Consider reducing DNS in favour of coreDNS

[Jackbennett]

Hi, Hopefully not insulting but have you considered reducing the scope of problems to cover by unloading the DNS work to CoreDNS.

I have dnsmasq DHCP + coredns setup that works well, dnsmasq purely handles reverse DNS for its DHCP range since I don't see how coredns can do that (you could template responses but that doesn't check there's really a dhcp lease.).

I've had an eye on gravity to replace dnsmasqs DHCP as running multiple coreDNS is no problem. Failover dhcp is largely not well solved until you've done it. DNS can be replicated so well I worry coupling it to etcd. I'm trying to find out more actually what happens around etcd and how it behaves when quorum is lost.