docker-devops

Docker & DevOps Skill

Dockerfile Best Practices

Multi-Stage Build (Node.js)

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

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

# Non-root user
RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
COPY --from=builder --chown=nextjs:nodejs /app/public ./public

USER nextjs
EXPOSE 3000
CMD ["node", "server.js"]

Multi-Stage Build (Python)

# Build stage
FROM python:3.12-slim AS builder
WORKDIR /app
RUN pip install --no-cache-dir poetry
COPY pyproject.toml poetry.lock ./
RUN poetry export -f requirements.txt -o requirements.txt

# Production stage
FROM python:3.12-slim
WORKDIR /app

# Non-root user
RUN useradd -m -u 1000 appuser

COPY --from=builder /app/requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

COPY --chown=appuser:appuser . .
USER appuser

EXPOSE 8000
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]

---

Docker Compose Patterns

Development Setup

version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile.dev
    volumes:
      - .:/app
      - /app/node_modules
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=development
      - DATABASE_URL=postgresql://postgres:postgres@db:5432/app
    depends_on:
      - db
      - redis

  db:
    image: postgres:16-alpine
    volumes:
      - postgres_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: app
    ports:
      - "5432:5432"

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

volumes:
  postgres_data:

Production Setup

version: '3.8'

services:
  app:
    image: ${REGISTRY}/app:${TAG}
    restart: unless-stopped
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - DATABASE_URL=${DATABASE_URL}
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
    deploy:
      resources:
        limits:
          cpus: '1'
          memory: 512M