diff --git a/staging/src/k8s.io/metrics/pkg/apis/metrics/types.go b/staging/src/k8s.io/metrics/pkg/apis/metrics/types.go
index 10dc8525aa9..f1c58c76840 100644
--- a/staging/src/k8s.io/metrics/pkg/apis/metrics/types.go
+++ b/staging/src/k8s.io/metrics/pkg/apis/metrics/types.go
@@ -30,6 +30,9 @@ import (
 // NodeMetrics sets resource usage metrics of a node.
 type NodeMetrics struct {
 	metav1.TypeMeta
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta
 
 	// The following fields define time interval from which metrics were
@@ -62,6 +65,9 @@ type NodeMetricsList struct {
 // PodMetrics sets resource usage metrics of a pod.
 type PodMetrics struct {
 	metav1.TypeMeta
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta
 
 	// The following fields define time interval from which metrics were
diff --git a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/generated.proto b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/generated.proto
index dbce364f037..1810fb03864 100644
--- a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/generated.proto
+++ b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/generated.proto
@@ -41,6 +41,9 @@ message ContainerMetrics {
 
 // NodeMetrics sets resource usage metrics of a node.
 message NodeMetrics {
+  // Standard object's metadata.
+  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+  // +optional
   optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;
 
   // The following fields define time interval from which metrics were
@@ -65,6 +68,9 @@ message NodeMetricsList {
 
 // PodMetrics sets resource usage metrics of a pod.
 message PodMetrics {
+  // Standard object's metadata.
+  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+  // +optional
   optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;
 
   // The following fields define time interval from which metrics were
diff --git a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/types.go b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/types.go
index 10d6cd8656a..871a3b1777b 100644
--- a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/types.go
+++ b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1alpha1/types.go
@@ -17,7 +17,7 @@ limitations under the License.
 package v1alpha1
 
 import (
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -29,7 +29,10 @@ import (
 
 // NodeMetrics sets resource usage metrics of a node.
 type NodeMetrics struct {
-	metav1.TypeMeta   `json:",inline"`
+	metav1.TypeMeta `json:",inline"`
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 
 	// The following fields define time interval from which metrics were
@@ -61,7 +64,10 @@ type NodeMetricsList struct {
 
 // PodMetrics sets resource usage metrics of a pod.
 type PodMetrics struct {
-	metav1.TypeMeta   `json:",inline"`
+	metav1.TypeMeta `json:",inline"`
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 
 	// The following fields define time interval from which metrics were
diff --git a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/generated.proto b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/generated.proto
index 09f203865a6..a72d2eb4048 100644
--- a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/generated.proto
+++ b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/generated.proto
@@ -41,6 +41,9 @@ message ContainerMetrics {
 
 // NodeMetrics sets resource usage metrics of a node.
 message NodeMetrics {
+  // Standard object's metadata.
+  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+  // +optional
   optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;
 
   // The following fields define time interval from which metrics were
@@ -65,6 +68,9 @@ message NodeMetricsList {
 
 // PodMetrics sets resource usage metrics of a pod.
 message PodMetrics {
+  // Standard object's metadata.
+  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+  // +optional
   optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;
 
   // The following fields define time interval from which metrics were
diff --git a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/types.go b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/types.go
index c6ea24a309e..530797b5bf6 100644
--- a/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/types.go
+++ b/staging/src/k8s.io/metrics/pkg/apis/metrics/v1beta1/types.go
@@ -17,7 +17,7 @@ limitations under the License.
 package v1beta1
 
 import (
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -29,7 +29,10 @@ import (
 
 // NodeMetrics sets resource usage metrics of a node.
 type NodeMetrics struct {
-	metav1.TypeMeta   `json:",inline"`
+	metav1.TypeMeta `json:",inline"`
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 
 	// The following fields define time interval from which metrics were
@@ -61,7 +64,10 @@ type NodeMetricsList struct {
 
 // PodMetrics sets resource usage metrics of a pod.
 type PodMetrics struct {
-	metav1.TypeMeta   `json:",inline"`
+	metav1.TypeMeta `json:",inline"`
+	// Standard object's metadata.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
+	// +optional
 	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 
 	// The following fields define time interval from which metrics were