Lesson 21 — Round-robin revisited

Skip servers that are down

Plain round-robin keeps sending requests to a server even after it crashes. A smarter balancer skips servers that failed their health check. Filter the healthy ones first, then rotate through only those.

const open = shops.filter((s) => s.isOpen);

Note: real DevOps tools (CI servers, load balancers, Docker, Kubernetes) cannot run in your browser, so this exercise is a small plain-JS simulation of the logic those tools use.

Why it matters: users never get routed to a dead machine.