Docker与Sequelize连接持续出现ENOTFOUND错误求助

我查过Stack Overflow帖子和谷歌搜索，还是一直碰到相同错误。

操作过程 #

1. 启动MySQL容器，运行正常：

docker run --rm  --name mysql-container -e MYSQL_ROOT_PASSWORD=password -d -p 3305:3306 mysql:latest

容器状态：

CONTAINER ID   IMAGE          COMMAND                   CREATED          STATUS          PORTS                               NAMES
5980ecc42a28   mysql:latest   "docker-entrypoint.s…"   36 seconds ago   Up 35 seconds   33060/tcp, 0.0.0.0:3305->3306/tcp   mysql-container

2. 编写Dockerfile构建Node镜像，构建过程无问题：

FROM node

WORKDIR /app

COPY package.json .

RUN npm install 

COPY . .

EXPOSE 80

CMD [ "node", "app.js" ]

构建命令：

docker build -t goals-node .

3. 运行Node镜像时，持续出现ENOTFOUND错误。

相关配置 #

app.js #

const fs = require("fs");
const path = require("path");

const express = require("express");
const Sequelize = require("sequelize");
const bodyParser = require("body-parser");
const morgan = require("morgan");
const dotenv = require("dotenv");

dotenv.config({ path: "./env/mysql.env" });

const Goal = require("./models/goal");

const app = express();

const sequelize = new Sequelize(
  process.env.MYSQL_DATABASE,
  process.env.MYSQL_USER,
  process.env.MYSQL_ROOT_PASSWORD,
  {
    port: process.env.MYSQL_PORT,
    host: "mysql",
    dialect: "mysql",
    logging: false,
    pool: {
      max: 5,
      min: 0,
      acquire: 30000,
      idle: 10000,
    },
  }
);

env/mysql.env #

MYSQL_DATABASE=docker_test
MYSQL_ROOT_PASSWORD=itspassword // its not real password
MYSQL_PASSWORD=itspassword
MYSQL_DATA_DIR=./mysql_data
MYSQL_USER=root
MYSQL_PORT=3305

package.json #

{
  "name": "backend",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "errorTest",
  "license": "ISC",
  "dependencies": {
    "body-parser": "^1.19.0",
    "express": "^4.17.1",
    "dotenv": "^16.3.2",
    "morgan": "^1.10.0",
    "mysql2": "^3.7.1",
    "sequelize": "^6.35.2",
    "sequelize-cli": "^6.6.2"
  }
}

goal.js #

const Sequelize = require("sequelize");

module.exports = class Goal extends Sequelize.Model {
  static init(sequelize) {
    return super.init(
      {
        text: {
          type: Sequelize.STRING,
        },
      },
      {
        sequelize,
        modelName: "Goals",
        tableName: "goals",
      }
    );
  }
  static associate(db) {}
};

错误信息 #

myComputer@myComputer-MacBookPro backend % docker run --name goals-backend --rm  goals-node
80 port is ready
HostNotFoundError [SequelizeHostNotFoundError]: getaddrinfo ENOTFOUND mysql
    at ConnectionManager.connect (/app/node_modules/sequelize/lib/dialects/mysql/connection-manager.js:96:17)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async ConnectionManager._connect (/app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:222:24)
    at async /app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:174:32
    at async ConnectionManager.getConnection (/app/node_modules/sequelize/lib/dialects/abstract/connection-manager.js:197:7)
    at async /app/node_modules/sequelize/lib/sequelize.js:305:26
    at async Sequelize.authenticate (/app/node_modules/sequelize/lib/sequelize.js:457:5)
  parent: Error: getaddrinfo ENOTFOUND mysql
      at GetAddrInfoReqWrap.onlookupall [as oncomplete] (node:dns:118:26) {
    errno: -3008,
    code: 'ENOTFOUND',
    syscall: 'getaddrinfo',
    hostname: 'mysql',
    fatal: true
  },
  original: Error: getaddrinfo ENOTFOUND mysql
      at GetAddrInfoReqWrap.onlookupall [as oncomplete] (node:dns:118:26) {
    errno: -3008,
    code: 'ENOTFOUND',
    syscall: 'getaddrinfo',
    hostname: 'mysql',
    fatal: true
  }
}

我试过调整app.js里的Sequelize配置，但错误还是一直出现，问题出在哪？

问题出在三个核心点：容器网络隔离、端口配置错误、密码不匹配。

1. 容器网络隔离问题 #

默认情况下，Docker容器处于独立的网络命名空间，Node容器无法通过mysql主机名解析到MySQL容器，必须将两个容器放到同一个Docker网络中。

解决步骤（推荐自定义网络） #

• 创建自定义网络：

docker network create goals-network

• 重新启动MySQL容器，加入该网络，同时指定自动创建目标数据库（避免后续数据库不存在的错误）：

docker run --rm --name mysql-container --network goals-network -e MYSQL_ROOT_PASSWORD=password -e MYSQL_DATABASE=docker_test -d -p 3305:3306 mysql:latest

• 运行Node容器时加入同一个网络：

docker run --name goals-backend --rm --network goals-network goals-node

2. 端口配置错误 #

容器之间通信使用的是容器内部端口，而非主机映射端口。MySQL容器内部端口为3306，你在env/mysql.env里配置的MYSQL_PORT=3305是主机映射端口，需要修改为：

MYSQL_PORT=3306

3. 密码不匹配 #

你启动MySQL容器时设置的MYSQL_ROOT_PASSWORD=password，与env/mysql.env里的MYSQL_ROOT_PASSWORD=itspassword不一致。要么修改MySQL启动命令的密码为itspassword，要么把env里的密码改成password。

完成以上修改后，Node容器即可正常连接到MySQL容器。

内容的提问来源于stack exchange，提问作者brgndy