cloudNAT settings can't be changed

[champoeva]

What happened: I tried changing the cloudNAT setting in one of my teams cluster's shoot, as it is described here https://github.com/gardener/gardener-extension-provider-gcp/blob/master/docs/usage-as-end-user.md. When I tried to 'Save' my changes the following error appeared "admission webhook "validation.gcp.provider.extensions.gardener.cloud" denied the request: spec.provider.infrastructureConfig.networks: Invalid value: gcp.NetworkConfig{VPC:(gcp.VPC)(nil), CloudNAT:(gcp.CloudNAT)(0xc000499b20), Internal:(string)(nil), Worker:"10.250.0.0/19", Workers:"", FlowLogs:(gcp.FlowLogs)(nil)}: field is immutable"

What you expected to happen: I expect the modification of the cloudNAT settings to be allowed.

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Gardener version (if relevant):
• Extension version: 1.5.1
• Kubernetes version (use kubectl version): 1.16.8
• Cloud provider or hardware configuration:
• Others:

[rfranzke]

cc @zanetworker

[zanetworker]

@champoeva which values were you trying to change?

[champoeva]

I was trying to put this: cloudNAT: minPortsPerVM: 2048 natIPNames:

• name: xf-factory-cloud-router-external-ip

under 'networks'