With "RcodeZero Anycast DNS" we provide Authoritative DNS for millions of zones. We used to use PowerDNS Authoritative Nameserver with Database Backend, which is a great tool for hosting millions of zones. But the ease of provisioning comes with the drawback of poor performance for random subdomain queries. In the last few years the number of these random subdomain queries increased from once a month to 24x7. To handle the query load of such random subdomain "attacks", we opted for Knot DNS, which has the reputation of fastest open source name server. At the same moment, luckily catalog zones popped up and we decided to use them for provision the zones on Knot. Although everthing sounded straight forward, migrating from PowerDNS to Knot was a long way with plenty of pitfalls. And even as we did it, operating Knot is very different than operating PowerDNS.
This talk will discuss the reason to migrate to Knot, the migration problems and how we solved them with the help of the Knot developers. We will also talk about unsolved problems and alternative solutions.