docker-management

Docker 管理

构建、运行和管理 Docker 容器，用于应用部署和开发。

何时使用此技能

在以下情况下使用此技能：

• 创建和优化 Dockerfile
• 构建并标记 Docker 镜像
• 运行和管理容器
• 调试容器问题
• 配置 Docker 网络和卷
• 落实容器安全最佳实践

前置条件

• 已安装 Docker Engine（20.10+）
• 具备基本的命令行知识
• 了解应用部署

Dockerfile 最佳实践

多阶段构建

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

# Production stage
FROM node:20-alpine AS production
WORKDIR /app
RUN addgroup -g 1001 -S nodejs && \
    adduser -S nodejs -u 1001
COPY --from=builder --chown=nodejs:nodejs /app/dist ./dist
COPY --from=builder --chown=nodejs:nodejs /app/node_modules ./node_modules
USER nodejs
EXPOSE 3000
CMD ["node", "dist/index.js"]

层优化

FROM python:3.12-slim

# Install dependencies first (cached unless requirements change)
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application code (changes frequently)
COPY . .

CMD ["python", "app.py"]

安全加固

FROM node:20-alpine

# Create non-root user
RUN addgroup -g 1001 appgroup && \
    adduser -u 1001 -G appgroup -D appuser

WORKDIR /app

# Copy with proper ownership
COPY --chown=appuser:appgroup . .

# Drop privileges
USER appuser

# Use exec form for proper signal handling
CMD ["node", "server.js"]

构建镜像

基本构建

# Build with tag
docker build -t myapp:1.0 .

# Build with build args
docker build --build-arg NODE_ENV=production -t myapp:prod .

# Build for specific platform
docker build --platform linux/amd64 -t myapp:amd64 .

# Build with no cache
docker build --no-cache -t myapp:fresh .

多平台构建

# Create builder
docker buildx create --name multiplatform --use

# Build for multiple architectures
docker buildx build \
  --platform linux/amd64,linux/arm64 \
  -t myregistry/myapp:latest \
  --push .

运行容器

基本操作

# Run container
docker run -d --name myapp -p 8080:3000 myapp:latest

# Run with environment variables
docker run -d \
  -e DATABASE_URL=postgres://localhost/db \
  -e NODE_ENV=production \
  myapp:latest

# Run with resource limits
docker run -d \
  --memory="512m" \
  --cpus="1.0" \
  myapp:latest

# Run with restart policy
docker run -d --restart=unless-stopped myapp:latest

卷管理

# Named volume
docker volume create mydata
docker run -v mydata:/app/data myapp:latest

# Bind mount
docker run -v $(pwd)/config:/app/config:ro myapp:latest

# tmpfs mount (memory)
docker run --tmpfs /tmp:rw,noexec,nosuid myapp:latest

网络

# Create network
docker network create mynetwork

# Run on network
docker run -d --network mynetwork --name api myapp:latest

# Connect existing container
docker network connect mynetwork existing-container

# Expose specific ports
docker run -d -p 127.0.0.1:8080:3000 myapp:latest

容器生命周期

管理命令

# List containers
docker ps -a

# Stop container
docker stop myapp

# Remove container
docker rm myapp

# Force remove running container
docker rm -f myapp

# Prune stopped containers
docker container prune -f

日志和监控

# View logs
docker logs myapp

# Follow logs
docker logs -f --tail 100 myapp

# View resource usage
docker stats myapp

# Inspect container
docker inspect myapp

调试容器

交互式访问

# Execute command in running container
docker exec -it myapp /bin/sh

# Run container with shell
docker run -it --rm myapp:latest /bin/sh

# Debug failed container
docker run -it --entrypoint /bin/sh myapp:latest

故障排除

# Check container logs for errors
docker logs myapp 2>&1 | grep -i error

# Inspect container state
docker inspect --format='{{.State.Status}}' myapp

# Check container processes
docker top myapp

# View container filesystem changes
docker diff myapp

# Export container filesystem
docker export myapp > myapp-fs.tar

健康检查

HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:3000/health || exit 1

# Check health status
docker inspect --format='{{.State.Health.Status}}' myapp

镜像管理

标记和推送

# Tag image
docker tag myapp:latest myregistry.com/myapp:v1.0

# Push to registry
docker push myregistry.com/myapp:v1.0

# Pull image
docker pull myregistry.com/myapp:v1.0

清理

# Remove unused images
docker image prune -a

# Remove all unused resources
docker system prune -a --volumes

# Remove specific image
docker rmi myapp:old

# List image sizes
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}"

镜像分析

# View image history
docker history myapp:latest

# Inspect image layers
docker inspect myapp:latest

# Check image vulnerabilities (with Docker Scout)
docker scout cves myapp:latest

Docker Compose 集成

# docker-compose.yml
version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
    volumes:
      - app-data:/app/data
    depends_on:
      - db
    restart: unless-stopped

  db:
    image: postgres:15-alpine
    environment:
      POSTGRES_PASSWORD: secret
    volumes:
      - db-data:/var/lib/postgresql/data

volumes:
  app-data:
  db-data:

安全最佳实践

镜像安全

# Use specific version tags
FROM node:20.10-alpine3.18

# Don't run as root
USER nobody

# Remove unnecessary packages
RUN apk del --purge build-dependencies

# Use COPY instead of ADD
COPY . .

运行时安全

# Run with security options
docker run -d \
  --security-opt=no-new-privileges \
  --cap-drop=ALL \
  --cap-add=NET_BIND_SERVICE \
  --read-only \
  myapp:latest

# Use user namespace remapping
# Add to /etc/docker/daemon.json: {"userns-remap": "default"}

常见问题

问题：容器立即退出

问题：容器启动后立即停止 解决方案：检查 CMD/ENTRYPOINT 是否运行前台进程，并使用 docker logs 查看错误

问题：无法连接到容器

问题：端口无法访问 解决方案：确认端口映射（-p）正确，检查容器是否正在运行，并确认防火墙规则

问题：磁盘空间不足

问题：Docker 占用过多磁盘空间 解决方案：运行 docker system prune -a --volumes，检查是否存在较大的未使用镜像

问题：构建缓存不起作用

问题：每次构建都会下载依赖项 解决方案：按照从最不常变更到最常变更的顺序排列 Dockerfile 指令

最佳实践

• 使用多阶段构建来减小镜像体积
• 切勿将机密信息存储在镜像中，应在运行时注入
• 固定基础镜像版本以确保可复现性
• 为生产环境中的容器实现健康检查
• 使用 .dockerignore 排除不必要的文件
• 以非 root 用户身份运行容器
• 定期扫描镜像中的漏洞
• 使用 Docker BuildKit 加快构建速度

相关技能

• docker-compose - 多容器应用
• container-scanning - 安全扫描
• container-hardening - 安全加固