If you ever encounter the following error, I’ll show you one way that helped me resolve my AKS cluster.

The cluster is in a failed state. If you didn't do an operation, AKS may resolve the provisioning status automatically if your cluster applications continue to run.

To further troubleshoot, you can refer to https://github.com/MicrosoftDocs/SupportArticles-docs/blob/main/support/azure/azure-kubernetes/cluster-node-virtual-machine-failed-state.md

For some background, I came to error through a faulty AKS cluster upgrade. Certain pods wouldn’t evict in a node. I created a new node pool with updated version to reschedule those pods to the new node pool. But I still get eviction issues due to configuration of the Pod Disruption Budget for certain pods.

I tried the alternate solution to manually restore the cluster by running in my terminal.

az resource update --name <aksName> --namespace Microsoft.ContainerService --resource-group <rgName> --resource-type ManagedClusters

Then you will see the status as Updating

Eventually the cluster status will be Succeeded (Running)

Hope this helps, but consider it a last resort and isn’t graceful. I would caution this approach in a production environment and plan accordingly.