[cthalupa]

> We occasionally see getaddrinfo() calls fail claiming domains that we know exist at the failure time (b/c the records are completely static) don't exist.

That could be whatever resolvers you're hitting failing rather than an issue with Route 53 authoritative nameservers, though. The resolving DNS servers in EC2 are not actually part of Route 53, for example.

[deathanatos]

I'd think that would correspond to EAI_AGAIN or EAI_FAIL, whereas I'm pretty sure we're getting a EAI_NONAME.