Honor stderrthreshold when logtostderr is enabled

[pierluigilenoci]

Summary

Opt into the new klog behavior so that -stderrthreshold is honored even when -logtostderr=true (the default). Set stderrthreshold=INFO to preserve backward compatibility.

Background

When -logtostderr=true, -stderrthreshold was ignored -- all logs went to stderr. Fixed in kubernetes/klog#432 (v2.140.0+), but projects must opt in.

Changes

• Added flag.Set("legacy_stderr_threshold_behavior", "false") and flag.Set("stderrthreshold", "INFO") after every klog.InitFlags() call (7 call sites)
• Bumped k8s.io/klog/v2 from v2.130.1 to v2.140.0
• Added missing "flag" import where needed

References

• stderrthreshold not honored when logtostderr is set kubernetes/klog#212
• feat: fix stderrthreshold not honored when logtostderr is set (#212) + two new flags kubernetes/klog#432

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[pierluigilenoci]

Hi @vmarmol, @dashpole, @rjnagal -- would you be willing to review? Thank you!

[pierluigilenoci]

@googlebot I signed it.

[pierluigilenoci]

@googlebot I signed it.

[pierluigilenoci]

Hi @vmarmol @dashpole @rjnagal — friendly follow-up. The CLA check is passing. This is a small change to opt into the fixed klog stderrthreshold behavior.

Would you be able to review when you get a chance? Thank you!

[dashpole]

I don't work on cAdvisor anymore.

[pierluigilenoci]

Thank you for letting me know, @dashpole! Could @vmarmol or @rjnagal point me to the right person to review this? I see @thaJeztah and @olyazavr have been active recently — would either of you be able to take a look? It's a small klog stderrthreshold fix. Thank you!