fix: honor -stderrthreshold when -logtostderr is set#4903
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pierluigilenoci wants to merge 1 commit intocilium:mainfrom
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fix: honor -stderrthreshold when -logtostderr is set#4903pierluigilenoci wants to merge 1 commit intocilium:mainfrom
pierluigilenoci wants to merge 1 commit intocilium:mainfrom
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klog v2 defaults -logtostderr to true, which silently causes -stderrthreshold to be ignored. klog v2.140.0 introduced the legacy_stderr_threshold_behavior flag that restores the correct interaction between the two flags (see kubernetes/klog#432). This commit sets legacy_stderr_threshold_behavior=false after klog.InitFlags in pkg/logger/klog_bridge.go and sets stderrthreshold=INFO so the default behavior is preserved but users can now override it on the command line. Tetragon is already on klog v2.140.0 so no dependency bump is needed. Ref: kubernetes/klog#212 Signed-off-by: Pierluigi Lenoci <pierluigi.lenoci@gmail.com> Signed-off-by: Pierluigi Lenoci <pierluigilenoci@gmail.com>
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Hi! |
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Apologies — I missed that #4805 had already been submitted and closed. I mistakenly believed I hadn't opened a PR for this repository yet. Closing this as a duplicate. Sorry for the noise. |
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What this PR does
klog v2 defaults
-logtostderrtotrue, which silently causes-stderrthresholdto be ignored — all log messages of every severity are unconditionally written to stderr. There is no way for users to filter which severity levels reach stderr.This has been an open issue since 2020: kubernetes/klog#212.
klog v2.140.0 (kubernetes/klog#432) introduces a
legacy_stderr_threshold_behaviorflag that fixes this. This PR setslegacy_stderr_threshold_behavior=falseafterklog.InitFlagsinpkg/logger/klog_bridge.goand setsstderrthreshold=INFOso the default behavior is preserved but users can now override it on the command line (e.g.-stderrthreshold=WARNING).Tetragon is already on klog v2.140.0, so no dependency bump is needed.
Why it matters
While Tetragon's custom logging setup already routes klog output by severity via
SetOutputBySeverity, this change ensures the klog-internal stderrthreshold mechanism works correctly as a defense-in-depth measure. In production clusters, log aggregation systems (Fluentd, Fluent Bit, Loki, Datadog, etc.) benefit from proper severity filtering at the klog level.Changed files
pkg/logger/klog_bridge.golegacy_stderr_threshold_behavior=false+stderrthreshold=INFOafterklog.InitFlags