主机可连接MySQL Docker容器，Node容器无法连接的问题排查

问题详情 #

主机可正常连接Docker容器内的MySQL服务，但同网络下的Node容器无法连接，持续出现ETIMEDOUT错误。单独运行MySQL容器时，主机本地执行Node代码（host设为127.0.0.1）可成功连接。

相关配置 #

docker-compose.yml #

version: '3.9'
services:
  mysql:
    image: mysql:8.0
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    environment:
      MYSQL_DATABASE: 'admindb'
      MYSQL_USER: 'admin'
      MYSQL_PASSWORD: 'secretpassword'
      MYSQL_ROOT_PASSWORD: 'someverysecretpassword'
    ports:
      - '3306:3306'
      - '33060:33060'
    volumes:
      - ./db:/var/lib/mysql
    networks:
      - adminnet
  app:
    image: "node:latest"
    depends_on:
      - mysql
    user: "node"
    restart: unless-stopped
    working_dir: /home/app
    environment:
      NODE_ENV: production
    volumes:
      - ${PWD}/../:/home/app
    ports:
      - '8081:8081'
    command: "npm start"
    networks:
      - adminnet
volumes:
  db:
  data:

networks:
  adminnet:

app.js #

const { Sequelize } = require('sequelize');

const sequelize = new Sequelize('admindb', 'admin', 'secretpassword', {
    host: 'mysql',
    port: 3306,
    dialect: 'mysql',
});

sequelize
  .authenticate()
  .then(() => {
    console.log('Connection has been established successfully.');
  })
  .catch(err => {
    console.error('Unable to connect to the database:', err);
  });

错误日志 #

containers-app-1    | Unable to connect to the database: ConnectionError [SequelizeConnectionError]: connect ETIMEDOUT
containers-app-1    |     at ConnectionManager.connect (/home/app/node_modules/sequelize/lib/dialects/mysql/connection-manager.js:102:17)
containers-app-1    |     at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
containers-app-1    |     at async ConnectionManager._connect (/home/app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:220:24)
containers-app-1    |     at async /home/app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:174:32
containers-app-1    |     at async ConnectionManager.getConnection (/home/app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:197:7)
containers-app-1    |     at async /home/app/node_modules/sequelize/lib/sequelize.js:301:26
containers-app-1    |     at async Sequelize.authenticate (/home/app/node_modules/sequelize/lib/sequelize.js:453:5) {
containers-app-1    |   parent: Error: connect ETIMEDOUT
containers-app-1    |       at Connection._handleTimeoutError (/home/app/node_modules/mysql2/lib/connection.js:189:17)
containers-app-1    |       at listOnTimeout (node:internal/timers:564:17)
containers-app-1    |       at process.processTimers (node:internal/timers:507:7) {
containers-app-1    |     errorno: 'ETIMEDOUT',
containers-app-1    |     code: 'ETIMEDOUT',
containers-app-1    |     syscall: 'connect',
containers-app-1    |     fatal: true
containers-app-1    |   },
containers-app-1    |   original: Error: connect ETIMEDOUT
containers-app-1    |       at Connection._handleTimeoutError (/home/app/node_modules/mysql2/lib/connection.js:189:17)
containers-app-1    |       at listOnTimeout (node:internal/timers:564:17)
containers-app-1    |       at process.processTimers (node:internal/timers:507:7) {
containers-app-1    |     errorno: 'ETIMEDOUT',
containers-app-1    |     code: 'ETIMEDOUT',
containers-app-1    |     syscall: 'connect',
containers-app-1    |     fatal: true
containers-app-1    |   }
containers-app-1    | }

排查方案 #

• 确保MySQL服务完全就绪：depends_on仅保证容器启动顺序，不代表MySQL服务已可用。可在Node服务中添加连接重试逻辑，或使用wait-for-it等工具等待3306端口开放后再启动应用。
• 验证网络连通性：进入Node容器安装测试工具，执行apt update && apt install -y telnet，然后运行telnet mysql 3306，若无法连接则说明网络存在问题。
• 检查MySQL绑定地址：MySQL默认可能仅绑定127.0.0.1，需修改为允许所有地址连接。在docker-compose的mysql服务command中添加--bind-address=0.0.0.0，修改后重启容器。
• 确认数据库用户权限：登录MySQL容器，执行GRANT ALL ON admindb.* TO 'admin'@'%'; FLUSH PRIVILEGES;，确保admin用户允许从任意主机（包括容器网络）连接。
• 排查卷挂载干扰：若本地./db目录存在旧的MySQL数据，可能残留旧配置。临时注释掉volumes中的- ./db:/var/lib/mysql，重新创建容器测试是否恢复正常。

内容的提问来源于stack exchange，提问作者Erik van de Ven