Try running 15k containers, dnsmasq and powerdns fall over pretty fast. I have to run a BIND cluster of 3 machines to support the days when I am running at-scale testing of software (low load, but high instance count is a better fit for my work these days). I use 4th gen i7 machines as DNS resolver/caching servers, and using dnsmasq on the same machines I start to have issues around 400 clients, massive latency, broken responses, tons of crazy stuff. One BIND instance and I can get to about 7500 clients before it starts to get squeezed.

The difference is huge in other ways, though. Configuration, operations, and maintenance of the BIND cluster is 20 fold more involved, and when things break, they can break in really confusing ways. Such is the world of computing though, the better something performs, the more places it has where you can mess it up.