健康检查

2024年07月18日

柏拉文

越努力，越幸运

一、认识

---

基于 healthCheck 指令来检查健康状态

二、语法

---

services:
    serviceA:
        image: imageA:Tag 
    serviceB:
        image: imageB:Tag 
        depends_on:
            - serviceA  // serviceA 启动成功后，启动B , 不管 serviceA 服务是否有效
        healthcheck:
            test: ["CMD", "curl", "-f", "http://localhost:3000"]
            interval: 30s
            timeout: 3s
            retries: 3
    serviceC:
        image: imageC:Tag,
        depends_on:
            serviceB:
                condition: service_healthy // 当 serviceB 服务处于 healthy 时， 才可以启动 serviceC

三、测试

---

3.1 Node 健康检查

index.js

const http = require("http");
const PORT = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader("Content-Type", "text/plain");
  res.end(`Hello from Node.js`);
});

server.listen(PORT, () => {
  console.log(`Server running at port ${PORT}`);
});

Dockerfile

FROM node:latest
WORKDIR /app
COPY . /app 
EXPOSE 3000
CMD ["node","index.js"]

docker-compose.yml

services:
  node1:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: node1
    ports:
      - 3000:3000
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000"]
      interval: 30s
      timeout: 3s
      retries: 3
    networks:
      - node1
  node2:
    image: node:latest
    container_name: node2
    depends_on:
      node1:
        condition: service_healthy
    networks:
      - node1

networks:
  node1:
    driver: bridge