CI/CD Pipelines

What is CI/CD?

CI/CD stands for Continuous Integration and Continuous Delivery/Deployment. It is a set of practices that enable development teams to deliver code changes more frequently and reliably. CI/CD is one of the cornerstone practices of DevOps.

Continuous Integration (CI)

Continuous Integration is the practice of merging all developers' working copies to a shared mainline several times a day. Each integration triggers an automated build and test process to detect integration errors as quickly as possible.

• Developers commit code frequently (at least daily)
• Each commit triggers an automated build
• Automated tests run on every build
• Bugs are detected and fixed quickly

Continuous Delivery vs Continuous Deployment

Continuous Delivery (CD)

Continuous Delivery ensures that code is always in a deployable state. Every change that passes all stages of the production pipeline is ready to be released to customers. However, the final deployment to production is a manual decision.

Continuous Deployment

Continuous Deployment goes one step further - every change that passes all stages of the production pipeline is automatically released to customers. There is no human intervention.

CI/CD Pipeline Stages

1. 📥 Source - Code commit triggers the pipeline
2. 🔨 Build - Compile code, create artifacts
3. 🧪 Test - Run unit, integration, and e2e tests
4. 📊 Analysis - Code quality, security scans
5. 📦 Package - Create deployable artifacts (Docker images)
6. 🚀 Deploy - Deploy to staging/production
7. 👁️ Monitor - Track application health

Popular CI/CD Tools

• Jenkins - Open-source automation server
• GitHub Actions - Native CI/CD for GitHub
• GitLab CI/CD - Built into GitLab
• CircleCI - Cloud-native CI/CD
• Travis CI - Hosted CI service
• Azure DevOps - Microsoft's CI/CD platform
• AWS CodePipeline - AWS native CI/CD

CI/CD Best Practices

• Keep pipelines fast (under 10 minutes if possible)
• Run tests in parallel
• Fail fast - stop pipeline on first failure
• Use feature flags for gradual rollouts
• Implement proper monitoring and alerting
• Practice infrastructure as code for environments

name: CI/CD Pipeline

on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.11'
      - name: Install dependencies
        run: pip install -r requirements.txt
      - name: Run tests
        run: pytest tests/ -v --cov=src
      
  build:
    needs: test
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build Docker image
        run: docker build -t myapp:${{ github.sha }} .
      - name: Push to registry
        run: |
          docker tag myapp:${{ github.sha }} registry/myapp:latest
          docker push registry/myapp:latest

  deploy:
    needs: build
    if: github.ref == 'refs/heads/main'
    runs-on: ubuntu-latest
    steps:
      - name: Deploy to production
        run: kubectl apply -f k8s/