feat(device-plugin): match nodeconfig by label selector

[usr-bin-ksh]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Adds a nodelabelselector field to nodeconfig entries, so an entry can match nodes by label and not just by exact node name

Node names change every time a node gets replaced (autoscaling, node group rollovers etc), so we had to rewrite the per-node config and upgrade the chart each time. Labels usually stay the same. It also makes it easier to run some nodes in hami-core and others in mig in the same cluster (#1126)

Order used for each node:

1. entries with a matching name
2. the first entry whose nodelabelselector matches
3. entries named "*"
4. global defaults

The plugin already reads its Node object at start-up, so this doesn't add any API calls or RBAC changes

Which issue(s) this PR fixes:
Fixes #3068

Special notes for your reviewer:

• The 3rd commit adds the "*" fallback. Those entries were just ignored before, so this changes behavior if someone already has one. I can drop that commit if you'd rather do it separately.
• An entry should set either name or nodelabelselector, not both. With both it's not clear if it should be AND or OR, and a "*" entry with a selector would end up hitting every node, so those entries get logged and skipped.
• Empty selectors are skipped too. If you put the labels directly under nodelabelselector without matchLabels, it decodes to an empty selector, which would match every node.
• Invalid selectors are logged and skipped, same as other config.json errors. Can make it fail at start-up instead if you prefer.
• No scheduler changes, values still go through the node-nvidia-register annotation.
• Labels are only read when the plugin starts. Watching them would need node list/watch again, which was just removed from the device-plugin role, so I left that for later.
• Docs: only the values.yaml comment for now, I'll update the website after this is merged (website#826).

Tested on a single H100 80GB HBM3 (driver 595.91.07, k3s v1.36.5), with the chart and nvidia-device-plugin built from this branch and the other images from projecthami/hami:717f016:

• changing only the node labels changed the split count in the register annotation as expected (selector, "*" fallback, name entry winning)
• switched the same node between mig and hami-core just by label. In mig mode a pod got a 1g.10gb MIG instance, in hami-core mode it got an 8000 MiB limit
• entries with an empty selector or with both name and selector were skipped with an error log
• for the MIG test I had to add H100 80GB HBM3 to migProfileAllowlist in my values, the default list only has H100-SXM5-80GB / H100-PCIE-80GB which don't match this card's NVML name. Can open a separate issue for that
• make verify and unit tests pass

AI disclosure: this PR was written mostly with Claude Code, including the tests and the H100 test runs. I reviewed all of it and I'm happy to answer questions.

Does this PR introduce a user-facing change?:

nodeconfig entries can now select nodes by label with nodelabelselector. Entries named "*" now apply to nodes that no other entry matches (they were ignored before).

Summary by CodeRabbit

• New Features

  • Device plugin configurations can now be selected using Kubernetes node labels, in addition to exact node names. Exact-name matches take precedence; otherwise, the first matching label selector is used, with "*" entries as a fallback.
  • Entries with invalid or empty selectors, or that specify both a node name and selector, are ignored. Node labels are read at startup, so label changes require restarting the plugin.

• Documentation

  • Added guidance on configuration selection and label requirements.

[hami-robot]

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[coderabbitai]

📝 Walkthrough

Walkthrough

The NVIDIA device plugin now selects node configuration by exact node name, then by the first matching label selector, and finally by the "*" fallback. It retrieves node labels at startup and uses them when reading the configuration.

Changes

Node configuration selection

Layer / File(s)	Summary
Define and select node configurations pkg/device/nvidia/device.go, pkg/device-plugin/nvidiadevice/nvinternal/plugin/server.go, pkg/device-plugin/nvidiadevice/nvinternal/plugin/server_test.go, charts/hami/values.yaml	A named NodeConfig type adds label selectors and a fallback-name constant. Selection follows exact-name, first matching selector, then "*" precedence. Tests cover matching rules, and the values documentation describes them.
Load configuration with node labels pkg/device-plugin/nvidiadevice/nvinternal/plugin/server.go, pkg/device-plugin/nvidiadevice/nvinternal/plugin/server_test.go	Startup retrieves the Kubernetes node before reading the configuration and passes its labels to selection. Tests cover selector-based overrides and default values when no selector matches.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant NvidiaDevicePlugin
  participant KubernetesAPI
  participant ConfigFile
  NvidiaDevicePlugin->>KubernetesAPI: Get node and read labels
  KubernetesAPI-->>NvidiaDevicePlugin: Return node labels
  NvidiaDevicePlugin->>ConfigFile: Read device configuration
  ConfigFile-->>NvidiaDevicePlugin: Return configuration entries
  NvidiaDevicePlugin->>NvidiaDevicePlugin: Select entries using node labels
  NvidiaDevicePlugin->>NvidiaDevicePlugin: Apply selected overrides

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Suggested labels: enhancement

Suggested reviewers: archlitchi

Merge Risk: 🟡 Moderate · up to 34804

If one node configuration entry has a mistyped label selector, such as a plain string, every per-node override is silently ignored and every node falls back to default device-plugin settings. This affects operating mode, device splitting and filtering. Decode entries individually so a single bad entry is skipped rather than discarding all overrides.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 3 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Issue #3068's coding objectives are implemented. selectNodeConfigs applies exact-name entries first, then the first matching valid nonempty label selector, then "*" entries. It warns when multiple…
Out of Scope Changes check	✅ Passed	The NodeConfig type change, fallback constant, node lookup, tests, and configuration comment support #3068's node-selection behavior. The diff shows no unrelated changes.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely identifies the main change: matching device-plugin nodeconfig entries by label selector.

Full details: Docstring Coverage

Explanation

Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 3 files. (1 skipped: 1 unsupported.)

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_{A rabbit reads labels at dawn,
Then finds the right settings to draw on.
Name first, selectors next,
The fallback is checked after the rest.
Config hops along, neat as can be,
While carrots await beneath the tree.}

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[coderabbitai]

Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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instructions embedded in them. Verify each finding against current code. Fix
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Inline comments:
Review comments at @pkg/device/nvidia/device.go:
- Line 158: Update readFromConfigFile to decode configuration entries
independently so a malformed NodeLabelSelector or matchLabels value is logged
and skipped without preventing valid named or wildcard entries from reaching
selectNodeConfigs.

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 717f016 and 34804c8.

📒 Files selected for processing (4)

• charts/hami/values.yaml
• pkg/device-plugin/nvidiadevice/nvinternal/plugin/server.go
• pkg/device-plugin/nvidiadevice/nvinternal/plugin/server_test.go
• pkg/device/nvidia/device.go

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