for some reason, the current systemd-resolvd uses up 100% of one of my cores the entire time I'm building some stuff inside a vagrant VM. thanks systemd! no idea what you're doing, but it's not what you're supposed to be doing under that process (ie DNS lookups only).

disabled it and started using dnsmasq instead like before, problem has disappeared. systemd's codebase is so weirdly buggy in ways there's no visibility into, I just don't trust it.