Imagine running a bakery chain. You don’t want each branch to bake bread differently — you need a system that ensures every loaf is consistent, tested, and delivered on time. In software, CI/CD pipelines are that system. For the Capstone Project, CI/CD ensures Docker images are built, tested, and deployed automatically, reducing human error and speeding up delivery.

CI-CD Foundations

1. What is CI/CD?

• Continuous Integration (CI): Automates building and testing code whenever changes are made.
• Continuous Delivery/Deployment (CD): Automates pushing validated builds into production environments.

2. Why CI/CD for Docker?

• Ensures consistent builds across environments.
• Automates testing inside containers.
• Pushes images to registries for deployment.
• Deploys services to Swarm or cloud clusters seamlessly.

3. CI/CD Workflow for Capstone Project

1. Code Commit: Developer pushes changes to Git.
2. CI Stage:
   • Build Docker images.
   • Run unit and integration tests.
   • Scan images for vulnerabilities.
3. CD Stage:
   • Push images to registry.
   • Deploy updated services to Swarm or cloud.
   • Rollback if deployment fails.

Things to Remember

• CI/CD pipelines are the automation backbone of modern DevOps.
• Docker integrates naturally with CI/CD tools (GitHub Actions, GitLab CI, Jenkins).
• Testing inside containers ensures reliability before deployment.
• Registries act as the bridge between CI and CD.

Hands‑On Lab

Step 1: GitHub Actions CI Pipeline

name: CI Pipeline

on:
  push:
    branches: [ "main" ]

jobs:
  build-test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Code
        uses: actions/checkout@v2

      - name: Build Docker Images
        run: docker-compose build

      - name: Run Tests
        run: docker-compose run backend npm test

Step 2: CD Pipeline (Deploy to Swarm)

jobs:
  deploy:
    runs-on: ubuntu-latest
    needs: build-test
    steps:
      - name: Login to Docker Hub
        run: echo "${{ secrets.DOCKER_PASSWORD }}" | docker login -u ${{ secrets.DOCKER_USERNAME }} --password-stdin

      - name: Push Images
        run: docker-compose push

      - name: Deploy to Swarm
        run: |
          docker stack deploy -c docker-compose.yml capstone

Step 3: Rollback Strategy

docker service update --rollback capstone_backend

Practice Exercise

1. Configure a CI pipeline to build and test Docker images for your services.
2. Add a CD pipeline to push images to Docker Hub or a private registry.
3. Deploy services to a Swarm cluster automatically.
4. Simulate a failed deployment and perform a rollback.
5. Reflect on how CI/CD improves speed, reliability, and collaboration.

Visual Learning Model

CI/CD Integration
   ├── CI → build, test, scan
   ├── Registry → push validated images
   ├── CD → deploy to Swarm/cloud
   └── Rollback → recover from failures

The Hackers Notebook

CI/CD integration automates the Capstone Project’s lifecycle. CI builds and tests Docker images, CD pushes them to registries and deploys them to production. Rollback strategies ensure resilience. Together, CI/CD pipelines transform containerized services into production‑ready applications.