mnp: Set hostname using downward API

[zeeke]

MultusNetworkPolicy implementation default to util.GetHostname to know the name of the node it is running on and filter pods accordingly. In some cases, that information might be not accurate, leading to a wrong behavior of the controller.

Use downward api to populate the --hostname argument of the multus network policy controller.

Link: https://github.com/kubernetes/component-helpers/blob/v0.34.2/node/util/hostname.go#L28

[coderabbitai]

Walkthrough

The multus-networkpolicy DaemonSet container now receives the node name at runtime: an environment variable K8S_NODE_NAME is set from spec.nodeName via a fieldRef, and the container args include a --hostname-override=$(K8S_NODE_NAME) flag to pass that per-node value to the process.

Changes

Cohort / File(s)	Summary
Kubernetes manifest configuration bindata/network/multus-networkpolicy/multus-networkpolicy.yaml	Adds environment variable K8S_NODE_NAME sourced from spec.nodeName via fieldRef and updates container args to include --hostname-override=$(K8S_NODE_NAME) for per-node hostname injection.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Verify the fieldRef path spec.nodeName is correct for the target Kubernetes API version.
• Confirm the --hostname-override=$(K8S_NODE_NAME) substitution syntax matches the container entrypoint/argument parsing expectations.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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• bindata/network/multus-networkpolicy/multus-networkpolicy.yaml (1 hunks)

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• bindata/network/multus-networkpolicy/multus-networkpolicy.yaml

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[openshift-ci]

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

Cache: Disabled due to data retention organization setting

Knowledge base: Disabled due to Reviews -> Disable Knowledge Base setting

📥 Commits

Reviewing files that changed from the base of the PR and between fda7a9f and c54a54b.

📒 Files selected for processing (1)

• bindata/network/multus-networkpolicy/multus-networkpolicy.yaml (1 hunks)

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-Focus on major issues impacting performance, readability, maintainability and security. Avoid nitpicks and avoid verbosity.

Files:

• bindata/network/multus-networkpolicy/multus-networkpolicy.yaml

[zeeke]

/retest

[zeeke]

/retest

[zeeke]

/retest

[zeeke]

@pliurh @LionelJouin @bpickard22 please, take a look when you have time.

[openshift-ci]

@zeeke: The following tests 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/e2e-aws-ovn-windows	a4d1b97	link	true	/test e2e-aws-ovn-windows
ci/prow/security	a4d1b97	link	false	/test security

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