Error: HttpStatus: 422 : admission webhook "vtcanodepool.kb.io" denied the request: TcaNodePool.telco.vmware.com "[nodepool name]" is invalid: spec.network: Invalid value: "network": cannot be modified

Products

• VMware Telco Cloud Automation

Issue/Introduction

• When attempting to scale an existing nodepool via the TCA UI, the operation fails with an error code: CAS110305.
• Viewing the details of the error you see the message: 
  
  Failed to apply NodePool CR. Cluster: [CLUSTER_NAME], Operation: EditNodePool, Intent: ########-####-####-####-############, NodePool: [NODEPOOL_NAME], Details: HttpStatus: 422 : admission webhook "vtcanodepool.kb.io" denied the request: TcaNodePool.telco.vmware.com "[NODEPOOL_NAME]" is invalid: spec.network: Invalid value: "network": cannot be modified

• Viewing the network section of the tknp resource you see multiple nameservers on a single line as below:
  
  network:
  devices:
    - dhcp4: true
      nameservers:
        - 192.168.0.100, 192.168.0.101

Environment

2.2

Cause

Post-deployment, it is not supported to change the network configuration of a nodepool. In some scenarios, multiple nameservers may have been configured and in the K8s configuration they are stored as a comma-separated single line. Subsequent updates to the cluster may attempt to push the two nameservers each on their own line. While the data is not changed, K8s perceives this as a change and denies it.

Resolution

Temporary disabling of the validating webhooks can allow for an override to be pushed to the configuration. The steps required provide a potential for irrecoverable issues and support should be engaged for guidance.