node-test/app.js

const express = require('express');

const PORT = 8900;
const HOST = '0.0.0.0';

const instanceNumber = Math.floor(Math.random() * 101);

const app = express();

app.get('/', (req, res) => {
    var ip = req.headers['x-forwarded-for'] || req.ip;
    res.send(`node-test instance ${instanceNumber}, your IP: ${ip}`);
});

app.listen(PORT, HOST, () => {
    console.log(`Server started on http://${HOST}:${PORT}`);
});