Docker từ Cơ bản đến Nâng cao

Phần 3: Networking, Storage và Compose Nâng cao

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1. Compose Profiles

Profiles cho phép bạn chọn services nào sẽ được start, phù hợp cho multiple environments:

services:
  api:
    image: myapp:latest
    # Không có profile → luôn start

  db:
    image: postgres:16
    # Không có profile → luôn start

  adminer:
    image: adminer
    profiles:
      - debug
    ports:
      - "8080:8080"

  prometheus:
    image: prom/prometheus
    profiles:
      - monitoring

  grafana:
    image: grafana/grafana
    profiles:
      - monitoring

# Start default services (api, db)
docker compose up -d

# Start với debug profile
docker compose --profile debug up -d

# Start với monitoring profile
docker compose --profile monitoring up -d

# Start với nhiều profiles
docker compose --profile debug --profile monitoring up -d

2. Override Files

Docker Compose tự động merge docker-compose.yml với docker-compose.override.yml:

# docker-compose.yml (base)
services:
  api:
    build: .
    ports:
      - "3000:3000"
    environment:
      NODE_ENV: production

# docker-compose.override.yml (development - auto-loaded)
services:
  api:
    volumes:
      - ./src:/app/src
    environment:
      NODE_ENV: development
      DEBUG: "true"
    command: npm run dev

# docker-compose.prod.yml (production - manual)
services:
  api:
    image: registry.example.com/myapp:latest
    deploy:
      replicas: 3
      resources:
        limits:
          cpus: '1.0'
          memory: 512M
    restart: always

# Development (auto-loads override)
docker compose up -d

# Production (explicit files)
docker compose -f docker-compose.yml -f docker-compose.prod.yml up -d

3. Variable Substitution

# docker-compose.yml
services:
  api:
    image: ${REGISTRY:-docker.io}/${IMAGE_NAME:-myapp}:${TAG:-latest}
    ports:
      - "${API_PORT:-3000}:3000"
    environment:
      DB_HOST: ${DB_HOST:-db}
      DB_PASSWORD: ${DB_PASSWORD:?Database password is required}

# .env file (auto-loaded)
REGISTRY=harbor.example.com
IMAGE_NAME=myapp
TAG=v1.2.3
API_PORT=8080
DB_HOST=db
DB_PASSWORD=mysecretpassword

Syntax:

• ${VAR} - Sử dụng biến, lỗi nếu không set

• ${VAR:-default} - Default value nếu không set hoặc empty

• ${VAR-default} - Default value nếu không set

• ${VAR:?error} - Lỗi với message nếu không set

4. Deploy Configuration

services:
  api:
    image: myapp:latest
    deploy:
      replicas: 3
      resources:
        limits:
          cpus: '0.50'
          memory: 256M
        reservations:
          cpus: '0.25'
          memory: 128M
      restart_policy:
        condition: on-failure
        delay: 5s
        max_attempts: 3
        window: 120s
      update_config:
        parallelism: 1
        delay: 10s
        order: start-first
      rollback_config:
        parallelism: 1
        delay: 5s

5. Extends

# common.yml
services:
  base-app:
    build: .
    environment:
      LOG_LEVEL: info
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3

# docker-compose.yml
services:
  api:
    extends:
      file: common.yml
      service: base-app
    ports:
      - "3000:3000"
    environment:
      SERVICE_NAME: api

  worker:
    extends:
      file: common.yml
      service: base-app
    command: npm run worker
    environment:
      SERVICE_NAME: worker

6. Compose Watch (Hot Reload)

Compose Watch cho phép tự động sync files và rebuild khi code thay đổi:

services:
  api:
    build: .
    develop:
      watch:
        # Sync source code (hot reload)
        - action: sync
          path: ./src
          target: /app/src
    # Rebuild khi dependencies thay đổi
    - action: rebuild
      path: ./package.json

    # Sync + restart khi config thay đổi
    - action: sync+restart
      path: ./config
      target: /app/config

# Start với watch mode
docker compose watch

# Hoặc
docker compose up --watch

7. Scaling Services

# Scale service
docker compose up -d --scale api=3
Hoặc trong compose file
services:
api:
deploy:
replicas: 3

# Load balancing với Nginx
services:
  nginx:
    image: nginx:1.27-alpine
    ports:
      - "80:80"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
    depends_on:
      - api

  api:
    build: .
    deploy:
      replicas: 3
    # Không expose ports ra host, chỉ qua nginx

8. Production-ready Compose Configuration

# docker-compose.prod.yml
services:
  api:
    image: harbor.example.com/myapp:${TAG}
    deploy:
      replicas: 2
      resources:
        limits:
          cpus: '1.0'
          memory: 512M
    environment:
      NODE_ENV: production
    healthcheck:
      test: ["CMD", "wget", "--spider", "-q", "http://localhost:3000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 40s
    restart: unless-stopped
    logging:
      driver: json-file
      options:
        max-size: "10m"
        max-file: "3"
    read_only: true
    tmpfs:
      - /tmp
    security_opt:
      - no-new-privileges:true

9. Tổng kết

Trong bài này, bạn đã nắm được:

• Compose Profiles cho multiple environments

• Override files cho dev/staging/production

• Variable substitution với .env files

• Deploy configuration và resource limits

• Extends để tái sử dụng common configuration

• Compose Watch cho hot-reload development

• Scaling services và production-ready configurations

Bài tiếp theo sẽ hướng dẫn quản lý Environment Variables, Secrets và Configuration.