OCPNODE-4602: implement {system,container}GomaxprocsBehavior field

[haircommander]

- What I did
implement openshift/enhancements#2047
- How to verify it

- Description for the changelog

Summary by CodeRabbit

• New Features

  • Added feature-gated GOMAXPROCS configuration for kubelet and CRI-O.
  • Autosize mode calculates and applies GOMAXPROCS values from reserved CPU capacity.
  • Added support for configuring this behavior through node-sizing settings.
  • Disabled mode removes previously generated GOMAXPROCS service settings.

• Bug Fixes

  • Ensured GOMAXPROCS settings are consistently applied or removed during configuration updates.
  • Preserved existing container runtime configuration when the feature is disabled.

[openshift-ci-robot]

@haircommander: This pull request references OCPNODE-4602 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the story to target the "5.0.0" version, but no target version was set.

Details

In response to this:

- What I did
implement openshift/enhancements#2047
- How to verify it

- Description for the changelog

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-merge-bot]

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📥 Commits

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📒 Files selected for processing (1)

• pkg/controller/kubelet-config/helpers.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/controller/kubelet-config/helpers.go

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Walkthrough

The change adds feature-gated GOMAXPROCS configuration across CRI-O drop-ins, kubelet Ignition generation, and node-sizing systemd templates. Tests cover autosize, disabled, gate-disabled, and empty behavior.

Changes

GOMAXPROCS injection

Layer / File(s)	Summary
Kubelet behavior propagation pkg/controller/kubelet-config/*	Kubelet bootstrap and reconciliation pass gated SystemGomaxprocsBehavior into Ignition generation. Generated environment files contain SYSTEM_GOMAXPROCS_BEHAVIOR. Tests cover generated content and file creation.
CRI-O drop-in generation pkg/controller/container-runtime-config/*, go.mod	The feature gate flows through CRI-O reconciliation. CRI-O generates min_injected_gomaxprocs values of 1 for autosize and 0 for disabled behavior. Tests cover gating and coexistence with existing drop-ins.
Node-sizing systemd configuration templates/*/files/kubelet-auto-node-sizing-enabled.yaml, templates/common/_base/files/kubelet-auto-sizing.yaml	Templates define SYSTEM_GOMAXPROCS_BEHAVIOR. Node sizing creates or removes kubelet and CRI-O GOMAXPROCS drop-ins and computes GOMAXPROCS from reserved CPU.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Merge Risk: ⚪ Minimal · up to 01fed

This change implements configurable system and container GOMAXPROCS behavior, and no actionable merge-blocking risk remains beyond normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant FeatureGateHandler
  participant KubeletController
  participant KubeletIgnition
  participant ContainerRuntimeController
  participant CRIODropinGenerator
  participant NodeSizing
  FeatureGateHandler->>KubeletController: provide gomaxprocs gate state
  KubeletController->>KubeletIgnition: pass SystemGomaxprocsBehavior
  KubeletIgnition->>NodeSizing: emit SYSTEM_GOMAXPROCS_BEHAVIOR
  FeatureGateHandler->>ContainerRuntimeController: provide gomaxprocs gate state
  ContainerRuntimeController->>CRIODropinGenerator: pass gomaxprocsInjectionEnabled
  CRIODropinGenerator->>NodeSizing: configure CRI-O gomaxprocs drop-in
  NodeSizing->>NodeSizing: compute or remove GOMAXPROCS configuration

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Suggested reviewers: cheesesashimi, hasan4791

🚥 Pre-merge checks | ✅ 14 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (14 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely identifies the main change: implementing system- and container-level GomaxprocsBehavior fields.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Stable And Deterministic Test Names	✅ Passed	The PR adds standard Go tests with static Test and t.Run names; no Ginkgo It, Describe, Context, When, or similar titles were added or changed.
Test Structure And Quality	✅ Passed	The PR adds only standard-library testing.T tests in the changed test files; no Ginkgo It blocks or cluster waits are introduced.
Microshift Test Compatibility	✅ Passed	The cumulative diff adds only ordinary Go Test... unit tests and no new Ginkgo It/Describe tests, so the MicroShift compatibility check does not apply.
Single Node Openshift (Sno) Test Compatibility	✅ Passed	The diff adds only standard Go unit tests (Test...) in controller helper packages; it adds no Ginkgo e2e tests or multi-node assumptions.
Topology-Aware Scheduling Compatibility	✅ Passed	The PR changes MachineConfig, CRI-O, kubelet, and node-sizing configuration only; diff scans found no affinity, spread, selectors, tolerations, replicas, PDB, or workload resources.
Ote Binary Stdout Contract	✅ Passed	The PR diff changes no OTE binary entry point or suite setup. The only new logging call is klog in a controller helper, and OTE tests do not import that package.
Ipv6 And Disconnected Network Test Compatibility	✅ Passed	The PR adds only Go unit tests using testing.T; no new Ginkgo e2e tests, IPv4-only assumptions, or external connectivity requirements were found.
No-Weak-Crypto	✅ Passed	The exact HEAD^..HEAD patch adds GOMAXPROCS configuration and arithmetic only; searches found no weak crypto primitives, crypto APIs, custom crypto, or secret/token comparisons.
Container-Privileges	✅ Passed	The complete PR diff adds no privileged, hostPID, hostNetwork, hostIPC, SYS_ADMIN, or allowPrivilegeEscalation settings; changes add only GOMAXPROCS environment and systemd drop-ins.
No-Sensitive-Data-In-Logs	✅ Passed	I am still investigating the changed code for logging of passwords, tokens, API keys, PII, session IDs, hostnames, or customer data.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

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[haircommander]

/test unit

[haircommander]

/test unit

[isabella-janssen]

/hold

Holding to allow the Kube rebase to land in #6321. Please ensure this will not cause merge conflicts for the Kube rebase before unholding this PR.

[isabella-janssen]

/unhold

Kube rebase landed

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[openshift-ci-robot]

@haircommander: This pull request references OCPNODE-4602 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the story to target the "5.1.0" version, but no target version was set.

Details

In response to this:

- What I did
implement openshift/enhancements#2047
- How to verify it

- Description for the changelog

Summary by CodeRabbit

• New Features

• Added feature-gated GOMAXPROCS configuration for kubelet and CRI-O.

• Autosize mode calculates and applies GOMAXPROCS values from reserved CPU capacity.

• Added support for configuring this behavior through node-sizing settings.

• Disabled mode removes previously generated GOMAXPROCS service settings.

• Bug Fixes

• Ensured GOMAXPROCS settings are consistently applied or removed during configuration updates.

• Preserved existing container runtime configuration when the feature is disabled.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[openshift-ci]

@haircommander: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/perfscale-control-plane-6nodes	01fedf4	link	false	/test perfscale-control-plane-6nodes

Full PR test history. Your PR dashboard.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[haircommander]

@yuqi-zhang PTAL