Use PatchStatus to update node status in kubelet.

pkg/util/node/node.go

@@ -30,6 +30,7 @@ import (
 	metav1 "k8s.io/kubernetes/pkg/apis/meta/v1"
 	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/release_1_5"
 	"k8s.io/kubernetes/pkg/types"
+	"k8s.io/kubernetes/pkg/util/strategicpatch"
 )
 
 const (
@@ -153,3 +154,32 @@ func SetNodeCondition(c clientset.Interface, node types.NodeName, condition v1.N
 	_, err = c.Core().Nodes().PatchStatus(string(node), patch)
 	return err
 }
+
+// PatchNodeStatus patches node status.
+func PatchNodeStatus(c clientset.Interface, nodeName types.NodeName, oldNode *v1.Node, newNode *v1.Node) (*v1.Node, error) {
+	oldData, err := json.Marshal(oldNode)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal old node %#v for node %q: %v", oldNode, nodeName, err)
+	}
+
+	// Reset spec to make sure only patch for Status or ObjectMeta is generated.
+	// Note that we don't reset ObjectMeta here, because:
+	// 1. This aligns with Nodes().UpdateStatus().
+	// 2. Some component does use this to update node annotations.
+	newNode.Spec = oldNode.Spec
+	newData, err := json.Marshal(newNode)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal new node %#v for node %q: %v", newNode, nodeName, err)
+	}
+
+	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, v1.Node{})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create patch for node %q: %v", nodeName, err)
+	}
+
+	updatedNode, err := c.Core().Nodes().Patch(string(nodeName), api.StrategicMergePatchType, patchBytes, "status")
+	if err != nil {
+		return nil, fmt.Errorf("failed to patch status %q for node %q: %v", patchBytes, nodeName, err)
+	}
+	return updatedNode, nil
+}