The current version of Hadoop is 2.5.1 and the steps mentioned here will assume that you use the same version. Login to your system using a Hadoop dedicated user and download the Hadoop 2.x bundle tar.gz file from the Apache archive:

wget https://archive.apache.org/dist/hadoop/core/hadoop-2.5.1/hadoop-2.5.1.tar.gz

You can use your home directory for the Hadoop installation (/home/<username>). If you want to use any of the system directories such as /opt or /usr for installation, you need to use the sudo option with the commands. For simplicity, we'll install Hadoop in the home directory of the user. The commands in this chapter assume that the username is hduser. You can replace hduser with the actual username. Move your Hadoop bundle to the user's home directory and extract the contents of the bundle file:

mv hadoop-2.5.1.tar.gz /home/hduser/
cd /home/hduser
tar -xzvf hadoop-2.5.1.tar.gz

Configure the Hadoop environment variables in /home/hduser/.bashrc (for Ubuntu) or /home/hduser/.bash_profile (for CentOS). Hadoop requires the HADOOP_PREFIX and home directory environment variables to be set before starting Hadoop services. HADOOP_PREFIX specifies the installation directory for Hadoop. We assume that you extracted the Hadoop bundle in the home folder of hduser.

Use the nano editor and append the following export commands to the end of the file:

export HADOOP_PREFIX="/home/hduser/hadoop-2.5.1/"
export PATH=$PATH:$HADOOP_PREFIX/bin
export PATH=$PATH:$HADOOP_PREFIX/sbin
export HADOOP_COMMON_HOME=${HADOOP_PREFIX}
export HADOOP_MAPRED_HOME=${HADOOP_PREFIX}
export HADOOP_HDFS_HOME=${HADOOP_PREFIX}
export YARN_HOME=${HADOOP_PREFIX}

After saving the file, you need to refresh the file using the source command:

source ~/.bashrc

Next, you need to configure the Hadoop site configuration files. There are four configuration files that you need to update. You can find these files in the $HADOOP_PREFIX/etc/Hadoop folder.

<property>
    <name>fs.defaultFS</name>
    <value>hdfs://localhost:8020</value>
    <final>true</final>
</property>

<property>
    <name>dfs.replication</name>
    <value>1</value>
</property>

<property>
    <name>dfs.namenode.name.dir</name>
    <value>file:///home/hduser/hadoop-2.5.1/hadoop_data/dfs/name</value>
</property>

<property>
    <name>dfs.datanode.data.dir</name>
    <value>file:///home/hduser/hadoop-2.5.1/hadoop_data/dfs/data</value>
</property>

cp /home/hduser/hadoop2.5.1/etc/Hadoop/mapred-site.xml.template /home/hduser/hadoop2.5.1/etc/Hadoop/mapred-site.xml

<property>
  <name>mapreduce.framework.name</name>
  <value>yarn</value>
</property>

<property>
    <name>yarn.resourcemanager.address</name>
    <value>localhost:8032</value>
</property>

<property>
    <name>yarn.resourcemanager.scheduler.address</name>
    <value>localhost:8030</value>
</property>

<property>
    <name>yarn.resourcemanager.resource-tracker.address</name>
    <value>localhost:8031</value>
</property>

<property>
    <name>yarn.resourcemanager.admin.address</name>
    <value>localhost:8033</value>
</property>

<property>
    <name>yarn.resourcemanager.webapp.address</name>
    <value>localhost:8088</value>
</property>

<property>
    <name>yarn.nodemanager.aux-services</name>
    <value>mapreduce_shuffle</value>
</property>

<property>
    <name>yarn.nodemanager.aux-services.mapreduce_shuffle.class</name>
    <value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>

<property>
    <name>yarn.resourcemanager.scheduler.class</name>
    <value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler</value>
</property>

After configuring Hadoop files, you need to format the HDFS using the namenode format command. Before executing the format command, make sure that the dfs.namenode.name.dir directory specified in the hdfs-site.xml file does not exist. This directory is created by the namenode format command. Execute the following command to format NameNode:

hdfs namenode –format

After executing the preceding command, make sure that there's no exception on the console and that the namenode directory is created.

Start the Hadoop services using Hadoop 2 Scripts in the /home/hduser/hadoop-2.5.1/sbin/ directory. For a single node installation, all the daemons will run on a single system. Use the following commands to start the services one by one.

Execute the jps command and ensure that all Hadoop daemons are running. You can also verify the status of your cluster through the web interface for HDFS-NameNode and YARN-ResourceManager.

You need to replace <NameNodeHost> and <ResourceManagerHost> with localhost for single node installation such as http://localhost:8088/.