Load balancer
termnetworkingcloud
A device or service that accepts client traffic on one address and distributes it across a set of backend servers, tracking which of them are usable.
Its algorithm is the least consequential part of its configuration. What determines behaviour in production is the health check that defines which servers exist, the persistence rule that pins clients, and the drain and warm-up behaviour when the set changes. It is also in the path of everything, so it hides individual server failures from users and from you - which is why per-member metrics matter more than the pool average, and why a pool that looks healthy can contain one member serving errors quickly enough to attract extra traffic.
Also known as: adc, application delivery controller, pool, vip, backend pool