It's hilarious how many of these stories there are. I remember debugging a DNS issue on an embedded system; the resolv.conf changed but the program continued trying the old DNS server. Turns out GLIBC will read the resolv.conf once on startup and never again after (unless specifically invalidated). Except most people will never notice this behavior because (1) most distributions carry a patch from 2004 that reloads it transparently or (2) use libraries that just always invalidate it, just to be sure.

This stupidity surfaces everywhere; here is a Go bug report for it:

https://github.com/golang/go/issues/21083