feat(collector): use FlowSummary to reduce conntrack peak memory#30
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Introduce a lightweight FlowSummary struct that holds only the fields kubenetmon actually uses (tuples and counters) from conntrack.Flow. After each conntrack dump the full []conntrack.Flow is immediately converted to []FlowSummary and released, allowing the GC to reclaim the heavier Flow objects (which carry unused fields like Status, Timeout, ProtoInfo, Labels, SeqAdj, SynProxy, etc.) before the send loop begins. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The `rawFlows = nil` assignment was flagged by golangci-lint (ineffassign) since the variable is not read after that point. The local variable becomes unreachable after toFlowSummaries returns, allowing the GC to collect it without the explicit nil assignment. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
andreev-io
requested changes
Mar 20, 2026
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| now := collector.clock.Now() | ||
| flows, err := collector.conntrack.Dump(&conntrack.DumpOptions{ZeroCounters: true}) | ||
| rawFlows, err := collector.conntrack.Dump(&conntrack.DumpOptions{ZeroCounters: true}) |
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Thank you for putting this up. I think we should swap in conntrack for a fork like we do internally and replace the Flow struct at that level during conversion from netlink messages. Otherwise this change may do more harm than good, since it will be allocating 3 times for each flow.
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updated to depend on ClickHouse forked conntrack
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
andreev-io
approved these changes
Mar 23, 2026
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Summary
github.com/ti-mo/conntrackto the ClickHouse fork (github.com/ClickHouse/conntrack) which provides a nativeFlowSummarystruct andDumpFlowSummaryFilterAPI.DumpFlowSummaryFilterto dump only the fields kubenetmon needs (tuples and counters) directly from the kernel, avoiding allocation of the heavierconntrack.Flowstruct with its unused fields (Status,Timeout,ProtoInfo,Labels,SeqAdj,SynProxy, etc.).shouldIgnoreFlowand all related code to operate onconntrack.FlowSummaryinstead ofconntrack.Flow.Mirrors ClickHouse/data-plane-application#31052 for the OSS codebase.
Test plan
TestShouldIgnoreFlowsub-tests to useFlowSummaryTestCollectintegration test passes (exercises the full dump → convert → send path)go test ./...)🤖 Generated with Claude Code