add --logging-format flag to kubelet

pkg/kubelet/apis/config/helpers_test.go

@@ -195,6 +195,7 @@ var (
 		"KubeReservedCgroup",
 		"KubeReserved[*]",
 		"KubeletCgroups",
+		"LogFormat",
 		"MakeIPTablesUtilChains",
 		"RotateCertificates",
 		"ServerTLSBootstrap",

pkg/kubelet/apis/config/types.go

@@ -357,6 +357,10 @@ type KubeletConfiguration struct {
 	// The purpose of this format is make sure you have the opportunity to notice if the next release hides additional metrics,
 	// rather than being surprised when they are permanently removed in the release after that.
 	ShowHiddenMetricsForVersion string
+	// LogFormat Flag specifies the structure of log messages.
+	// default value of logFormat is `text`
+	// Refer [Logs Options](https://github.com/kubernetes/component-base/blob/master/logs/options.go) for more information.
+	LogFormat string
 }
 
 // KubeletAuthorizationMode denotes the authorization mode for the kubelet

pkg/kubelet/apis/config/v1beta1/zz_generated.conversion.go

@@ -342,6 +342,7 @@ func autoConvert_v1beta1_KubeletConfiguration_To_config_KubeletConfiguration(in
 	out.VolumePluginDir = in.VolumePluginDir
 	out.ProviderID = in.ProviderID
 	out.KernelMemcgNotification = in.KernelMemcgNotification
+	out.LogFormat = in.LogFormat
 	return nil
 }
 
@@ -486,6 +487,7 @@ func autoConvert_config_KubeletConfiguration_To_v1beta1_KubeletConfiguration(in
 	out.EnforceNodeAllocatable = *(*[]string)(unsafe.Pointer(&in.EnforceNodeAllocatable))
 	out.ReservedSystemCPUs = in.ReservedSystemCPUs
 	out.ShowHiddenMetricsForVersion = in.ShowHiddenMetricsForVersion
+	out.LogFormat = in.LogFormat
 	return nil
 }
 

pkg/kubelet/apis/config/validation/BUILD

@@ -22,6 +22,7 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/util/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/validation:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
+        "//staging/src/k8s.io/component-base/logs:go_default_library",
         "//staging/src/k8s.io/component-base/metrics:go_default_library",
     ],
 )

pkg/kubelet/apis/config/validation/validation.go

@@ -23,6 +23,7 @@ import (
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 	utilvalidation "k8s.io/apimachinery/pkg/util/validation"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/component-base/logs"
 	"k8s.io/component-base/metrics"
 	"k8s.io/kubernetes/pkg/features"
 	kubeletconfig "k8s.io/kubernetes/pkg/kubelet/apis/config"
@@ -158,5 +159,12 @@ func ValidateKubeletConfiguration(kc *kubeletconfig.KubeletConfiguration) error
 		allErrors = append(allErrors, err)
 	}
 	allErrors = append(allErrors, metrics.ValidateShowHiddenMetricsVersion(kc.ShowHiddenMetricsForVersion)...)
+
+	logOption := logs.NewOptions()
+	if kc.LogFormat != "" {
+		logOption.LogFormat = kc.LogFormat
+	}
+	allErrors = append(allErrors, logOption.Validate()...)
+
 	return utilerrors.NewAggregate(allErrors)
 }