unprefixed keys are not allowed

[ademariag]

What would you like to be added: The ability to add no namespace

Why is this needed:
I am using GKE, and in order to use the Nvidia GPU Operator correctly I need to disable the installation of the device plugin by adding this label

gke-no-default-nvidia-gpu-device-plugin=true

see https://cloud.google.com/kubernetes-engine/docs/how-to/gpu-operator#setup-node-pool

I am using

apiVersion: nfd.k8s-sigs.io/v1alpha1
kind: NodeFeatureRule
metadata:
  name: gke-gpu-labeler
spec:
  rules:
    - name: label-gke-gpu-nodes
      labels:
        gke-no-default-nvidia-gpu-device-plugin: "true"
      matchFeatures:
        - feature: pci.device
          matchExpressions:
            vendor:
              op: In
              value:
                - 10de

which unfortunately produces feature.node.kubernetes.io/gke-no-default-nvidia-gpu-device-plugin=true

Unfortunately NFD offers no ways that I can see to remove the prefix namespace.
I understand that it is against best practices, but we're all adults :)

[ademariag]

nevermind! https://kubernetes-sigs.github.io/node-feature-discovery/v0.15/reference/master-configuration-reference.html#autodefaultns

even with this flag disabled, I get

E0307 01:06:34.233420       1 nfd-master.go:642] "ignoring label" err="unprefixed keys are not allowed" labelKey="gke-no-default-nvidia-gpu-device-plugin"

[fmuyassarov]

/assign

[fmuyassarov]

I believe this is a bug rather than a feature since I expected DisableAutoPrefix to prevent the namespace from being added, but it currently does not. However, we can fix this, for example, within the filterFeatureLabels(). @marquiz any thoughts, are we okay to allow skipping namespace addition?

[fmuyassarov]

I've tested it and even when the DisableAutoPrefix feature gate is enabled, custom labels don't get set.

 args:
    - "-feature-gates=DisableAutoPrefix=true"

[marquiz]

I've tested it and even when the DisableAutoPrefix feature gate is enabled, custom labels don't get set.

Yes, this is by design, unprefixed labels are being blocked. I think we could allow those in case DisableAutoPrefix is enabled. Would kinda make sense.

[marquiz]

I think we should also consider graduating DisableAutoPrefix to beta with on-by-default. Otherwise we'll never get any feedback for that...

[fmuyassarov]

I've tested it and even when the DisableAutoPrefix feature gate is enabled, custom labels don't get set.

Yes, this is by design, unprefixed labels are being blocked. I think we could allow those in case DisableAutoPrefix is enabled. Would kinda make sense.

I will send a patch for review then.