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CI/CD Pipeline with Jenkins, Docker, and Kubernetes

This repository demonstrates a Jenkins pipeline that automates:

1. Checkout source code from GitHub
2. Build & Push a Docker image to a container registry
3. Deploy the application to a Kubernetes cluster

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🔧 Pipeline Overview

The pipeline uses the following key variables:

def dockerfile = 'dockerfile'
def registry = 'localhost:5000'
def imageName = 'myimage'
def imageTag = 'latest'
def manifestFile = 'kubernetes-manifest.yaml'
def namespace = 'default'
def IMAGE_BRANCH_TAG = "${registry}/${imageName}:${imageTag}"

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📜 Pipeline Stages

1. Checkout the Repository

git branch: 'master', url: 'https://github.com/amitopenwriteup/cicd.git'

• Clones the source code from the GitHub repository.

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2. Build and Push Docker Image

def dockerImage = docker.build("${registry}/${imageName}:${imageTag}", "-f ${dockerfile} .")
dockerImage.push()

• Builds a Docker image from the dockerfile.
• Tags it as localhost:5000/myimage:latest.
• Pushes the image to the registry.

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3. Apply Kubernetes Manifest

withCredentials([file(credentialsId: '9445dd9b-e604-40cd-a802-79f747011ecb', variable: 'KUBECONFIG')]) {
    sh """
    sed \
        -e "s|{{NAMESPACE}}|${namespace}|g" \
        -e "s|{{PULL_IMAGE}}|${IMAGE_BRANCH_TAG}|g" \
        ${manifestFile} \
    | kubectl apply -f -
    """
}

• Uses a stored Kubeconfig credential in Jenkins to connect to the cluster.

• Replaces placeholders in the Kubernetes manifest:

  • {{NAMESPACE}} → default
  • {{PULL_IMAGE}} → built Docker image

• Deploys the updated manifest with kubectl apply.

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📂 Repository Structure

├── Dockerfile                # Docker build instructions
├── kubernetes-manifest.yaml  # K8s deployment template with placeholders
├── Jenkinsfile               # Jenkins pipeline
└── requirements.txt          # Python dependencies (if applicable)

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🚀 Usage

1. Run Jenkins job

   • The pipeline will automatically build, push, and deploy.

2. Verify deployment

   kubectl get pods -n default
   kubectl get svc -n default

3. Access the application using the exposed service (LoadBalancer/NodePort/Ingress depending on manifest).

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✅ Prerequisites

• Jenkins with Docker & Kubernetes plugins installed
• Docker registry (local or remote)
• Kubernetes cluster accessible from Jenkins
• Properly configured KUBECONFIG in Jenkins credentials

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