Ci Cd Pipelines | Devops | Linux Tutorial

Introduction to CI/CD

CI/CD stands for Continuous Integration and Continuous Deployment. It is a method to frequently deliver apps to customers by introducing automation into the stages of app development. The main concepts attributed to CI/CD are continuous integration, continuous delivery, and continuous deployment. CI/CD bridges the gaps between development and operation activities and teams by enforcing automation in building, testing, and deployment of applications.

Continuous Integration

Continuous Integration (CI) is a development practice where developers integrate code into a shared repository frequently, preferably several times a day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible. Some key benefits include:

Early detection of integration bugs
Reduced integration problems
Automated tests to ensure quality

Example: A developer commits code to a shared repository. A CI server like Jenkins automatically tests and builds the code, ensuring that it integrates well with the existing codebase.

Continuous Delivery

Continuous Delivery (CD) is a software development practice where code changes are automatically prepared for a release to production. CD expands upon continuous integration by deploying all code changes to a testing environment and/or a production environment after the build stage. When properly implemented, developers will always have a deployment-ready build artifact that has passed through a standardized test process.

Example: After code is integrated and tested, it is automatically deployed to a staging environment where further tests can be conducted to ensure it's ready for production.

Continuous Deployment

Continuous Deployment goes a step further than Continuous Delivery. With this practice, every change that passes automated tests is automatically deployed to production. There is no human intervention, and only a failed test will prevent a new change to be deployed to production.

Example: Once the code passes all tests in the staging environment, it is automatically deployed to production, ensuring the latest version is always live.

Setting Up a CI/CD Pipeline

Setting up a CI/CD pipeline involves several steps. Below is a basic example using Jenkins, a popular open-source automation server.

Step 1: Install Jenkins

First, you need to install Jenkins on your server. On a Linux system, you can use the following commands:

sudo apt update

sudo apt install openjdk-8-jdk

wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -

sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'

sudo apt update

sudo apt install jenkins

sudo systemctl start jenkins

Step 2: Configure Jenkins

Once Jenkins is installed, navigate to http://localhost:8080. Follow the on-screen instructions to unlock Jenkins, install plugins, and create an admin user.

Step 3: Create a Pipeline

In Jenkins, you can create a new pipeline by navigating to New Item and selecting Pipeline. You can then define your pipeline script. Below is an example of a simple pipeline script:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'echo Building...'
                sh 'make'
            }
        }
        stage('Test') {
            steps {
                sh 'echo Testing...'
                sh 'make test'
            }
        }
        stage('Deploy') {
            steps {
                sh 'echo Deploying...'
                sh 'make deploy'
            }
        }
    }
}

This script defines three stages: Build, Test, and Deploy. Each stage runs a series of shell commands to build, test, and deploy the application.

Conclusion

CI/CD pipelines are essential for modern software development, enabling teams to deliver high-quality software rapidly and reliably. By integrating and automating the steps involved in software development, testing, and deployment, teams can ensure that their applications are always in a deployable state and can be released to users quickly and efficiently.

This tutorial provided a basic overview and a simple example to get you started with CI/CD pipelines using Jenkins. As you gain more experience, you can explore advanced features and integrate additional tools to further enhance your CI/CD processes.

CI/CD Pipelines Tutorial