Request are not distributed across their worker process - node.js

Question

I was just experimenting worker process hence try this:
const http = require("http");
const cluster = require("cluster");
const CPUs = require("os").cpus();
const numCPUs = CPUs.length;
if (cluster.isMaster) {
console.log("This is the master process: ", process.pid);
for (let i = 0; i < numCPUs; i++) {
cluster.fork();
}
cluster.on("exit", (worker) => {
console.log(`worker process ${process.pid} has died`);
console.log(`Only ${Object.keys(cluster.workers).length} remaining...`);
});
} else {
http
.createServer((req, res) => {
res.end(`process: ${process.pid}`);
if (req.url === "/kill") {
process.exit();
}
console.log(`serving from ${process.pid}`);
})
.listen(3000);
}
I use loadtest to check "Are Request distributed across their worker process?" But I got same process.pid
This is the master process: 6984
serving from 13108
serving from 13108
serving from 13108
serving from 13108
serving from 13108
...
Even when I kill one of them, I get the same process.pid
worker process 6984 has died
Only 3 remaining...
serving from 5636
worker process 6984 has died
Only 2 remaining...
worker process 6984 has died
Only 1 remaining...
How I am getting same process.pid when I killed that? And Why my requests are not distributed across their worker process?
Even when I use pm2 to test cluster mood using:
$ pm2 start app.js -i 3
[PM2] Starting app.js in cluster_mode (3 instances)
[PM2] Done.
┌────┬────────────────────┬──────────┬──────┬───────────┬──────────┬──────────┐
│ id │ name │ mode │ ↺ │ status │ cpu │ memory │
├────┼────────────────────┼──────────┼──────┼───────────┼──────────┼──────────┤
│ 0 │ app │ cluster │ 0 │ online │ 0% │ 31.9mb │
│ 1 │ app │ cluster │ 0 │ online │ 0% │ 31.8mb │
│ 2 │ app │ cluster │ 0 │ online │ 0% │ 31.8mb │
└────┴────────────────────┴──────────┴──────┴───────────┴──────────┴──────────┘
for loadtest -n 50000 http://localhost:3000 I check pm2 monit:
$ pm2 monit
┌─ Process List ───────────────────────────────────────────────────┐┌── app Logs ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│[ 0] app Mem: 43 MB CPU: 34 % online ││ │
│[ 1] app Mem: 28 MB CPU: 0 % online ││ │
│[ 2] app Mem: 27 MB CPU: 0 % online ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
│ ││ │
└──────────────────────────────────────────────────────────────────┘└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
┌─ Custom Metrics ─────────────────────────────────────────────────┐┌─ Metadata ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Heap Size 20.81 MiB ││ App Name app │
│ Heap Usage 45.62 % ││ Namespace default │
│ Used Heap Size 9.49 MiB ││ Version N/A │
│ Active requests 0 ││ Restarts 0 │
└──────────────────────────────────────────────────────────────────┘└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
left/right: switch boards | up/down/mouse: scroll | Ctrl-C: exit To go further check out https://pm2.io/
But surprisingly, app1 and app2 never hit any request as well as it didn't show any app log.
Update 1
I still couldn't figure out any solution. If any further query need please ask for that. I faced that issue first time. That's why maybe I was unable to represent where the exact problem occurring.
Update 2
After getting some answer I try to test it again with a simple node server:
Using pm2 without any config:
Using config suggested from #Naor Tedgi's answer:
Now the server is not running at all.

Answer 1

I got this
Probably it is OS related,I am on Ubuntu 20.04.

Answer 2

you don't have cluster mode enabled if you want to use pm2 as load balancer you need to add
exec_mode cluster
add this config file name it config.js
module.exports = {
apps : [{
script : "app.js",
instances : "max",
exec_mode : "cluster"
}]
}
and run pm2 start config.js
then all CPU usage will divide equally
tasted on
os macOS Catalina 10.15.7
node v14.15.4

Answer 3

Not sure why, but it seems that for whatever reason cluster doesn't behave on your machine the way it should.
In lieu of using node.js for balancing you can go for nginx then. On nginx part it's fairly easy if one of the available strategies is enough for you: http://nginx.org/en/docs/http/load_balancing.html
Then you need to make sure that your node processes are assigned different ports. In pm2 you can either use https://pm2.keymetrics.io/docs/usage/environment/ to either manually increment port based on the instance id or delegate it fully to pm2.
Needless to say, you'll have to send your requests to nginx in this case.