OCPBUGS-99652: prevent duplicate NOTRACK iptables rules on container restart

[ssonigra]

What does this PR do?

Prevents duplicate NOTRACK iptables rules from being added to the raw table on every ovnkube-controller container restart by checking if each rule already exists before appending it.

Why is this important?

Without this fix, every ovnkube-controller restart blindly appends duplicate rules for the Geneve and hybrid overlay VXLAN ports. Because NOTRACK is a non-terminating target, all duplicates are evaluated sequentially, inflating packet counters and wasting CPU cycles.

Implementation

The fix adds an ensure-notrack-rule helper function that:

• Checks if the rule already exists
• Adds it if missing
• Removes duplicates if present
• Does nothing if exactly one rule exists

Note: On master / OCP 5.x, this bug was already resolved as a side effect of the nftables migration (PR #3038), which uses nft flush table before re-adding rules. This fix targets the release-4.x branches that still use iptables.

Jira

https://redhat.atlassian.net/browse/OCPBUGS-99652

Related PRs

• OCPBUGS-99652: prevent duplicate NOTRACK iptables rules on container restart #3093 (same fix for release-4.23)

Test plan

• make build passes
• make test-unit passes
• Manual: restart ovnkube-node pod multiple times, verify iptables -t raw -L PREROUTING -n -v --line-numbers shows no duplicate NOTRACK rules

🤖 Generated with Claude Code

[openshift-merge-bot]

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[openshift-ci-robot]

@ssonigra: This pull request references Jira Issue OCPBUGS-99652, which is invalid:

• expected the bug to target the "4.22.0" version, but no target version was set
• expected the bug to be in one of the following states: NEW, ASSIGNED, POST, but it is ON_QA instead
• release note text must be set and not match the template OR release note type must be set to "Release Note Not Required". For more information you can reference the OpenShift Bug Process.
• expected Jira Issue OCPBUGS-99652 to depend on a bug targeting a version in 5.0.0 and in one of the following states: MODIFIED, ON_QA, VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA), but no dependents were found

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

What does this PR do?

Prevents duplicate NOTRACK iptables rules from being added to the raw table on every ovnkube-controller container restart by checking if each rule already exists before appending it.

Why is this important?

Without this fix, every ovnkube-controller restart blindly appends duplicate rules for the Geneve and hybrid overlay VXLAN ports. Because NOTRACK is a non-terminating target, all duplicates are evaluated sequentially, inflating packet counters and wasting CPU cycles.

Implementation

The fix adds an ensure-notrack-rule helper function that:

• Checks if the rule already exists
• Adds it if missing
• Removes duplicates if present
• Does nothing if exactly one rule exists

Note: On master / OCP 5.x, this bug was already resolved as a side effect of the nftables migration (PR #3038), which uses nft flush table before re-adding rules. This fix targets the release-4.x branches that still use iptables.

Jira

https://redhat.atlassian.net/browse/OCPBUGS-99652

Related PRs

• OCPBUGS-99652: prevent duplicate NOTRACK iptables rules on container restart #3093 (same fix for release-4.23)

Test plan

• make build passes
• make test-unit passes
• Manual: restart ovnkube-node pod multiple times, verify iptables -t raw -L PREROUTING -n -v --line-numbers shows no duplicate NOTRACK rules

🤖 Generated with Claude Code

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

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[openshift-ci]

@ssonigra: 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-metal-ipi-ovn-secondary-encap	eb172cc	link	false	/test e2e-metal-ipi-ovn-secondary-encap
ci/prow/security	eb172cc	link	false	/test security

Full PR test history. Your PR dashboard.

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