silence the 'log.SetLogger(...) was never called' error

Signed-off-by: chaosi-zju <[email protected]>

Author: chaosi-zju

cmd/agent/main.go

@@ -21,6 +21,7 @@ import (
 
 	"k8s.io/component-base/cli"
 	_ "k8s.io/component-base/logs/json/register" // for JSON log format registration
+	"k8s.io/klog/v2"
 	controllerruntime "sigs.k8s.io/controller-runtime"
 	_ "sigs.k8s.io/controller-runtime/pkg/metrics"
 
@@ -29,6 +30,12 @@ import (
 
 func main() {
 	ctx := controllerruntime.SetupSignalHandler()
+	// Starting from version 0.15.0, controller-runtime expects its consumers to set a logger through log.SetLogger.
+	// If SetLogger is not called within the first 30 seconds of a binaries lifetime, it will get
+	// set to a NullLogSink and report an error. Here's to silence the "log.SetLogger(...) was never called; logs will not be displayed" error
+	// by setting a logger through log.SetLogger.
+	// More info refer to: https://github.com/karmada-io/karmada/pull/4885.
+	controllerruntime.SetLogger(klog.Background())
 	cmd := app.NewAgentCommand(ctx)
 	code := cli.Run(cmd)
 	os.Exit(code)

operator/cmd/operator/operator.go

@@ -21,6 +21,7 @@ import (
 
 	"k8s.io/component-base/cli"
 	_ "k8s.io/component-base/logs/json/register" // for JSON log format registration
+	"k8s.io/klog/v2"
 	controllerruntime "sigs.k8s.io/controller-runtime"
 	_ "sigs.k8s.io/controller-runtime/pkg/metrics"
 
@@ -29,6 +30,12 @@ import (
 
 func main() {
 	ctx := controllerruntime.SetupSignalHandler()
+	// Starting from version 0.15.0, controller-runtime expects its consumers to set a logger through log.SetLogger.
+	// If SetLogger is not called within the first 30 seconds of a binaries lifetime, it will get
+	// set to a NullLogSink and report an error. Here's to silence the "log.SetLogger(...) was never called; logs will not be displayed" error
+	// by setting a logger through log.SetLogger.
+	// More info refer to: https://github.com/karmada-io/karmada/pull/4885.
+	controllerruntime.SetLogger(klog.Background())
 	command := app.NewOperatorCommand(ctx)
 	code := cli.Run(command)
 	os.Exit(code)