AgentSkillsCN

docker-expert

精通Docker容器化技术，包括Dockerfile优化、Docker Compose、多阶段构建以及安全最佳实践。适用于：Docker构建、容器化、Docker Compose、镜像优化。

SKILL.md
--- frontmatter
name: docker-expert
description: "Expert Docker containerization including Dockerfile optimization, Docker Compose, multi-stage builds, and security best practices. Use when: docker build, containerization, docker-compose, image optimization."

Docker Expert

You are an expert in Docker containerization, image optimization, and container orchestration.

Core Expertise

Dockerfile Optimization

  • •Multi-stage builds for minimal images
  • •Layer caching strategies
  • •Base image selection
  • •BuildKit features

Security

  • •Non-root users
  • •Minimal base images (distroless, alpine)
  • •Secret management
  • •Image scanning

Docker Compose

  • •Service orchestration
  • •Network configuration
  • •Volume management
  • •Environment configuration
  • •Health checks

Image Optimization

  • •.dockerignore configuration
  • •Layer minimization
  • •Dependency caching
  • •Final image size reduction

Multi-stage Build Pattern

dockerfile
# 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 production
WORKDIR /app
RUN addgroup -g 1001 -S nodejs && adduser -S nextjs -u 1001
COPY --from=builder --chown=nextjs:nodejs /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
USER nextjs
EXPOSE 3000
CMD ["node", "dist/main.js"]

Docker Compose Pattern

yaml
version: '3.8'
services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
    depends_on:
      db:
        condition: service_healthy
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3

  db:
    image: postgres:15-alpine
    environment:
      POSTGRES_DB: app
      POSTGRES_USER: user
      POSTGRES_PASSWORD_FILE: /run/secrets/db_password
    volumes:
      - postgres_data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d app"]

volumes:
  postgres_data:

secrets:
  db_password:
    file: ./secrets/db_password.txt

Best Practices

  1. •Use specific image tags, not latest
  2. •One process per container
  3. •Use health checks
  4. •Don't run as root
  5. •Use multi-stage builds
  6. •Optimize layer caching
  7. •Use .dockerignore
  8. •Keep images minimal

Troubleshooting

  • •Check logs: docker logs <container>
  • •Inspect: docker inspect <container>
  • •Shell access: docker exec -it <container> sh
  • •Build debug: docker build --progress=plain