My router is a Synology RT2600ac; by default it runs dnsmasq. I recently replaced it with Synology’s full-fat DNS Service (it’s BIND); this broke DNS for my K3s cluster; here’s how I replaced that with ExternalDNS, making everything work again.

While debugging pod DNS problems, I discovered that CoreDNS allows customization by importing extra zone files from a config map. I’m going to use that to forward queries for k3s.differentpla.net to my custom CoreDNS instance.

I’ve got an extra instance of CoreDNS running in my cluster, serving *.k3s.differentpla.net, with LoadBalancer and Ingress names registered in it, and it’s working fine for queries to the cluster. It’s not working fine for queries inside the cluster. What’s up with that?

While messing around with my k3s cluster, I decided that I needed a DNS server. I tried the Synology DNS Server.

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