CoreDNS

wikipedia:CoreDNS (2019) DNS and Service discovery

• https://coredns.io/
• Corefile
• kubectl describe configmap coredns -n kube-system

kubectl -n kube-system -l=k8s-app=kube-dns get pods
NAME                      READY   STATUS    RESTARTS   AGE
coredns-f47955f89-7ntw4   0/1     Pending   0          3h37m
coredns-f47955f89-sl79r   0/1     Pending   0          3h37m

EKS

Terraform:

 cluster_addons = {
   coredns = {
     preserve    = true
     most_recent = true

     timeouts = {
       create = "25m"
       delete = "10m"
     }
   }
   kube-proxy = {
     most_recent = true
   }
   vpc-cni = {
     most_recent = true
   }
   aws-ebs-csi-driver = {
     most_recent = true
   }
 }

Related: Terraform EKS module official usage example

Protocols

• dns:// for plain DNS (the default if no scheme is specified).
• tls:// for DNS over TLS, see RFC 7858.
• https:// for DNS over HTTPS, see RFC 8484.
• grpc:// for DNS over gRPC

Errors

• Error: waiting for EKS Add-On
• Bad response statusCode (422)

Versions

• 2022-01-24 1.8.7 https://coredns.io/2021/12/09/coredns-1.8.7-release/

• 2020/06/15 1.7.0 https://coredns.io/2020/06/15/coredns-1.7.0-release/

Related terms

• DNS: kube-dns
• kube-system namespace
• Kubernetes 1.13 (December 2018)
• kubeadm config images pull
• Miek Gieben
• EKS: kubectl get service kube-dns -n kube-system
• kubectl cluster-info
• dnsPolicy:
• EKS add-ons: kube-dns, kube-proxy
• kubectl get serviceaccounts
• Kubernetes DNS
• brew install --cask orbstack
• kubectl patch configmap coredns -n kube-system --type=merge -p

Activities

• https://aws.amazon.com/premiumsupport/knowledge-center/eks-dns-failure/
• CKA 1.28: Know how to configure and use CoreDNS

See also

• CoreDNS, kube-dns, Know how to configure and use CoreDNS, Corefile
• Kubernetes networking networking.k8s.io: network policies, Network Policy Providers, CNI, Calico, flannel, Service mesh, Istio, kube-proxy, coredns, AWS VPC CNI: vpc-cni, Kubernetes: Ingress controllers, IPVS, ServiceTypes: LoadBalancer, ClusterIP, NodePort, ExternalName, Endpoints, EndpointSlices, Kubernetes DNS, svc.cluster.local, Weave Net, Cilium, Traefik, GKE Dataplane V2

https://coredns.io/