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I am running a AKS cluster and Microsoft Azure is not able resolve its own service(dev.azure.com) in its backbone.
I am not using any costume DNS of my own use AKS provided once only.
To isolate the issue i can a container with nslookup and found once in 10 time it will fail to resolve dev.azure.com and this make it NOT THE Best choice for VCS (central repo server with code that need to be in available in HA mode)
Below is output :
root@tmp-shell:/# nslookup dev.azure.com
Server: 10.0.0.10
Address: 10.0.0.10#53
Name: dev.azure.com
Address: 13.107.42.20
root@tmp-shell:/# nslookup dev.azure.com
Server: 10.0.0.10
Address: 10.0.0.10#53
** server can't find dev.azure.com: SERVFAIL
root@tmp-shell:/# nslookup dev.azure.com
Server: 10.0.0.10
Address: 10.0.0.10#53
** server can't find dev.azure.com.gsoaylwixxxxxnhrmmd3k1rfnb.frax.internal.cloudapp.net: SERVFAIL
dial tcp: lookup dev.azure.com on 10.0.0.10:53: server misbehaving"
dial tcp: lookup dev.azure.com on DNS_IP:53: server misbehaving"
Error message from logs
error resolving repo revision: rpc error: code = Unknown desc = Get "https://mycorp@dev.azure.com/mycorp/manifests/_git/manifests/info/refs?service=git-upload-pack": dial tcp: lookup dev.azure.com on 10.0.0.10:53: server misbehaving"
Kubernetes version:1.26.6
Type (plugin): Azure CNI
DNS service IP: 10.0.0.10
Network policy: None
Error log is same be it private or public cluster.
kubectl logs -f -l k8s-app=kube-dns -n kube-system
[ERROR] plugin/errors: 2 dev.azure.com. AAAA: read udp 10.244.0.16:35510->10.215.4.10:53: i/o timeout
[ERROR] plugin/errors: 2 dev.azure.com. A: read udp 10.244.0.16:41869->10.215.4.12:53: i/o timeout
[ERROR] plugin/errors: 2 dev.azure.com. A: read udp 10.244.0.16:52191->10.215.4.10:53: i/o timeout
[INFO] 10.244.0.19:58400 - 31861 "A IN dev.azure.com.3hrulajbi5nxxxxxxxnan5g.ax.internal.cloudapp.net. udp 94 false 1232" - - 0 2.000599712s
If you would ask what is status of core-dns, see blow
coredns-76b9877f49-cm2sv 1/1 Running 0
coredns-76b9877f49-d2bjg 1/1 Running 0
coredns-autoscaler-59b9d8bbb4-p5kp4 1/1 Running 0
coredns config
kubectl describe cm coredns -n kube-system
Name: coredns
Namespace: kube-system
Labels: addonmanager.kubernetes.io/mode=Reconcile
k8s-app=kube-dns
kubernetes.io/cluster-service=true
Annotations:
Hello Rajesh
Firstly, apologies for the delay in responding here and any inconvenience this issue may have caused.
This issue needs deeper investigation. Support team will be able to check and help on this. I would recommend you to open a azure support case.
If you don't have a support plan enabled on your subscription, please let me know I can assist you in opening a support case.
Hello Rajesh,
Were you able to solve this?
Are you using somesort of a UDR? is this a clean AKS installation?
In my case i deployed one of the app deployed that have updated coredns cm in AKS with some custom dns entry's that was causing this in my case. Post its was removal it stated to wok as expected.
And no i wan't using UDR.
Any one else having this issue should check below first.
$ kubectl describe cm coredns -n kube-system
Thanks for responding and good to close this.