In various embodiments, domain name system (DNS) servers are implemented on a content distribution network (CDN) infrastructure in order to facilitate centralized control of traffic steering. Each server appliance in the CDN infrastructure acts as both an authoritative DNS nameserver and a dynamic request proxy, and each such server appliance is assigned to one of multiple cloud computing system regions. The assignment of server appliances to cloud regions is based on latency measurements collected via client application probes and an optimization that minimizes an overall latency experienced by the client applications subject to constraints that the maximum traffic to each cloud region is less than a capacity constraint for that region, the maximum deviation of traffic to each cloud regions at any point in time is less than a given percentage, and the maximum deviation of traffic between direct and indirect paths is less than a given percentage.