Trying to understand your setup: this seems like a split-horizon DNS, where app.example.com is only visible from your internal network (or Tailnet), right?

If so - I explained my similar setup in this comment; in short, my internal DNS works perfectly because the internal DNS server has a static “service IP” (handled by kube-proxy); if my currently-running pod breaks, k8s will simply spawn a new one and the DNS server IP won’t even have to change - meaning, the internal DNS zone continues to be served no matter which node breaks (it’ll even survive multiple node failures).

But the external DNS is different and I can’t simply plug in a “fake loadbalancer IP” there… (there are valid workarounds but they either are incredibly finicky or I have to spend an obscene amount of money to implement them)