add --logging-format flag to kubelet

cmd/kubelet/app/BUILD

@@ -111,6 +111,7 @@ go_library(
         "//staging/src/k8s.io/component-base/cli/flag:go_default_library",
         "//staging/src/k8s.io/component-base/configz:go_default_library",
         "//staging/src/k8s.io/component-base/featuregate:go_default_library",
+        "//staging/src/k8s.io/component-base/logs:go_default_library",
         "//staging/src/k8s.io/component-base/metrics:go_default_library",
         "//staging/src/k8s.io/component-base/metrics/legacyregistry:go_default_library",
         "//staging/src/k8s.io/component-base/version:go_default_library",

cmd/kubelet/app/options/options.go

@@ -540,6 +540,7 @@ func AddKubeletConfigFlags(mainfs *pflag.FlagSet, c *kubeletconfig.KubeletConfig
 	fs.StringSliceVar(&c.EnforceNodeAllocatable, "enforce-node-allocatable", c.EnforceNodeAllocatable, "A comma separated list of levels of node allocatable enforcement to be enforced by kubelet. Acceptable options are 'none', 'pods', 'system-reserved', and 'kube-reserved'. If the latter two options are specified, '--system-reserved-cgroup' and '--kube-reserved-cgroup' must also be set, respectively. If 'none' is specified, no additional options should be set. See https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/ for more details.")
 	fs.StringVar(&c.SystemReservedCgroup, "system-reserved-cgroup", c.SystemReservedCgroup, "Absolute name of the top level cgroup that is used to manage non-kubernetes components for which compute resources were reserved via '--system-reserved' flag. Ex. '/system-reserved'. [default='']")
 	fs.StringVar(&c.KubeReservedCgroup, "kube-reserved-cgroup", c.KubeReservedCgroup, "Absolute name of the top level cgroup that is used to manage kubernetes components for which compute resources were reserved via '--kube-reserved' flag. Ex. '/kube-reserved'. [default='']")
+	fs.StringVar(&c.LogFormat, "logging-format", c.LogFormat, "Set log format of Kubelet logging. Possible value: 'text'. Default: 'text'")
 
 	// Graduated experimental flags, kept for backward compatibility
 	fs.BoolVar(&c.KernelMemcgNotification, "experimental-kernel-memcg-notification", c.KernelMemcgNotification, "Use kernelMemcgNotification configuration, this flag will be removed in 1.23.")

cmd/kubelet/app/server.go

@@ -63,6 +63,7 @@ import (
 	cliflag "k8s.io/component-base/cli/flag"
 	"k8s.io/component-base/configz"
 	"k8s.io/component-base/featuregate"
+	"k8s.io/component-base/logs"
 	"k8s.io/component-base/metrics"
 	"k8s.io/component-base/metrics/legacyregistry"
 	"k8s.io/component-base/version"
@@ -403,6 +404,11 @@ func UnsecuredDependencies(s *options.KubeletServer, featureGate featuregate.Fea
 // Otherwise, the caller is assumed to have set up the Dependencies object and a default one will
 // not be generated.
 func Run(s *options.KubeletServer, kubeDeps *kubelet.Dependencies, featureGate featuregate.FeatureGate, stopCh <-chan struct{}) error {
+	logOption := logs.NewOptions()
+	if s.LogFormat != "" {
+		logOption.LogFormat = s.LogFormat
+	}
+	logOption.Apply()
 	// To help debugging, immediately log version
 	klog.Infof("Version: %+v", version.Get())
 	if err := initForOS(s.KubeletFlags.WindowsService); err != nil {

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)
 }

staging/src/k8s.io/kubelet/config/v1beta1/types.go

@@ -793,6 +793,11 @@ type KubeletConfiguration struct {
 	// Default: false
 	// +optional
 	KernelMemcgNotification bool `json:"kernelMemcgNotification,omitempty"`
+	// LogFormat specifies the structure of log messages.
+	// Refer [Logs Options](https://github.com/kubernetes/component-base/blob/master/logs/options.go) for more information.
+	// Default: "text"
+	// + optional
+	LogFormat string `json:"logFormat,omitempty"`
 }
 
 type KubeletAuthorizationMode string