AKS Not able to upgrade default node pool

Question

Hello,

We provision our AKS clusters using Terraform, as per Terraform expectation we have used System Pool as the default node pool from the pipeline

Problem here is while trying to upgrade AKS it could able to upgrade control plane and default node pool errors out with
performing CreateOrUpdate: agentpools.AgentPoolsClient#CreateOrUpdate: Failure sending request: StatusCode=0 -- Original Error: Code="CustomKubeletConfigOrCustomLinuxOSConfigCanNotBeChanged" Message="CustomKubeletConfig or CustomLinuxOSConfig can not be changed for this operation

From Azure console activity log

"status": {

        "value": "Failed",
        "localizedValue": "Failed"
    },
    "subStatus": {
        "value": "BadRequest",
        "localizedValue": "Bad Request (HTTP Status Code: 400)"

Any hints to fix this

Answer 1

Hi @K.R.S Bhuvanesh

Thanks for reaching Microsoft Q&A

Regarding this error "CustomKubeletConfigOrCustomLinuxOSConfigCanNotBeChanged" you might be missing the config file with the allowed parameters. Anything different will not allow you to perform any change. On this case you should check your terraform template. It only works during the creation of the cluster or nodepool.

https://learn.microsoft.com/en-us/azure/aks/custom-node-configuration?tabs=linux-node-pools#kubelet-custom-configuration

Hope this helps. Please "Accept as Answer" if it helped, so that it can help others in the community looking for help on similar topics.