Shell Script | Install Logstash on Linux machines

What is Logstash?

Logstash is an open-source, lightweight, free, server-side data processing pipeline. It stands for the "L" in the ELK Stack, with the help of which we can pull data from diverse sources using input plugins. We can then apply numerous transformations and enhancements using filter plugins, and finally, ship the data to various destinations using output plugins. Logstash provides the advantage of selecting, mixing and utilizing different inputs, filters and outputs according to our requirements to work in a consistent manner.

Today's Agenda

In this post, we will learn how to install Logstash on Linux machines. This script becomes really helpful in cases where we have multiple servers on which we need Logstash to be installed. Also, it will detect the Server OS version and run the installation accordingly.

Prerequisite

This post has been prepared for the audience who :

Have access to a Linux-based system like Ubuntu, CentOS, Redhat, etc.
Have Java installed on the system (Java 8 or Java 11).
Have a basic understanding of Linux-based systems and their commands.
And finally, are eager to learn and try something new.

Let's get started

Step 1: Create a new file to store the shell script.

Create a file with the name SetupLoggingAgent-Logstash.sh and add the below script to it.

#!/bin/bash

if [ "${1}" == "-h" ] || [ "${1}" == "-help" ] || [ "${1}" == "" ]
then
echo "HELP SECTION FOR THIS SCRIPT!"
echo "This script needs user with root permissions to get executed."

echo -e "Logstash Installation Script\n Purpose: \n This Script will perform the following functions:
-- Install Logstash with required input parsers & output.

Usage:
FOR HELP:
bash SetupLoggingAgent-Logstash.sh -help
bash SetupLoggingAgent-Logstash.sh -h
bash SetupLoggingAgent-Logstash.sh
To BEGIN INSTALLATION:
bash SetupLoggingAgent-Logstash.sh -start"
exit 0
fi

if [ "${1}" == "-start" ]
then

sudo -n true
if [ $? -ne 0 ]
then
echo "Permission Denied! Try executing this script with root user permissions or try with sudo."
echo "For more information about this file use -h or -help along with the above command."
exit 3
fi

set -e

###########################################################
## JAVA installation on the client machine
###########################################################

JAVA_version_check_debian() {
java -version
if [ $? -ne 0 ]
then
# Installing Java 8 if it's not installed
sudo apt-get install openjdk-8-jre-headless -y
# Checking if java installed is less than version 8. If yes, installing Java 8. As logstash & Elasticsearch require Java 8 or later.
elif [ "`java -version 2> /tmp/version && awk '/version/ { gsub(/"/, "", $NF); print ( $NF < 1.8 ) ? "YES" : "NO" }' /tmp/version`" == "YES" ]
then
sudo apt-get install openjdk-8-jre-headless -y
fi
}

JAVA_version_check_redhat() {
java -version
if [ $? -ne 0 ]
then
#Installing Java 8 if it's not installed
sudo yum install jre-1.8.0-openjdk -y
# Checking if java installed is less than version 8. If yes, installing Java 8. As logstash & Elasticsearch require Java 8 or later.
elif [ "`java -version 2> /tmp/version && awk '/version/ { gsub(/"/, "", $NF); print ( $NF < 1.8 ) ? "YES" : "NO" }' /tmp/version`" == "YES" ]
then
sudo yum install jre-1.8.0-openjdk -y
fi
}

###########################################################
## install logstash on the client machine
###########################################################

debian_logstash() {
# resynchronize the package index files from their sources.
sudo apt-get update
# Downloading Debian package of logstash
sudo wget https://artifacts.elastic.co/downloads/logstash/logstash-7.13.2-amd64.deb
# Install logstash Debian package
sudo dpkg -i logstash-7.13.2-amd64.deb
# Starting The Service
sudo systemctl start logstash
sudo systemctl enable logstash

sudo rm -f ./logstash-7.13.2-amd64.deb
echo -e "All Installations Completed. \nYou are ready to go!"

}

redhat_logstash() {
#Installing wget.
sudo yum install wget -y
# Downloading rpm package of logstash
sudo wget https://artifacts.elastic.co/downloads/logstash/logstash-7.13.2-x86_64.rpm
# Install logstash rpm package
sudo rpm -ivh logstash-7.13.2-x86_64.rpm
# Starting The Services
sudo service logstash start

sudo rm -f ./logstash-7.13.2-x86_64.rpm
echo -e "All Installations Completed. \nYou are ready to go!"

}

###########################################################
## CHECK OS VERSION OF THE CLIENT SYSTEM
###########################################################

if [ "$(grep -Ei 'debian|Ubuntu|mint' /etc/*release)" ]
then
echo " It's a Debian based system"
JAVA_version_check_debian
debian_logstash
elif [ "$(grep -Ei 'fedora|redhat|centos' /etc/*release)" ]
then
echo "It's a RedHat based system."
JAVA_version_check_redhat
redhat_logstash
else
echo "This script doesn't support this OS."
echo "Please follow this link to find other installation options: https://www.elastic.co/downloads/logstash"
exit 3
fi
fi

Step 2 : Run this Shell Script to begin Installation.

This Shell Script needs to be run as a root user.

To know how this shell script works, enter the below command:

bash SetupLoggingAgent-Logstash.sh -help

Add the asked variables and run the Shell Script as the root user.

sudo bash SetupLoggingAgent-Logstash.sh -start

That's all, you did a great job !!

If you face any issues or need any suggestions, please comment down below and hit the like button to appreciate the efforts.

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