Hadoop Installation : ssh-keygen -t rsa -P ""

$ sudo add-apt-repository ppa:webupd8team/java
$ sudo apt-get update
$ sudo apt-get install oracle-java6-installer
$ sudo addgroup hadoop
$ sudo adduser —ingroup hadoop hduser
$ sudo apt-get install openssh-server
$ su - hduser
$ ssh-keygen -t rsa -P ""
$ cat $HOME/.ssh/id_rsa.pub >> $HOME/.ssh/authorized_keys
$ wget http://mirror.reverse.net/pub/apache/hadoop/common/hadoop-1.1.2/hadoop-1.1.2.tar.gz
$ cd /home/hduser
$ tar xzf hadoop-1.1.2.tar.gz
$ mv hadoop-1.1.2 hadoop
.bashrc
# Set Hadoop-related environment variables
export HADOOP_PREFIX=/home/hduser/hadoop
The next one points to the Java home directory. We need to make sure that it is pointing to Oracle Java
# Set JAVA_HOME (we will also configure JAVA_HOME directly for Hadoop later on)
export JAVA_HOME=/usr/lib/jvm/java-6-oracle
The last one is to update the PATH to include the Hadoop Home directory
# Add Hadoop bin/ directory to PATH
export PATH=$PATH:$HADOOP_PREFIX/bin
/home/hduser/hadoop/conf/hadoop-env.sh
export JAVA_HOME=/usr/lib/jvm/java-6-oracle
$ mkdir /home/hduser/tmp
/home/hduser/hadoop/conf/core-site.xml

hadoop.tmp.dir
/home/hduser/tmp
A base for other temporary directories.

fs.default.name
hdfs://localhost:54310
The name of the default file system. A URI whose
scheme and authority determine the FileSystem implementation. The
uri’s scheme determines the config property (fs.SCHEME.impl) naming
the FileSystem implementation class. The uri’s authority is used to
determine the host, port, etc. for a filesystem.
/home/hduser/hadoop/conf/mapred-site.xml

mapred.job.tracker
localhost:54311
The host and port that the MapReduce job tracker runs
at. If “local”, then jobs are run in-process as a single map
and reduce task.

/home/hduser/hadoop/conf/hdfs-site.xml

dfs.replication
1
Default block replication.
The actual number of replications can be specified when the file is created.
The default is used if replication is not specified in create time.

$ hadoop namenode -format
$ start-dfs.sh
$ start-mapred.sh
$ jps
$ hadoop jar hadoop-examples-1.1.2.jar pi 3 10
$ stop-dfs.sh
$ stop-mapred.sh