How to Install Hadoop?

Hadoop Installation

Environment required for Hadoop: The production environment of Hadoop is UNIX, but it can also be used in Windows using Cygwin. Java 1.6 or above is needed to run Map Reduce Programs. For Hadoop installation from tar ball on the UNIX environment you need

  1. Java Installation
  2. SSH installation
  3. Hadoop Installation and File Configuration

1) Java Installation

Step 1. Type “java -version” in prompt to find if the java is installed or not. If not then download java from JavaSE Upgrade . The tar filejdk-7u71-linux-x64.tar.gz will be downloaded to your system.

Step 2. Extract the file using the below command

#tar zxf jdk-7u71-linux-x64.tar.gz

Step 3. To make java available for all the users of UNIX move the file to /usr/local and set the path. In the prompt switch to root user and then type the command below to move the jdk to /usr/lib.

  # mv jdk1.7.0_71 /usr/lib/`

Now in ~/.bashrc file add the following commands to set up the path.

 # export JAVA_HOME=/usr/lib/jdk1.7.0_71  
 # export PATH=PATH:$JAVA_HOME/bin

Now, you can check the installation by typing “java -version” in the prompt.

2) SSH Installation

SSH is used to interact with the master and slaves computer without any prompt for password. First of all create a Hadoop user on the master and slave systems

# useradd hadoop  
# passwd Hadoop  

To map the nodes open the hosts file present in /etc/ folder on all the machines and put the ip address along with their host name.

# vi /etc/hosts

Enter the lines below

190.12.1.114 hadoop-master
190.12.1.121 hadoop-salve-one
190.12.1.143 hadoop-slave-two

Set up SSH key in every node so that they can communicate among themselves without password. Commands for the same are:

# su hadoop   
$ ssh-keygen -t rsa   
$ ssh-copy-id -i ~/.ssh/id_rsa.pub tutorialspoint@hadoop-master   
$ ssh-copy-id -i ~/.ssh/id_rsa.pub hadoop_tp1@hadoop-slave-1   
$ ssh-copy-id -i ~/.ssh/id_rsa.pub hadoop_tp2@hadoop-slave-2   
$ chmod 0600 ~/.ssh/authorized_keys   
$ exit

export JAVA_HOME=/usr/lib/jvm/jdk/jdk1.7.0_71
2) In core-site.xml add following between configuration tabs,

fs.default.name hdfs://hadoop-master:9000 dfs.permissions false 3) In hdfs-site.xmladd following between configuration tabs, dfs.data.dir usr/hadoop/dfs/name/data true dfs.name.dir usr/hadoop/dfs/name true dfs.replication 1 4) Open the Mapred-site.xml and make the change as shown below mapred.job.tracker hadoop-master:9001 5) Finally, update your $HOME/.bahsrc
cd $HOME  
vi .bashrc  
Append following lines in the end and save and exit  
#Hadoop variables   
export JAVA_HOME=/usr/lib/jvm/jdk/jdk1.7.0_71  
export HADOOP_INSTALL=/usr/hadoop  
export PATH=$PATH:$HADOOP_INSTALL/bin   
export PATH=$PATH:$HADOOP_INSTALL/sbin  
export HADOOP_MAPRED_HOME=$HADOOP_INSTALL   
export HADOOP_COMMON_HOME=$HADOOP_INSTALL  
export HADOOP_HDFS_HOME=$HADOOP_INSTALL   
export YARN_HOME=$HADOOP_INSTALL  

On the slave machine install Hadoop using the command below

# su hadoop   
$ cd /opt/hadoop   
$ scp -r hadoop hadoop-slave-one:/usr/hadoop   
$ scp -r hadoop hadoop-slave-two:/usr/Hadoop  

Configure master node and slave node

$ vi etc/hadoop/masters  
hadoop-master  
  
$ vi etc/hadoop/slaves  
hadoop-slave-one   
hadoop-slave-two  

After this format the name node and start all the deamons

# su hadoop   
$ cd /usr/hadoop   
$ bin/hadoop namenode -format  
  
$ cd $HADOOP_HOME/sbin  
$ start-all.sh  

The easiest step is the usage of cloudera as it comes with all the stuffs pre-installed which can be downloaded from http://content.udacity-data.com/courses/ud617/Cloudera-Udacity-Training-VM-4.1.1.c.zip