Re:Ask HN: DNS redundancy, how to do it right?
by LinuxBender on Wednesday February 08, 2023 @09:47AM
(#34708713)
If using the public DNS servers to resolve things then certainly have a few of them. 1.1.1.1 and 8.8.4.4 in case CF has problems.
If you have your own recursive servers in your datacenter then you can entirely control how many things are cached and how that cache behaves. Unbound is a really good option for this as it is fast, has controls around memory, threads, min/max TTL and you could even push your authoritative zones to the edge Unbound nodes if desired so that those records never expire. Some people take this a step further in their datacenter and have Unbound running on every instance to keep response latency low and handle upstream recursive fail-over better than the OS resolver does.
Another benefit to running your own caching servers is that you can purge records that you know are out of date during outages.
If you have your own recursive servers in your datacenter then you can entirely control how many things are cached and how that cache behaves. Unbound is a really good option for this as it is fast, has controls around memory, threads, min/max TTL and you could even push your authoritative zones to the edge Unbound nodes if desired so that those records never expire. Some people take this a step further in their datacenter and have Unbound running on every instance to keep response latency low and handle upstream recursive fail-over better than the OS resolver does.
Another benefit to running your own caching servers is that you can purge records that you know are out of date during outages.