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Chapter 12.2 - CI/CD with Kubernetes

Learning Objectives​

By the end of this chapter, you will be able to:

  • Understand CI/CD pipelines for Kubernetes
  • Configure GitHub Actions for Kubernetes
  • Implement GitLab CI/CD
  • Use GitOps with ArgoCD
  • Automate deployments
  • Implement deployment strategies

Introduction​

CI/CD pipelines automate the build, test, and deployment of applications in Kubernetes.

GitHub Actions​

Basic Pipeline​

name: Deploy to Kubernetes

on:
  push:
    branches: [main]

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v3
    
    - name: Build Docker image
      run: |
        docker build -t my-app:${{ github.sha }} .
        docker tag my-app:${{ github.sha }} my-registry/my-app:${{ github.sha }}
    
    - name: Push to registry
      run: |
        echo ${{ secrets.DOCKER_PASSWORD }} | docker login -u ${{ secrets.DOCKER_USERNAME }} --password-stdin
        docker push my-registry/my-app:${{ github.sha }}
    
    - name: Deploy to Kubernetes
      uses: azure/k8s-deploy@v4
      with:
        manifests: |
          k8s/deployment.yaml
          k8s/service.yaml
        images: |
          my-registry/my-app:${{ github.sha }}
        kubectl-version: 'latest'

GitLab CI/CD​

.gitlab-ci.yml​

stages:
  - build
  - test
  - deploy

build:
  stage: build
  script:
    - docker build -t $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA

test:
  stage: test
  script:
    - docker run $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA npm test

deploy:
  stage: deploy
  script:
    - kubectl set image deployment/my-app app=$CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
  only:
    - main

GitOps with ArgoCD​

Installation​

# Install ArgoCD
kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

ArgoCD Application​

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/user/my-app
    targetRevision: main
    path: k8s
  destination:
    server: https://kubernetes.default.svc
    namespace: production
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
    - CreateNamespace=true

Deployment Strategies​

Rolling Update​

spec:
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0

Blue/Green​

Deploy a new version in parallel, then switch traffic.

Canary​

Gradually deploy to a percentage of users.

Best Practices​

1. Automated Tests​

Run tests before each deployment.

2. Environments​

Separate dev, staging, production.

3. Approvals​

Require approvals for production.

4. Rollback​

Have a fast rollback plan.

5. Monitoring​

Monitor deployments in real time.

Summary​

In this chapter, you learned:

CI/CD: Automation of build, test, and deployment
GitHub Actions: Integrated CI/CD pipelines
GitLab CI: Pipelines with .gitlab-ci.yml
GitOps: ArgoCD for declarative deployments
Strategies: Rolling, Blue/Green, Canary
Best practices: Tests, environments, approvals, rollback

Next Steps​

Chapter 12.3: Environments
Lab 12.2: Horizontal and Vertical Autoscaling
Lab 12.3: GitOps with ArgoCD

Chapter created on: December 2024