Knowledgebase

Introduction

Apache Hadoop is an open-source software framework used to store, manage and process large datasets for various big data computing applications running under clustered systems. It is Java-based and uses Hadoop Distributed File System (HDFS) to store its data and process data using MapReduce. In this article, you will learn how ro install and configure Apache Hadoop on Ubuntu 20.04.

Prerequisites

• Deploy a fully updated Rcs Ubuntu 20.04 Server.
• Create a non-root user with sudo access.

1. Install Java

Install the latest version of Java.

$ sudo apt install default-jdk default-jre -y

Verify the installed version of Java.

$ java -version

2. Create Hadoop User and Configure Password-less SSH

Add a new user hadoop.

$ sudo adduser hadoop

Add the hadoop user to the sudo group.

$ sudo usermod -aG sudo hadoop

Switch to the created user.

$ sudo su - hadoop

Install the OpenSSH server and client.

$ apt install openssh-server openssh-client -y

When you get a prompt, respond with:

keep the local version currently installed

Switch to the created user.

$ sudo su - hadoop

Generate public and private key pairs.

$ ssh-keygen -t rsa

Add the generated public key from id_rsa.pub to authorized_keys.

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

Change the permissions of the authorized_keys file.

$ sudo chmod 640 ~/.ssh/authorized_keys

Verify if the password-less SSH is functional.

$ ssh localhost

3. Install Apache Hadoop

Log in with hadoop user.

$ sudo su - hadoop

Download the latest stable version of Hadoop. To get the latest version, go to Apache Hadoop official download page.

$ wget https://downloads.apache.org/hadoop/common/hadoop-3.3.1/hadoop-3.3.1.tar.gz

Extract the downloaded file.

$ tar -xvzf hadoop-3.3.1.tar.gz

Move the extracted directory to the /usr/local/ directory.

$ sudo mv hadoop-3.3.1 /usr/local/hadoop

Create directory to store system logs.

$ sudo mkdir /usr/local/hadoop/logs

Change the ownership of the hadoop directory.

$ sudo chown -R hadoop:hadoop /usr/local/hadoop

4. Configure Hadoop

Edit file ~/.bashrc to configure the Hadoop environment variables.

$ sudo nano ~/.bashrc

Add the following lines to the file. Save and close the file.

export HADOOP_HOME=/usr/local/hadoop
export HADOOP_INSTALL=$HADOOP_HOME
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export YARN_HOME=$HADOOP_HOME
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export PATH=$PATH:$HADOOP_HOME/sbin:$HADOOP_HOME/bin
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib/native"

Activate the environment variables.

$ source ~/.bashrc

5. Configure Java Environment Variables

Hadoop has a lot of components that enable it to perform its core functions. To configure these components such as YARN, HDFS, MapReduce, and Hadoop-related project settings, you need to define Java environment variables in hadoop-env.sh configuration file.

Find the Java path.

$ which javac

Find the OpenJDK directory.

$ readlink -f /usr/bin/javac

Edit the hadoop-env.sh file.

$ sudo nano $HADOOP_HOME/etc/hadoop/hadoop-env.sh

Add the following lines to the file. Then, close and save the file.

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
export HADOOP_CLASSPATH+=" $HADOOP_HOME/lib/*.jar"

Browse to the hadoop lib directory.

$ cd /usr/local/hadoop/lib

Download the Javax activation file.

$ sudo wget https://jcenter.bintray.com/javax/activation/javax.activation-api/1.2.0/javax.activation-api-1.2.0.jar

Verify the Hadoop version.

$ hadoop version

Edit the core-site.xml configuration file to specify the URL for your NameNode.

$ sudo nano $HADOOP_HOME/etc/hadoop/core-site.xml

Add the following lines. Save and close the file.

<configuration>
   <property>
      <name>fs.default.name</name>
      <value>hdfs://0.0.0.0:9000</value>
      <description>The default file system URI</description>
   </property>
</configuration>

Create a directory for storing node metadata and change the ownership to hadoop.

$ sudo mkdir -p /home/hadoop/hdfs/{namenode,datanode}

$ sudo chown -R hadoop:hadoop /home/hadoop/hdfs

Edit hdfs-site.xml configuration file to define the location for storing node metadata, fs-image file.

$ sudo nano $HADOOP_HOME/etc/hadoop/hdfs-site.xml

Add the following lines. Close and save the file.

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

   <property>
      <name>dfs.name.dir</name>
      <value>file:///home/hadoop/hdfs/namenode</value>
   </property>

   <property>
      <name>dfs.data.dir</name>
      <value>file:///home/hadoop/hdfs/datanode</value>
   </property>
</configuration>

Edit mapred-site.xml configuration file to define MapReduce values.

$ sudo nano $HADOOP_HOME/etc/hadoop/mapred-site.xml

Add the following lines. Save and close the file.

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

Edit the yarn-site.xml configuration file and define YARN-related settings.

$ sudo nano $HADOOP_HOME/etc/hadoop/yarn-site.xml

Add the following lines. Save and close the file.

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

Log in with hadoop user.

$ sudo su - hadoop

Validate the Hadoop configuration and format the HDFS NameNode.

$ hdfs namenode -format

6. Start the Apache Hadoop Cluster

Start the NameNode and DataNode.

$ start-dfs.sh

Start the YARN resource and node managers.

$ start-yarn.sh

Verify all the running components.

$ jps

7. Access Apache Hadoop Web Interface

You can access the Hadoop NameNode on your browser via http://server-IP:9870. For example:

http://192.0.2.11:9870

Conclusion

You have successfully installed Apache Hadoop on your server. You can now access the dashboard and configure your preferences.

More Information

For more information on Apache Hadoop, please see the official documentation.