fix: honor klog -stderrthreshold even when -logtostderr is true#18231
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klog v2 defaults -logtostderr to true, which silently ignores -stderrthreshold — all log levels go to stderr unconditionally. This has been an open issue since 2020 (kubernetes/klog#212). klog v2.140.0 introduced a fix behind an opt-in flag (legacy_stderr_threshold_behavior). This commit enables the fix across all klog.InitFlags call sites so that -stderrthreshold is honored, while preserving the current default behavior (stderrthreshold=INFO means all logs still go to stderr unless the user overrides it on the command line). Ref: kubernetes/klog#212 Ref: kubernetes/klog#432 Signed-off-by: Pierluigi Lenoci <pierluigi.lenoci@gmail.com>
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Summary
klog v2 defaults
-logtostderrtotrue, which silently ignores any-stderrthresholdvalue the user sets — all log levels are sent to stderrunconditionally. This has been a known issue since 2020
(kubernetes/klog#212).
klog v2.140.0 (already the version in kops
go.mod) introduced thelegacy_stderr_threshold_behaviorflag that, when set tofalse, makes-stderrthresholdwork as documented even when-logtostderristrue(kubernetes/klog#432).
This PR opts into the fix across all 9
klog.InitFlagscall sites (onewas already patched in
cmd/kops/root.go; this commit normalizes the commentand adds the same two
Setcalls to the remaining 8 sites):channels/cmd/channels/main.goflag(default)cmd/kops/root.gogoflag(alias forflag)cmd/kops-controller/main.goflag(default)cmd/kube-apiserver-healthcheck/main.goflag(default)cmd/nodeup/main.goflag(default)dns-controller/cmd/dns-controller/main.goflag(default)protokube/cmd/protokube/main.goflag(default)tools/otel/traceserver/main.goflag(default)upup/tools/generators/fitask/main.goflag(default)tests/e2e/kubetest2-kops/deployer/deployer.goklogFlags(custom)The default
stderrthreshold=INFOpreserves current behavior — all logsstill go to stderr by default. The difference is that users can now
meaningfully set
-stderrthreshold=WARNING(or higher) to filter outlower-severity messages.
What changed
After each
klog.InitFlags(...)call, two flag-set operations are added:No dependency changes — kops already uses klog v2.140.0.
References