>A load balancer only works together with servers running the same code.
Uh - what?
>A load balancer balances traffic between servers
Correct.
> of the same service or mononlith
Incorrect.
Load balancers used to work solely at Layer 4, in which case you’d be correct that any 80/443 traffic would be farmed across servers that would necessarily need to run the same code base.
But modern load balancers (NGINX et al) especially in a service mesh / Kubernetes context, balance load at endpoint level. A high traffic endpoint might have dozens of pods running on dozens of K8s hosts having traffic routes to them by their ingress controller. A low traffic endpoint’s pod might only be running on few or one (potentially different) hosts.
The load balancer internally makes these decisions.
I hope this clears up your misunderstanding.