pwd # shows current directory
ls # lists files
cd dir # go into folder
cd .. # go back one folder
mkdir a # create folder
rm f # delete file
sudo # run command as admin

Enough to follow this guide.

4. Update Ubuntu

hljs bash

sudo apt update
sudo apt upgrade -y

5. Install Required Tools

hljs bash

sudo apt install -y wget curl vim unzip rsync

Explanation:

wget → download files
curl → send/receive data
vim → text editor
unzip → extract files
ssh → required by Hadoop
rsync → used internally by Hadoop

6. Install JDK (Java Development Kit)

Hadoop requires Java.

Install Java 11:

hljs bash

sudo apt install -y default-jdk

Check Java:

hljs bash

java -version

Find JAVA_HOME:

hljs bash

readlink -f $(which java) | sed "s:bin/java::"

You will get something like:

text

/usr/lib/jvm/java-11-openjdk-amd64/

Copy this path (you will paste it in .bashrc later).

7. Create a Dedicated Hadoop User

This is cleaner and avoids permission issues.

hljs bash

sudo adduser hadoop

Give a password (anything you like).

Add hadoop user to sudo:

hljs bash

sudo usermod -aG sudo hadoop

Switch to Hadoop user:

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su - hadoop

8. Enable SSH (Simple Setup)

Install SSH server:

hljs bash

sudo apt install openssh-client
sudo apt install openssh-server

Start SSH:

hljs bash

sudo service ssh start

Create SSH key (no password):

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ssh-keygen -t rsa

Add key to authorized keys:

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cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Fix permissions:

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chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

Test SSH:

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ssh localhost

If it logs in without asking password, SSH is set.

9. Download and Install Hadoop

hljs bash

su - hadoop

Download Hadoop 3.4.2 (latest as of now):

hljs bash

cd ~
wget https://downloads.apache.org/hadoop/common/hadoop-3.4.2/hadoop-3.4.2.tar.gz
tar -xzf hadoop-3.4.2.tar.gz
mv hadoop-3.4.2 hadoop

10. Add Environment Variables (Using nano as you requested)

Open .bashrc:

hljs bash

nano ~/.bashrc

Add these lines at the end of the file:

text

export JAVA_HOME=/usr/lib/jvm/java-21-openjdk-amd64
export HADOOP_HOME=/home/hadoop/hadoop
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin

Save nano:

Press Ctrl + O
Press Enter
Press Ctrl + X

Reload .bashrc:

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source ~/.bashrc

Check:

hljs bash

hadoop version

11. Understand Hadoop Folder Structure

Inside the Hadoop directory:

bin/ → Hadoop commands
sbin/ → start/stop scripts
etc/hadoop/ → configuration files
logs/ → logs generated later

All configuration happens inside etc/hadoop.

12. Configure Hadoop (Single Node Cluster)

Go into config directory:

hljs bash

cd $HADOOP_HOME/etc/hadoop

12.1 Edit hadoop-env.sh

hljs bash

nano hadoop-env.sh

Find the line:

text

export JAVA_HOME=

Replace with:

text

export JAVA_HOME=/usr/lib/jvm/java-21-openjdk-amd64

Save and exit.

12.2 core-site.xml

hljs bash

nano core-site.xml

Paste this:

text

<?xml version="1.0"?>
<configuration>
 <property>
 <name>fs.defaultFS</name>
 <value>hdfs://localhost:9000</value>
 </property>
 <property>
 <name>hadoop.tmp.dir</name>
 <value>/home/hadoop/hadoop_tmp</value>
 </property>
</configuration>

12.3 hdfs-site.xml

hljs bash

nano hdfs-site.xml

Paste:

text

<?xml version="1.0"?>
<configuration>
 <property>
 <name>dfs.replication</name>
 <value>1</value>
 </property>
 <property>
 <name>dfs.namenode.name.dir</name>
 <value>file:/home/hadoop/hadoop_tmp/hdfs/namenode</value>
 </property>
 <property>
 <name>dfs.datanode.data.dir</name>
 <value>file:/home/hadoop/hadoop_tmp/hdfs/datanode</value>
 </property>
</configuration>

12.4 mapred-site.xml

hljs bash

nano mapred-site.xml

Paste:

text

<?xml version="1.0"?>
<configuration>
 <property>
 <name>mapreduce.framework.name</name>
 <value>yarn</value>
 </property>
</configuration>

12.5 yarn-site.xml

hljs bash

nano yarn-site.xml

Paste:

text

<?xml version="1.0"?>
<configuration>
 <property>
 <name>yarn.nodemanager.aux-services</name>
 <value>mapreduce_shuffle</value>
 </property>
</configuration>

13. Create Hadoop Data Directories

hljs bash

mkdir -p ~/hadoop_tmp/hdfs/namenode
mkdir -p ~/hadoop_tmp/hdfs/datanode

14. Format NameNode

hljs bash

hdfs namenode -format

If you see "successfully formatted", it's correct.

15. Start Hadoop

Start HDFS:

hljs bash

start-dfs.sh

Start YARN:

hljs bash

start-yarn.sh

Check running processes:

hljs bash

jps

You should see:

NameNode
DataNode
SecondaryNameNode
ResourceManager
NodeManager

16. Access Hadoop on Windows Browser

Open Chrome/Edge on Windows:

NameNode:

text

http://localhost:9870/

YARN ResourceManager:

text

http://localhost:8088/

17. Test HDFS

hljs bash

hdfs dfs -mkdir /user/hadoop
echo "hello world" > test.txt
hdfs dfs -put test.txt /user/hadoop/
hdfs dfs -ls /user/hadoop/
hdfs dfs -cat /user/hadoop/test.txt

18. Stop Hadoop

hljs bash

stop-yarn.sh
stop-dfs.sh