/deployment-patterns

name: deployment-patterns
description: Deployment workflows, CI/CD pipeline patterns, Docker containerization, health checks, rollback strategies, and production readiness checklists for web applications.
origin: ECC

部署模式 (Deployment Patterns)

生产部署工作流与 CI/CD 最佳实践。

何时激活

• 设置 CI/CD 流水线 (Pipelines)
• 对应用程序进行 Docker 容器化
• 规划部署策略（蓝绿部署、金丝雀部署、滚动更新）
• 实现健康检查 (Health Checks) 与就绪探针 (Readiness Probes)
• 准备生产发布
• 配置环境特定的设置

部署策略 (Deployment Strategies)

滚动部署 (Rolling Deployment) - 默认

逐渐替换实例 —— 在滚动更新期间，旧版本和新版本同时运行。

实例 1: v1 → v2  (首先更新)
实例 2: v1        (仍在运行 v1)
实例 3: v1        (仍在运行 v1)

实例 1: v2
实例 2: v1 → v2  (其次更新)
实例 3: v1

实例 1: v2
实例 2: v2
实例 3: v1 → v2  (最后更新)

**优点：** 零停机时间，渐进式推出 **缺点：** 两个版本同时运行 —— 要求变更必须向后兼容 **适用场景：** 标准部署，向后兼容的变更

蓝绿部署 (Blue-Green Deployment)

运行两个完全相同的环境。原子化地切换流量。

蓝色环境 (v1) ← 流量接入
绿色环境 (v2)   空闲，运行新版本

# 验证后：
蓝色环境 (v1)   空闲 (变为备用)
绿色环境 (v2) ← 流量接入

**优点：** 瞬时回滚（切换回蓝色环境），干净的切割 **缺点：** 部署期间需要 2 倍的基础设施资源 **适用场景：** 关键服务，对问题零容忍

金丝雀部署 (Canary Deployment)

首先将小部分比例的流量路由到新版本。

v1: 95% 流量
v2:  5% 流量  (金丝雀)

# 如果指标良好：
v1: 50% 流量
v2: 50% 流量

# 最终：
v2: 100% 流量

**优点：** 在全量推出前通过真实流量发现问题 **缺点：** 需要流量切分基础设施和监控 **适用场景：** 高流量服务，高风险变更，特性标志 (Feature Flags)

Docker

多阶段 Dockerfile (Node.js)

# 阶段 1: 安装依赖
FROM node:22-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci --production=false

# 阶段 2: 构建
FROM node:22-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN npm run build
RUN npm prune --production

# 阶段 3: 生产镜像
FROM node:22-alpine AS runner
WORKDIR /app

RUN addgroup -g 1001 -S appgroup && adduser -S appuser -u 1001
USER appuser

COPY --from=builder --chown=appuser:appgroup /app/node_modules ./node_modules
COPY --from=builder --chown=appuser:appgroup /app/dist ./dist
COPY --from=builder --chown=appuser:appgroup /app/package.json ./

ENV NODE_ENV=production
EXPOSE 3000

HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD wget --no-verbose --tries=1 --spider http://localhost:3000/health || exit 1

CMD ["node", "dist/server.js"]

多阶段 Dockerfile (Go)

FROM golang:1.22-alpine AS builder
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server ./cmd/server

FROM alpine:3.19 AS runner
RUN apk --no-cache add ca-certificates
RUN adduser -D -u 1001 appuser
USER appuser

COPY --from=builder /server /server

EXPOSE 8080
HEALTHCHECK --interval=30s --timeout=3s CMD wget -qO- http://localhost:8080/health || exit 1
CMD ["/server"]

多阶段 Dockerfile (Python/Django)

FROM python:3.12-slim AS builder
WORKDIR /app
RUN pip install --no-cache-dir uv
COPY requirements.txt .
RUN uv pip install --system --no-cache -r requirements.txt

FROM python:3.12-slim AS runner
WORKDIR /app

RUN useradd -r -u 1001 appuser
USER appuser

COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
COPY --from=builder /usr/local/bin /usr/local/bin
COPY . .

ENV PYTHONUNBUFFERED=1
EXPOSE 8000

HEALTHCHECK --interval=30s --timeout=3s CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health/')" || exit 1
CMD ["gunicorn", "config.wsgi:application", "--bind", "0.0.0.0:8000", "--workers", "4"]

Docker 最佳实践

# 推荐做法 (GOOD practices)
- 使用具体的版本标签 (node:22-alpine, 而非 node:latest)
- 使用多阶段构建以最小化镜像大小
- 以非 root 用户运行
- 首先复制依赖文件（利用层缓存）
- 使用 .dockerignore 排除 node_modules, .git, tests
- 添加 HEALTHCHECK 指令
- 在 docker-compose 或 k8s 中设置资源限制

# 错误做法 (BAD practices)
- 以 root 用户运行
- 使用 :latest 标签
- 在一个 COPY 层中复制整个仓库
- 在生产镜像中安装开发依赖
- 在镜像中存储机密信息（应使用环境变量或机密管理器）

CI/CD 流水线 (CI/CD Pipeline)

GitHub Actions (标准流水线)

name: CI/CD

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm
      - run: npm ci
      - run: npm run lint
      - run: npm run typecheck
      - run: npm test -- --coverage
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: coverage
          path: coverage/

  build:
    needs: test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4
      - uses: docker/setup-buildx-action@v3
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      - uses: docker/build-push-action@v5
        with:
          push: true
          tags: ghcr.io/${{ github.repository }}:${{ github.sha }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

  deploy:
    needs: build
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    environment: production
    steps:
      - name: Deploy to production
        run: |
          # 平台特定的部署命令
          # Railway: railway up
          # Vercel: vercel --prod
          # K8s: kubectl set image deployment/app app=ghcr.io/${{ github.repository }}:${{ github.sha }}
          echo "Deploying ${{ github.sha }}"

流水线阶段 (Pipeline Stages)

PR 开启:
  代码扫描 (lint) → 类型检查 (typecheck) → 单元测试 → 集成测试 → 预览部署

合并到 main:
  代码扫描 (lint) → 类型检查 (typecheck) → 单元测试 → 集成测试 → 构建镜像 → 部署到预发环境 → 冒烟测试 → 部署到生产环境

健康检查 (Health Checks)

健康检查接口

// 简单健康检查
app.get("/health", (req, res) => {
  res.status(200).json({ status: "ok" });
});

// 详细健康检查 (用于内部监控)
app.get("/health/detailed", async (req, res) => {
  const checks = {
    database: await checkDatabase(),
    redis: await checkRedis(),
    externalApi: await checkExternalApi(),
  };

  const allHealthy = Object.values(checks).every(c => c.status === "ok");

  res.status(allHealthy ? 200 : 503).json({
    status: allHealthy ? "ok" : "degraded