How many different programs in the same process space hit so many common external services individual caching of names is not sufficient?
Article lists a bunch of fun with systemd running junk in containers that seem counterproductive to me. A lot of systemd stuff seems to be stuff useful on a laptop that ends up where it's really not wanted.
Local dns caching seems like a solution looking for a problem to me. I disable it whereever I can. I have local(ish) dns caches on the network. But not inside lxc containers or Linux hosts.