Load balancers.
The host at a busy restaurant, seating each new guest at the emptiest table.
- 1
Clients learn a single address; how many servers stand behind it can change minute to minute.
- Station 3 has room — right this way.2
Like a restaurant host, it sends each request to a server with room to spare.
- Everyone alive back there?3
Health checks run on a timer, not on complaints — a sick server is found before a guest is sent to it.
- Skip station 2.4
A server that stops answering is pulled from rotation — nobody gets seated there.
- 5
Swamped? Add more identical servers and the load spreads across them all.
- I’m back!6
Scale out, route around failures — diners never notice the drama in the kitchen.
Semicolony semicolony.dev/eli5/load-balancer/comic