nodelifecycle controller: reconcile node OS/arch labels

pkg/controller/controller_utils.go

@@ -88,6 +88,12 @@ var UpdateTaintBackoff = wait.Backoff{
 	Jitter:   1.0,
 }
 
+var UpdateLabelBackoff = wait.Backoff{
+	Steps:    5,
+	Duration: 100 * time.Millisecond,
+	Jitter:   1.0,
+}
+
 var (
 	KeyFunc = cache.DeletionHandlingMetaNamespaceKeyFunc
 )
@@ -1045,3 +1051,48 @@ func ComputeHash(template *v1.PodTemplateSpec, collisionCount *int32) string {
 
 	return rand.SafeEncodeString(fmt.Sprint(podTemplateSpecHasher.Sum32()))
 }
+
+func AddOrUpdateLabelsOnNode(kubeClient clientset.Interface, nodeName string, labelsToUpdate map[string]string) error {
+	firstTry := true
+	return clientretry.RetryOnConflict(UpdateLabelBackoff, func() error {
+		var err error
+		var node *v1.Node
+		// First we try getting node from the API server cache, as it's cheaper. If it fails
+		// we get it from etcd to be sure to have fresh data.
+		if firstTry {
+			node, err = kubeClient.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{ResourceVersion: "0"})
+			firstTry = false
+		} else {
+			node, err = kubeClient.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+		}
+		if err != nil {
+			return err
+		}
+
+		// Make a copy of the node and update the labels.
+		newNode := node.DeepCopy()
+		if newNode.Labels == nil {
+			newNode.Labels = make(map[string]string)
+		}
+		for key, value := range labelsToUpdate {
+			newNode.Labels[key] = value
+		}
+
+		oldData, err := json.Marshal(node)
+		if err != nil {
+			return fmt.Errorf("failed to marshal the existing node %#v: %v", node, err)
+		}
+		newData, err := json.Marshal(newNode)
+		if err != nil {
+			return fmt.Errorf("failed to marshal the new node %#v: %v", newNode, err)
+		}
+		patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, &v1.Node{})
+		if err != nil {
+			return fmt.Errorf("failed to create a two-way merge patch: %v", err)
+		}
+		if _, err := kubeClient.CoreV1().Nodes().Patch(node.Name, types.StrategicMergePatchType, patchBytes); err != nil {
+			return fmt.Errorf("failed to patch the node: %v", err)
+		}
+		return nil
+	})
+}