CI/CD Pipeline Explained with Real-Life Example (Jenkins + GitHub + Docker + K8s)

CI/CD Pipeline Explained with Real-Life Example (Jenkins + GitHub + Docker + K8s)

In DevOps, CI/CD pipelines are the heartbeat of modern software delivery. They automate everything from code commit to deployment. In this blog, I’ll explain what CI/CD means and walk you through a real-world pipeline using tools like GitHub, Jenkins, Docker, and Kubernetes.

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🚀 What is CI/CD?

• CI (Continuous Integration) – Automatically builds and tests every code change pushed to version control.
• CD (Continuous Delivery or Deployment) – Automatically delivers or deploys code to production once it passes all stages.

Together, CI/CD eliminates manual effort and accelerates software delivery.

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🔍 Why CI/CD Matters in DevOps

• Reduces human errors
• Enables fast feedback for developers
• Supports agile teams with continuous updates
• Improves code quality through automated testing

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🔄 CI vs CD: The Difference

Continuous Integration (CI)	Continuous Delivery/Deployment (CD)
Code integration + testing	Deployment to staging or prod
Focuses on code quality	Focuses on release automation
Tools: Jenkins, GitHub Actions	Tools: Spinnaker, ArgoCD, Helm

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🧪 Real-Life CI/CD Pipeline Example

Here’s a simplified but real example of how I set up CI/CD using Jenkins + GitHub + Docker + Kubernetes in a client project:

🔧 Tools Used:

• GitHub – Code repo
• Jenkins – CI/CD automation server
• Docker – Containerization
• Docker Hub – Image registry
• Kubernetes (EKS) – Container orchestration

🧬 Pipeline Steps:

1. Code Push: Developer pushes code to main branch on GitHub.
2. Jenkins Trigger: Jenkins pipeline is triggered using GitHub webhook.
3. Build & Test:
   • Code is pulled from GitHub
   • Unit tests run
   • App is built using Maven or npm
4. Dockerize:
   • Docker image is built
   • Image is tagged with the commit ID
   • Pushed to Docker Hub
5. Deploy to Kubernetes:
   • Jenkins uses kubectl to apply updated YAML files
   • New version of the app is deployed to Kubernetes cluster (EKS)

💡 Example Jenkinsfile:

pipeline {
    agent any

    stages {
        stage('Clone') {
            steps {
                git 'https://github.com/your-org/your-app.git'
            }
        }
        stage('Build') {
            steps {
                sh 'npm install' // or mvn clean install
            }
        }
        stage('Docker Build & Push') {
            steps {
                sh '''
                docker build -t yourname/app:$BUILD_NUMBER .
                docker push yourname/app:$BUILD_NUMBER
                '''
            }
        }
        stage('Deploy to K8s') {
            steps {
                sh 'kubectl apply -f k8s/deployment.yaml'
            }
        }
    }
}

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📦 Popular CI/CD Tools You Can Explore

• Jenkins – Flexible and powerful
• GitHub Actions – Easy setup within GitHub
• GitLab CI – Great for GitLab users
• ArgoCD – GitOps-style continuous deployment to Kubernetes
• CircleCI – Cloud-native and developer-friendly

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🧭 Conclusion

Implementing CI/CD might look complex at first, but once it’s in place, it changes how teams deliver software. Start simple with GitHub + Jenkins, and scale by adding Docker and Kubernetes. Automate gradually and iterate as your projects grow.