我想創建一個 nginx docker container 來作為 udp 負載平衡，轉發到另一個 有 udp server 的 ndoe docker container。

之後用 udp client 向 nginx container 發信息，但 udp server 一直没有收到信息，nginx、ndoe container 也没有錯誤信息。

不知道哪裡出了問題，想請大家幫忙看一下配置和步驟。

配置和步驟。

1. 創建一個 docker network

docker network create udp_proxy

2.創建 udp 負載平衡 image

docker build -t mailbox_proxy .

# nginx Dockerfile
FROM nginx:stable-alpine
COPY udp-load‑balanced.conf /etc/nginx/conf.d/
COPY nginx.conf /etc/nginx/

# udp-load‑balanced.conf
upstream dns_upstream  {
  server mailbox_1:80 fail_timeout=60s;
}

server {
  listen 53 udp;
  proxy_pass dns_upstream;
  proxy_timeout 1s;
  proxy_responses 1;
  error_log /var/log/nginx/udp-dns-error.log notice;
}

# nginx.conf
user  nginx;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}

http {
  include       mime.types;
  default_type  application/octet-stream;
  sendfile        on;
  server {
    listen 80;
    server_name  localhost;

    location / {
      root   html;
      index  index.html index.htm;
    }
  }
}

stream {
  include /etc/nginx/conf.d/udp-load‑balanced.conf;
}

2.創建 udp server image

docker build -t mailbox .

# udp server Dockerfile
FROM node:lts-alpine3.16
RUN mkdir /mailbox
WORKDIR /mailbox
COPY index.js /mailbox
COPY package.json /mailbox
CMD ["npm", "run", "start"]

// index.js
// udp server
const dgram = require('dgram');

function main() {
  const server = dgram.createSocket('udp4');
  const prot = '80';

  server.on('error', (err) => {
    console.log(`server error:\n${err.stack}`);
    server.close();
  });

  server.on('message', (msg, rinfo) => {
    console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
  });

  server.on('listening', () => {
    const address = server.address();
    console.log(`server listening ${address.address}:${address.port}`);
  });

  server.bind(prot);
}

main();

// package.json
{
  "name": "mailbox",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "node index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

4.創建 udp 負載平衡 container

docker run -d -p 8080:80 -p 53:53 --name mailbox_proxy --network udp_proxy mailbox_proxy

5. 創建 udp server container

docker run -d --name mailbox_1 --network udp_proxy mailbox

6.udp client 向 nginx container 發信息

// udp client
const dgram = require('node:dgram');
const { Buffer } = require('node:buffer');

const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 53, calhost', (err) => {
  client.close();
});

解決方法

問題出在步驟 4 我開的 prot 是 tcp，因此udp 負載平衡一直没有收到 udp 信息，
把步驟 4 的指令改為下面就可以了。

docker run -d -p 8080:80 -p 53:53/udp --name mailbox_proxy --network udp_proxy mailbox_proxy