CoreDNS

Override DNS resolver for a domain

apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns-custom
  namespace: kube-system
data:
  spacemule.server: |
    spacemule.net:53 {
      errors
      cache 600
      forward . 10.42.42.42
    }

Create as many keys as necessary. To add to the main config section, change the key’s suffix from .server to .include.