GSLB Failover for AWS ELBs

We just launched the first phase of a low-latency ad app in three AWS regions, us-east-1, us-west-1, and eu-west-1. One DNS record distributes load across all three via GSLB. In case you don’t know, this just means that when a client asks the authoritative nameserver where it is, the nameserver asks where the client is. If they’re in California, they go to us-west-1. If they’re in europe, they go to eu-west-1. Asia, it depends. You can configure what goes where, even if it doesn’t make sense. Now that we’re load balancing everywhere, what about failover? Continue reading