Docker et Kubernetes: Guide DevOps

La containerisation est devenue essentielle pour les applications modernes.

Docker: Les Fondamentaux

Dockerfile Optimisé

Code
FROM node:22-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production

FROM node:22-alpine
WORKDIR /app
COPY --from=builder /app/node_modules ./node_modules
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]

Multi-stage Builds

• Images plus légères
• Sécurité améliorée
• Build cache optimisé

Kubernetes: Orchestration

Deployment

Code
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    spec:
      containers:
      - name: web
        image: myapp:latest
        ports:
        - containerPort: 3000
        resources:
          limits:
            memory: "256Mi"
            cpu: "500m"

Auto-scaling

Code
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: web-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      targetAverageUtilization: 70

Bonnes Pratiques

1. Images minimales : Alpine ou Distroless
2. Health checks : Liveness et Readiness probes
3. Secrets management : Vault ou Sealed Secrets
4. GitOps : ArgoCD ou Flux

Conclusion

Docker + Kubernetes = Infrastructure scalable et résiliente.