Adding a extra DNS pod how to configure and handle

Question

I want to add a extra DNS server as a pod (internal for the other pods).

Kube-DNS works fine, the pods can resolve the short-names of the others and could find the extra dns-pod by : #>host dns

So far so good. The resolve.conf on all of the pods have only the coredns entry (namesever CLUSTER_IP).

I I manually add a second name server to the resolve.conf but it do not work. Now I thought about a extra rule in the Kube-DNS to forward requests to the dns-pod. But have no idea if this is the right way to go. Furthermore I do not know the ip of the dns-pod during auto-creation of the complete setup (terraform).

Would be nice to receive some tips how this should be done.

best

Can you explain what you are trying to achieve by adding the extra DNS server? CoreDNS can be configured to do a lot of things, it probably supports whatever you are trying to add. — Matt
The other pods should add extra domains to the dns-pod (pod1.domain=> external ip, pod1-internal.domain=> internal ip and so on) . But before they have to resolve the dos-pod to know were it is. — mickmack
Ok.. would need a more detailed explanation to see if coredns could manage the service for you, but it can at least do the forwarding. — Matt

Matt Matt · Accepted Answer · 2019-08-23T11:19:01

Setup a Service for your DNS pod, specifying a cluster IP in your allocated cluster service range.

apiVersion: v1
kind: Service
metadata:
  name: my-dns-service
spec:
  selector:
    app: dns-app
  ports:
    - protocol: UDP
      port: 53
      targetPort: 53
    - protocol: TCP
      port: 53
      targetPort: 53
  clusterIP: 10.233.8.8

Configure CoreDNS to forward your custom domains to that cluster IP.

Modify the coredns ConfigMap to include the forward plugin

    domain:53 {
        errors
        cache 30
        forward . 10.233.8.8
    }
    internal.domain:53 {
        errors
        cache 30
        forward . 10.233.8.8
    }

Adding a extra DNS pod how to configure and handle

1 Answers