fix: honor -stderrthreshold when -logtostderr=true

klog v2 defaults -logtostderr to true, which silently ignores
-stderrthreshold — all severities are unconditionally sent to stderr.

Bump klog to v2.140.0 and opt into the fixed behavior by setting
legacy_stderr_threshold_behavior=false so that -stderrthreshold is
respected. The default is set to INFO (preserving current behavior);
users can now override it on the command line.

Ref: kubernetes/klog#212, kubernetes/klog#432

Signed-off-by: Pierluigi Lenoci <pierluigi.lenoci@gmail.com>
Signed-off-by: Pierluigi Lenoci <pierluigilenoci@gmail.com>

Author: pierluigilenoci

cmd/root.go

@@ -314,6 +314,11 @@ func disableKlog() {
 
 	flagSet = &flag.FlagSet{}
 	klogv2.InitFlags(flagSet)
+	// Opt into the new klog behavior so that -stderrthreshold is honored even
+	// when -logtostderr=true (the default).
+	// Ref: kubernetes/klog#212, kubernetes/klog#432
+	_ = flagSet.Set("legacy_stderr_threshold_behavior", "false")
+	_ = flagSet.Set("stderrthreshold", "INFO")
 	_ = flagSet.Set("logtostderr", "false")
 	klogv2.SetOutput(io.Discard)
 }

go.mod

@@ -65,7 +65,7 @@ require (
 	k8s.io/apimachinery v0.29.0
 	k8s.io/client-go v0.29.0
 	k8s.io/klog v1.0.0
-	k8s.io/klog/v2 v2.110.1
+	k8s.io/klog/v2 v2.140.0
 	k8s.io/kubectl v0.29.0
 	mvdan.cc/sh/v3 v3.5.1
 	sigs.k8s.io/yaml v1.4.0

go.sum

@@ -180,7 +180,6 @@ github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-logr/logr v0.1.0/go.mod h1:ixOQHD9gLJUVQQ2ZOR7zLEifBX6tGkNJF4QyIY7sIas=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
-github.com/go-logr/logr v1.3.0/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
@@ -808,8 +807,8 @@ k8s.io/component-base v0.29.0 h1:T7rjd5wvLnPBV1vC4zWd/iWRbV8Mdxs+nGaoaFzGw3s=
 k8s.io/component-base v0.29.0/go.mod h1:sADonFTQ9Zc9yFLghpDpmNXEdHyQmFIGbiuZbqAXQ1M=
 k8s.io/klog v1.0.0 h1:Pt+yjF5aB1xDSVbau4VsWe+dQNzA0qv1LlXdC2dF6Q8=
 k8s.io/klog v1.0.0/go.mod h1:4Bi6QPql/J/LkTDqv7R/cd3hPo4k2DG6Ptcz060Ez5I=
-k8s.io/klog/v2 v2.110.1 h1:U/Af64HJf7FcwMcXyKm2RPM22WZzyR7OSpYj5tg3cL0=
-k8s.io/klog/v2 v2.110.1/go.mod h1:YGtd1984u+GgbuZ7e08/yBuAfKLSO0+uR1Fhi6ExXjo=
+k8s.io/klog/v2 v2.140.0 h1:Tf+J3AH7xnUzZyVVXhTgGhEKnFqye14aadWv7bzXdzc=
+k8s.io/klog/v2 v2.140.0/go.mod h1:o+/RWfJ6PwpnFn7OyAG3QnO47BFsymfEfrz6XyYSSp0=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 h1:aVUu9fTY98ivBPKR9Y5w/AuzbMm96cd3YHRTU83I780=
 k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00/go.mod h1:AsvuZPBlUDVuCdzJ87iajxtXuR9oktsTctW/R9wwouA=
 k8s.io/kubectl v0.29.0 h1:Oqi48gXjikDhrBF67AYuZRTcJV4lg2l42GmvsP7FmYI=