IssueTracker

Problem you have encountered:

A workload that is deployed in a GKE Windows nodepool encounters intermittent DNS resolution issue.

What you expected to happen:

Robust DNS resolution and no DNS failures.

Steps to reproduce:

• Create a GKE cluster with a Windows nodepool.
• Deploy the below Windows Workload:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: win-webserver
  name: win-webserver
spec:
  replicas: 1
  selector:
    matchLabels:
      app: win-webserver
  template:
    metadata:
      labels:
        app: win-webserver
      name: win-webserver
    spec:
     containers:
      - name: windowswebserver
        image: mcr.microsoft.com/windows/servercore:ltsc2019
     nodeSelector:
      kubernetes.io/os: windows

• The pod takes some time to become ready, exec into the pod kubectl exec -it POD_NAME -- cmd
• Create the following batch file:

echo @echo off > infinite_nslookup.bat
echo :loopStart >> infinite_nslookup.bat
echo   nslookup www.google.com >> infinite_nslookup.bat
echo goto loopStart >> infinite_nslookup.bat

• Execute the previously created file infinite_nslookup.bat
• It will take around a minute for DNS requests to start intermittently failing.

Other information (workarounds you have tried, documentation consulted, etc):

• Increasing the number of kube-dns pods did not help with mitigating of this issue.