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How to get kubernetes to add all its internal dns entries to your own dns server (lemmy.zip)

submitted 1 week ago by [email protected] to c/[email protected]

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By this I mean, I have a powerdns server running in my cluster, I would like Kubernetes to add/update dns entries in my dns server to reflect all services or any domains that would be used within the cluster, this is to fix a current issue I am having, and for general control and centralization purposes.

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[–] [email protected] 2 points 6 days ago (9 children)

Well, its kube-dns, and it simply, does not work, more specifically, it cannot resolve any external domains, I think it can resolve internal domains but I doubt thats working, but mainly it cant resolve external domains. I posted about it, here: https://lemmy.zip/post/36964791

Recently, it was fixed because I found the correct endpoint, and uhh, now it stopped working, I updated the endpoint to the newer one, but it went back to the original issue detailed in that post.

[–] [email protected] 2 points 6 days ago* (last edited 6 days ago) (8 children)

I'd be surprised if it's still kubedns.. the service name is still kubedns, but there will probably be CoreDNS pods behind it. To debug this, you should first ensure that you can resolve DNS by directly pointing to an external DNS server from a pod, and then from the node if that fails. eg. dig @1.1.1.1 google.com, or host google.com 1.1.1.1. It might be a routing/firewall/nat issue more than DNS, and this would help track that down.

[–] [email protected] 1 points 5 days ago (7 children)

https://pastebin.com/RhU5xtma I cant access any external address including dns servers, so, there is no firewall running on my pi (the master node), I can set the nameserver to be 1.1.1.1 in the pods config and iirc that works, but inside the pod, it doesn't work, so how do i fix this? You probably need more information so i can share. I am running calico as my CNI

[–] [email protected] 1 points 5 days ago* (last edited 5 days ago) (1 children)

Do you have any NetworkPolicies configured that could block ingress (to kubedns, in kube-system) or egress (in your namespace) ? If any ingress or egress networkpolicy matches a pod, it flips from AllowByDefault to DenyByDefault.

You should also do kubectl get service and kubectl get endpoints in kube-system, as well as kubectl get pods | grep -i dns

[–] [email protected] 1 points 5 days ago

spiderunderurbed@raspberrypi:~/k8s $ kubectl get networkpolicy -A
No resources found
spiderunderurbed@raspberrypi:~/k8s $

No networkpolicies.

spiderunderurbed@raspberrypi:~/k8s $ kubectl get pods -A | grep -i dns
default                      pdns-admin-mysql-854c4f79d9-wsclq                         1/1     Running            1 (2d22h ago)    4d9h
default                      pdns-mysql-master-6cddc8cd54-cgbs9                        1/1     Running            0                7h49m
kube-system                  coredns-ff8999cc5-hchq6                                   1/1     Running            1 (2d22h ago)    4d11h
kube-system                  svclb-pdns-mysql-master-1993c118-8xqzh                    3/3     Running            0                4d
kube-system                  svclb-pdns-mysql-master-1993c118-whf5g                    3/3     Running            0                124m
spiderunderurbed@raspberrypi:~/k8s $

Ignore powerdns, its just extra stuff, but yeah coredns is running

spiderunderurbed@raspberrypi:~/k8s $  kubectl get endpoints  -n kube-system
NAME             ENDPOINTS                                              AGE
kube-dns         172.16.246.61:53,172.16.246.61:53,172.16.246.61:9153   4d11h
metrics-server   172.16.246.45:10250                                    4d11h
traefik          <none>                                                 130m
spiderunderurbed@raspberrypi:~/k8s $

^ endpoints and services:

spiderunderurbed@raspberrypi:~/k8s $ kubectl get svc -n kube-system
NAME             TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
kube-dns         ClusterIP      10.43.0.10      <none>        53/UDP,53/TCP,9153/TCP       4d11h
metrics-server   ClusterIP      10.43.67.112    <none>        443/TCP                      4d11h
traefik          LoadBalancer   10.43.116.221   <pending>     80:31123/TCP,443:30651/TCP   131m
spiderunderurbed@raspberrypi:~/k8s $

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