DNS load balancing steers clients by returning different DNS answers for the same hostname. The authoritative DNS service can pick an address based on health, weight, geography, latency, or failover state.

Because it works before any TCP, TLS, or HTTP connection opens, DNS is well suited to regional routing, gradual migrations, and disaster recovery. It is also coarse: answers get cached by resolvers and clients, and DNS has no view of per-request load on the servers it points to.