Multi-Environment Pipeline: Dev → Staging → Production

# k8s/base/deployment.yaml (Common base)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:latest  # Overridden per environment
        ports:
        - containerPort: 8080
        envFrom:
        - configMapRef:
            name: myapp-config
        - secretRef:
            name: myapp-secrets
        resources:
          # Overridden per environment
          requests:
            memory: "128Mi"
            cpu: "100m"
          limits:
            memory: "256Mi"
            cpu: "200m"

---
# k8s/dev/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
  namespace: dev
data:
  NODE_ENV: "development"
  LOG_LEVEL: "debug"
  DATABASE_HOST: "postgres.dev.svc.cluster.local"
  REDIS_HOST: "redis.dev.svc.cluster.local"
  FEATURE_NEW_UI: "true"
  FEATURE_BETA_API: "true"

---
# k8s/staging/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
  namespace: staging
data:
  NODE_ENV: "staging"
  LOG_LEVEL: "info"
  DATABASE_HOST: "postgres.staging.svc.cluster.local"
  REDIS_HOST: "redis.staging.svc.cluster.local"
  FEATURE_NEW_UI: "true"
  FEATURE_BETA_API: "false"

---
# k8s/production/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
  namespace: production
data:
  NODE_ENV: "production"
  LOG_LEVEL: "warn"
  DATABASE_HOST: "postgres.production.svc.cluster.local"
  REDIS_HOST: "redis.production.svc.cluster.local"
  FEATURE_NEW_UI: "false"  # Gradual rollout
  FEATURE_BETA_API: "false"

---
# k8s/dev/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

namespace: dev

resources:
  - ../base/deployment.yaml
  - configmap.yaml
  - secrets.yaml

images:
  - name: myapp
    newTag: dev-abc123

replicas:
  - name: myapp
    count: 1

patches:
  - patch: |-
      - op: replace
        path: /spec/template/spec/containers/0/resources/requests/memory
        value: 128Mi
      - op: replace
        path: /spec/template/spec/containers/0/resources/limits/memory
        value: 256Mi      
    target:
      kind: Deployment
      name: myapp

---
# k8s/production/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

namespace: production

resources:
  - ../base/deployment.yaml
  - configmap.yaml
  - secrets.yaml

images:
  - name: myapp
    newTag: v1.2.3

replicas:
  - name: myapp
    count: 10

patches:
  - patch: |-
      - op: replace
        path: /spec/template/spec/containers/0/resources/requests/memory
        value: 512Mi
      - op: replace
        path: /spec/template/spec/containers/0/resources/limits/memory
        value: 1Gi
      - op: replace
        path: /spec/template/spec/containers/0/resources/requests/cpu
        value: 500m
      - op: replace
        path: /spec/template/spec/containers/0/resources/limits/cpu
        value: 1000m      
    target:
      kind: Deployment
      name: myapp

# .github/workflows/multi-env-deploy.yml
name: Multi-Environment Deployment

on:
  push:
    branches:
      - main
      - develop
  pull_request:
    branches:
      - main

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  # CI - Same for all environments
  build-and-test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Run linting
        run: npm run lint

      - name: Run unit tests
        run: npm test

      - name: Build Docker image
        run: docker build -t $IMAGE_NAME:${{ github.sha }} .

      - name: Run integration tests
        run: docker-compose -f docker-compose.test.yml up --abort-on-container-exit

      - name: Push image
        run: |
          echo ${{ secrets.GITHUB_TOKEN }} | docker login ghcr.io -u ${{ github.actor }} --password-stdin
          docker push $IMAGE_NAME:${{ github.sha }}          

  # Deploy to Dev - Auto on feature branches
  deploy-dev:
    needs: build-and-test
    if: github.ref != 'refs/heads/main'
    runs-on: ubuntu-latest
    environment:
      name: development
      url: https://dev.example.com
    steps:
      - uses: actions/checkout@v3

      - name: Deploy to Dev
        run: |
          kubectl config set-cluster dev --server="${{ secrets.DEV_K8S_SERVER }}"
          kubectl config set-credentials admin --token="${{ secrets.DEV_K8S_TOKEN }}"
          kubectl set image deployment/myapp myapp=$IMAGE_NAME:${{ github.sha }} -n dev
          kubectl rollout status deployment/myapp -n dev          

      - name: Run smoke tests
        run: |
          curl https://dev.example.com/health
          npm run test:smoke -- --env=dev          

  # Deploy to Staging - Auto on main branch
  deploy-staging:
    needs: build-and-test
    if: github.ref == 'refs/heads/main'
    runs-on: ubuntu-latest
    environment:
      name: staging
      url: https://staging.example.com
    steps:
      - uses: actions/checkout@v3

      - name: Run database migrations
        run: |
          kubectl exec -n staging deployment/postgres -- \
            psql -U postgres -d app -f /migrations/migrate.sql          

      - name: Deploy to Staging
        run: |
          kubectl config set-cluster staging --server="${{ secrets.STAGING_K8S_SERVER }}"
          kubectl config set-credentials admin --token="${{ secrets.STAGING_K8S_TOKEN }}"
          kubectl apply -k k8s/staging/
          kubectl rollout status deployment/myapp -n staging --timeout=5m          

      - name: Run E2E tests
        run: npm run test:e2e -- --env=staging

      - name: Run performance tests
        run: |
          k6 run --vus 10 --duration 30s tests/performance.js          

      - name: Check staging health
        run: |
          curl https://staging.example.com/health | jq '.status' | grep -q "healthy"          

  # Deploy to Production - Manual approval required
  deploy-production:
    needs: deploy-staging
    runs-on: ubuntu-latest
    environment:
      name: production
      url: https://example.com
    steps:
      - uses: actions/checkout@v3

      - name: Backup production database
        run: |
          kubectl exec -n production deployment/postgres -- \
            pg_dump -U postgres app > backup-$(date +%Y%m%d-%H%M%S).sql          

      - name: Run database migrations
        run: |
          kubectl exec -n production deployment/postgres -- \
            psql -U postgres -d app -f /migrations/migrate.sql          

      - name: Deploy to Production (Blue-Green)
        run: |
          kubectl config set-cluster prod --server="${{ secrets.PROD_K8S_SERVER }}"
          kubectl config set-credentials admin --token="${{ secrets.PROD_K8S_TOKEN }}"

          # Deploy green version
          kubectl apply -k k8s/production/
          kubectl rollout status deployment/myapp-green -n production --timeout=10m

          # Switch traffic to green
          kubectl patch service myapp -n production -p '{"spec":{"selector":{"version":"green"}}}'          

      - name: Monitor production metrics
        run: |
          sleep 300  # Wait 5 minutes
          ERROR_RATE=$(curl -s prometheus.example.com/api/v1/query?query=rate5m)
          if [ "$ERROR_RATE" -gt "0.01" ]; then
            echo "Error rate too high, rolling back"
            kubectl patch service myapp -n production -p '{"spec":{"selector":{"version":"blue"}}}'
            exit 1
          fi          

      - name: Notify team
        if: success()
        uses: slackapi/slack-github-action@v1
        with:
          payload: |
            {
              "text": "✅ Production deployment successful!",
              "version": "${{ github.sha }}",
              "deployed_by": "${{ github.actor }}"
            }