distributions have JDK packaged as part of their extended set of packages). If your JDK is installed in a non-standard location, make sure to add the line below to the /etc/default/hadoop file

   No Format
   export JAVA_HOME=XXXX

2. Format the namenode

   No Format
   sudo -u hdfs hadoop namenode -format

3. Start the necessary Hadoop services. E.g. for the pseudo distributed Hadoop installation you can simply do:

   No Format
   for i in hadoop-namenode hadoop-datanode hadoop-jobtracker hadoop-tasktracker ; do sudo service $i start ; done

4. Once your basic cluster is up and running it is a good idea to create a home directory on the HDFS:

   No Format
   sudo -u hdfs hadoop fs -mkdir /user/$USER sudo -u hdfs hadoop fs -chown $USER /user/$USER

5. Enjoy your cluster

   No Format
   hadoop fs -lsr / hadoop jar /usr/lib/hadoop/hadoop-examples.jar pi 10 1000

6. If you are using Amazon AWS it is important the IP address in /etc/hostname matches the Private IP Address in the AWS Management Console. If the addresses do not match Map Reduce programs will not complete.

Running Hadoop Components

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