Issue¶

Unable to connect to the server: dial tcp: lookup : no such host¶

The Private Cluster option is enabled while creating the AKS cluster.

az aks show -n <aks-name> -g <resource-group-name> | grep private

Category: ClientError; Code: UpgradeFailed; SubCode: DrainDidNotComplete¶

https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/error-code-poddrainfailure

Reason: If the Allowed Disruption value is 0, the node drain will fail during the upgrade process.

Solution: Note that all the solution will not work if the app has been deployed via argocd helm charts.

• Enable pods to drain

  kubectl edit pdb <pdb-name> -n <pdb-namespace> #then change allowedDisruptions
  

• Back up, delete, and redeploy the PDB

  kubectl get pdb <pdb-name> -n <pdb-namespace> -o yaml > pdb_backup.yaml
  kubectl delete pdb <pdb-name> -n <pdb-namespace>
  kubectl apply -f pdb_backup.yaml
  

• Delete the pods that can't be drained