DevOps

DevOps Skill

Overview

Skill สำหรับ containerization, orchestration, และ automation ของ software delivery

Docker

Dockerfile Best Practices

Multi-stage Build

# Stage 1: Build
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Stage 2: Production
FROM node:20-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production

# Non-root user for security
RUN addgroup -g 1001 -S nodejs && \
    adduser -S nextjs -u 1001

COPY --from=builder --chown=nextjs:nodejs /app/.next ./.next
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./package.json

USER nextjs
EXPOSE 3000
CMD ["npm", "start"]

Optimization Tips

# 1. Order layers by change frequency (least to most)
COPY package*.json ./
RUN npm ci
COPY . .

# 2. Use .dockerignore
# .dockerignore
node_modules
.git
*.md
.env*

# 3. Use specific base image versions
FROM node:20.10-alpine3.19

# 4. Combine RUN commands
RUN apt-get update && \
    apt-get install -y --no-install-recommends curl && \
    rm -rf /var/lib/apt/lists/*

Docker Compose

Development Environment

version: "3.8"

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile.dev
    ports:
      - "3000:3000"
    volumes:
      - .:/app
      - /app/node_modules
    environment:
      - NODE_ENV=development
      - DATABASE_URL=postgresql://user:pass@db:5432/mydb
    depends_on:
      db:
        condition: service_healthy

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    volumes:
      - postgres_data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d mydb"]
      interval: 5s
      timeout: 5s
      retries: 5

  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"

volumes:
  postgres_data:

Common Commands

# Build and start
docker compose up --build

# Start in background
docker compose up -d

# View logs
docker compose logs -f app

# Execute command in container
docker compose exec app sh

# Stop and remove
docker compose down

# Remove with volumes
docker compose down -v

Kubernetes

Core Concepts

Pod

apiVersion: v1
kind: Pod
metadata:
  name: myapp
  labels:
    app: myapp
spec:
  containers:
    - name: myapp
      image: myregistry/myapp:1.0.0
      ports:
        - containerPort: 3000
      resources:
        requests:
          memory: "128Mi"
          cpu: "100m"
        limits:
          memory: "256Mi"
          cpu: "200m"

Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
        - name: myapp
          image: myregistry/myapp:1.0.0
          ports:
            - containerPort: 3000
          env:
            - name: DATABASE_URL
              valueFrom:
                secretKeyRef:
                  name: db-secret
                  key: url
          livenessProbe:
            httpGet:
              path: /health
              port: 3000
            initialDelaySeconds: 30
            periodSeconds: 10
          readinessProbe:
            httpGet:
              path: /ready
              port: 3000
            initialDelaySeconds: 5
            periodSeconds: 5

Service

apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  type: ClusterIP
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 3000

ConfigMap & Secret

# ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
data:
  LOG_LEVEL: "info"
  FEATURE_FLAG: "true"

---
# Secret
apiVersion: v1
kind: Secret
metadata:
  name: db-secret
type: Opaque
stringData:
  url: postgresql://user:pass@db:5432/mydb

Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
spec:
  ingressClassName: nginx
  tls:
    - hosts:
        - myapp.example.com
      secretName: myapp-tls
  rules:
    - host: myapp.example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: myapp
                port:
                  number: 80

Common Commands

# Apply manifests
kubectl apply -f deployment.yaml

# Get resources
kubectl get pods
kubectl get deployments
kubectl get services

# Describe resource
kubectl describe pod myapp-xxx

# View logs
kubectl logs -f myapp-xxx

# Execute in pod
kubectl exec -it myapp-xxx -- sh

# Port forward
kubectl port-forward svc/myapp 8080:80

# Scale deployment
kubectl scale deployment myapp --replicas=5

# Rolling update
kubectl set image deployment/myapp myapp=myregistry/myapp:2.0.0

# Rollback
kubectl rollout undo deployment/myapp

CI/CD

GitHub Actions

name: CI/CD Pipeline

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

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

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: "20"
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Run linter
        run: npm run lint

      - name: Run tests
        run: npm test -- --coverage

      - name: Upload coverage
        uses: codecov/codecov-action@v3

  build:
    needs: test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'

    steps:
      - uses: actions/checkout@v4

      - name: Login to Container Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: |
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }}
            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest

  deploy:
    needs: build
    runs-on: ubuntu-latest
    environment: production

    steps:
      - name: Deploy to Kubernetes
        uses: azure/k8s-deploy@v4
        with:
          manifests: k8s/
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }}

Monitoring & Logging

Health Endpoints

// Express.js
app.get("/health", (req, res) => {
  res.json({ status: "healthy" });
});

app.get("/ready", async (req, res) => {
  try {
    await db.query("SELECT 1");
    res.json({ status: "ready" });
  } catch (error) {
    res.status(503).json({ status: "not ready", error: error.message });
  }
});

Logging Best Practices

// Structured logging
const logger = {
  info: (message, meta = {}) => {
    console.log(
      JSON.stringify({
        level: "info",
        message,
        timestamp: new Date().toISOString(),
        ...meta,
      }),
    );
  },
};

logger.info("User created", { userId: 123, action: "create" });

DevOps Checklist

• Dockerfile optimized (multi-stage, small image)
• docker-compose.yml for local development
• Kubernetes manifests (Deployment, Service, Ingress)
• ConfigMaps และ Secrets
• Health และ Readiness probes
• Resource limits configured
• CI/CD pipeline setup
• Monitoring และ logging
• Backup strategy
• Disaster recovery plan