How to install Hadoop?

To install Hadoop, follow these steps:

1. Prerequisites:

   • Ensure you have Java installed (Java 8 or later).
   • Set the JAVA_HOME environment variable.

2. Download Hadoop:

   wget https://downloads.apache.org/hadoop/common/hadoop-x.y.z/hadoop-x.y.z.tar.gz
   

   Replace x.y.z with the desired version number.

3. Extract the downloaded file:

   tar -xzvf hadoop-x.y.z.tar.gz
   

4. Move to the desired directory:

   mv hadoop-x.y.z /usr/local/hadoop
   

5. Set environment variables: Add the following lines to your .bashrc or .bash_profile:

   export HADOOP_HOME=/usr/local/hadoop
   export PATH=$PATH:$HADOOP_HOME/bin
   export JAVA_HOME=/path/to/java
   

6. Source the profile:

   source ~/.bashrc
   

7. Configure Hadoop: Edit the configuration files in the $HADOOP_HOME/etc/hadoop directory:

   • core-site.xml
   • hdfs-site.xml
   • mapred-site.xml
   • yarn-site.xml

8. Format the NameNode:

   hdfs namenode -format
   

9. Start Hadoop:

   start-dfs.sh
   start-yarn.sh
   

10. Verify Installation: Check if Hadoop is running:

    jps
    

This should show the Hadoop daemons running, such as NameNode, DataNode, ResourceManager, and NodeManager.