Allow node-role labeling

[paulbsch]

Why do you want this feature?
In our use case, we utilize node-role.kuberneties.io/{role-name} labels. It is also useful for identifying nodes in the cluster when using tools like kubectl. Example:

$ kubectl get nodes
NAME                                           STATUS    ROLES             AGE       VERSION
ip-192-168-66-184.us-west-2.compute.internal   Ready     jarvice-compute   37m       v1.11.5
ip-192-168-71-24.us-west-2.compute.internal    Ready     jarvice-compute   37m       v1.11.5
ip-192-168-75-4.us-west-2.compute.internal     Ready     jarvice-system    37m       v1.11.5

Currently, eksctl doesn't allow any label matching the kubernetes.io domain. This makes perfect sense with respect to labels that should be immutable ("kubernetes.io/arch", kubernetes.io/hostname", etc.) However, node role labels don't seem to fall into that category.

What feature/behavior/change do you want?
Please alllow node role labeling. i.e. node-role.kubernetes.io/{role-name} e.g. node-role.kubernetes.io/compute

[errordeveloper]

Do we currently return unknown 'kubernetes.io' or 'k8s.io' labels were specified kind of error?

It should be fairly easy to add node-role.kubernetes.io, would you like to try adding it yourself?

I believe it just needs to be added to the list of domain prefixes here:

https://github.com/weaveworks/eksctl/blob/2319fa8dd39c755bc2e296dff3bc36595da0b560/pkg/apis/eksctl.io/v1alpha4/validation.go#L68-L72

[paulbsch]

It does return that error, yes.

Adding that domain prefix solves the issue. I will submit a pull request.

[errordeveloper]

Closed via #582.