Docker Compose实战

引言

Docker Compose是容器编排的利器。本文介绍Docker Compose的实战应用。

一、基础语法

1.1 docker-compose.yml结构

version: '3.8'

services:
  web:
    image: nginx:alpine
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html
    networks:
      - frontend
    depends_on:
      - api

  api:
    build: ./api
    environment:
      - DB_HOST=db
      - DB_PORT=3306
    networks:
      - frontend
      - backend

  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: root123
      MYSQL_DATABASE: mydb
    volumes:
      - db-data:/var/lib/mysql
    networks:
      - backend

networks:
  frontend:
  backend:

volumes:
  db-data:

二、常用命令

# 启动服务
docker-compose up -d

# 停止服务
docker-compose down

# 查看服务
docker-compose ps

# 查看日志
docker-compose logs -f web

# 重启服务
docker-compose restart web

# 构建镜像
docker-compose build

# 执行命令
docker-compose exec web sh

三、实战示例

3.1 Spring Boot + MySQL + Redis

version: '3.8'

services:
  app:
    build: .
    ports:
      - "8080:8080"
    environment:
      SPRING_DATASOURCE_URL: jdbc:mysql://db:3306/mydb
      SPRING_REDIS_HOST: redis
    depends_on:
      - db
      - redis
    networks:
      - app-network

  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: root123
      MYSQL_DATABASE: mydb
    volumes:
      - mysql-data:/var/lib/mysql
    networks:
      - app-network

  redis:
    image: redis:7-alpine
    volumes:
      - redis-data:/data
    networks:
      - app-network

networks:
  app-network:

volumes:
  mysql-data:
  redis-data:

3.2 前后端分离项目

version: '3.8'

services:
  frontend:
    build: ./frontend
    ports:
      - "80:80"
    depends_on:
      - backend
    networks:
      - app-network

  backend:
    build: ./backend
    ports:
      - "8080:8080"
    environment:
      DB_HOST: postgres
      REDIS_HOST: redis
    depends_on:
      - postgres
      - redis
    networks:
      - app-network

  postgres:
    image: postgres:15-alpine
    environment:
      POSTGRES_DB: mydb
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - postgres-data:/var/lib/postgresql/data
    networks:
      - app-network

  redis:
    image: redis:7-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis-data:/data
    networks:
      - app-network

networks:
  app-network:

volumes:
  postgres-data:
  redis-data:

3.3 ELK日志系统

version: '3.8'

services:
  elasticsearch:
    image: elasticsearch:8.9.0
    environment:
      - discovery.type=single-node
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
    volumes:
      - es-data:/usr/share/elasticsearch/data
    ports:
      - "9200:9200"
    networks:
      - elk

  logstash:
    image: logstash:8.9.0
    volumes:
      - ./logstash.conf:/usr/share/logstash/pipeline/logstash.conf
    ports:
      - "5044:5044"
    depends_on:
      - elasticsearch
    networks:
      - elk

  kibana:
    image: kibana:8.9.0
    ports:
      - "5601:5601"
    environment:
      ELASTICSEARCH_HOSTS: http://elasticsearch:9200
    depends_on:
      - elasticsearch
    networks:
      - elk

networks:
  elk:

volumes:
  es-data:

四、高级特性

4.1 环境变量

# .env文件
DB_PASSWORD=secret123
REDIS_PORT=6379

# docker-compose.yml
services:
  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: ${DB_PASSWORD}
  
  redis:
    image: redis:alpine
    ports:
      - "${REDIS_PORT}:6379"

4.2 健康检查

services:
  app:
    image: myapp:latest
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
      interval: 30s
      timeout: 3s
      retries: 3
      start_period: 40s

4.3 资源限制

services:
  app:
    image: myapp:latest
    deploy:
      resources:
        limits:
          cpus: '0.5'
          memory: 512M
        reservations:
          cpus: '0.25'
          memory: 256M

五、最佳实践

1. 使用.env文件管理环境变量
2. 使用volumes持久化数据
3. 使用networks隔离服务
4. 使用depends_on控制启动顺序
5. 使用健康检查确保服务可用
6. 使用restart: always自动重启

总结

Docker Compose核心：

1. 服务编排：简化多容器管理
2. 网络隔离：服务间通信
3. 数据持久化：volumes管理
4. 环境管理：.env文件配置

参考资料

• Docker Compose官方文档