Add KEP-4680 device health reporting with message field support

[harche]

Summary

Adds KEP-4680 device health reporting to the example driver. The driver implements the DRAResourceHealthServer gRPC interface (dra-health/v1alpha1), allowing kubelet to stream device health updates that appear in pod.status.containerStatuses[].allocatedResourcesStatus.

• Health monitoring is always enabled (Beta feature, default-on in K8s 1.36)
• A health simulator generates realistic scenarios (temperature warnings, ECC errors, communication failures, recovery cycles)
• Uses actual device names from the allocatable set (works with partitioned devices)

Verification

kubectl get pod -n health-reporting pod0 \
  -o jsonpath='{.status.containerStatuses[0].allocatedResourcesStatus}' | jq .

[
  {
    "name": "claim:gpu",
    "resources": [
      {
        "health": "Healthy",
        "message": "Device gpu-0 operating normally, temperature: 46°C",
        "resourceID": "k8s.gpu.example.com/gpu=common"
      }
    ]
  }
]

Cluster requirements

• Kubernetes 1.36+ (ResourceHealthStatus and ResourceHealthStatusMessage feature gates are Beta and enabled by default)

[k8s-ci-robot]

Welcome @harche!

It looks like this is your first PR to kubernetes-sigs/dra-example-driver 🎉. Please refer to our pull request process documentation to help your PR have a smooth ride to approval.

You will be prompted by a bot to use commands during the review process. Do not be afraid to follow the prompts! It is okay to experiment. Here is the bot commands documentation.

You can also check if kubernetes-sigs/dra-example-driver has its own contribution guidelines.

You may want to refer to our testing guide if you run into trouble with your tests not passing.

If you are having difficulty getting your pull request seen, please follow the recommended escalation practices. Also, for tips and tricks in the contribution process you may want to read the Kubernetes contributor cheat sheet. We want to make sure your contribution gets all the attention it needs!

Thank you, and welcome to Kubernetes. 😃

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: harche
Once this PR has been reviewed and has the lgtm label, please assign klueska for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[harche]

/hold for the implementation PRs to merge,

kubernetes/enhancements#4680 (comment)

[harche]

I will update once 1.36 beta is cut

[harche]

/cc @SergeyKanzhelev @nojnhuh

[harche]

I will update once 1.36 beta is cut

/hold cancel

[harche]

/cc @SergeyKanzhelev @nojnhuh

/hold I am adding a feature to trigger the health status update in this example driver.

[harche]

Putting this on hold until #201 merges. Both PRs modify the e2e test infrastructure (e2e_setup_test.go, e2e_test.go) and will conflict. Will rebase after #201 lands.

/hold

[pohly]

As mentioned before, I don't like that DRA drivers have to interact with the gRPC interface (drahealthv1alpha1 currently, despite the beta graduation of the feature?!). Can we first improve the kubeletplugin support for this feature (abstract from underlying gRPC interface similar to how it's done for the main DRA kubelet interace, better documentation) and only then make the DRA example driver use that improved support?