Example clustering mode in Node.js

cluster_app.js

const express = require("express");
const cluster = require("cluster");
const os = require("os");

const PORT = process.env.PORT || 3001;

// Replace with your logger
const logger = console;

// If the current is master, create the fork for all the cpus
if (cluster.isMaster) {
  for (let i = 0; i < os.cpus().length; i++) {
    cluster.fork();
  }

  cluster.on("exit", (worker) => {
    logger.error(`Worker has exit ${worker.process.pid}, creating another...`);
    cluster.fork();
  });
} else {
  const app = express();

  // Endpoint for health check API
  app.get("/health", (_, res) => {
    res.status(200).json({ message: "ok", process: process.pid });
  });

  app.listen(PORT, () => {
    logger.info(`API listen in ${PORT} - process ${process.pid}`);
  });
}