Retry when update node with configmap fails.

cmd/kubeadm/app/constants/constants.go

@@ -124,6 +124,8 @@ const (
 	DiscoveryRetryInterval = 5 * time.Second
 	// MarkMasterTimeout specifies how long kubeadm should wait for applying the label and taint on the master before timing out
 	MarkMasterTimeout = 2 * time.Minute
+	// UpdateNodeTimeout specifies how long kubeadm should wait for updating node with the initial remote configuration of kubelet before timing out
+	UpdateNodeTimeout = 2 * time.Minute
 
 	// MinimumAddressesInServiceSubnet defines minimum amount of nodes the Service subnet should allow.
 	// We need at least ten, because the DNS service is always at the tenth cluster clusterIP
@@ -143,10 +145,10 @@ const (
 	// MasterConfigurationConfigMapKey specifies in what ConfigMap key the master configuration should be stored
 	MasterConfigurationConfigMapKey = "MasterConfiguration"
 
-	// KubeletBaseConfigurationConfigMap specifies in what ConfigMap in the kube-system namespace the initial remote configuration should be stored
+	// KubeletBaseConfigurationConfigMap specifies in what ConfigMap in the kube-system namespace the initial remote configuration of kubelet should be stored
 	KubeletBaseConfigurationConfigMap = "kubelet-base-config-1.9"
 
-	// KubeletBaseConfigurationConfigMapKey specifies in what ConfigMap key the initial remote configuration should be stored
+	// KubeletBaseConfigurationConfigMapKey specifies in what ConfigMap key the initial remote configuration of kubelet should be stored
 	// TODO: Use the constant ("kubelet.config.k8s.io") defined in pkg/kubelet/kubeletconfig/util/keys/keys.go
 	// after https://github.com/kubernetes/kubernetes/pull/53833 being merged.
 	KubeletBaseConfigurationConfigMapKey = "kubelet"

cmd/kubeadm/app/phases/kubelet/kubelet.go

@@ -26,6 +26,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/strategicpatch"
+	"k8s.io/apimachinery/pkg/util/wait"
 	clientset "k8s.io/client-go/kubernetes"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
@@ -68,41 +69,45 @@ func CreateBaseKubeletConfiguration(cfg *kubeadmapi.MasterConfiguration, client
 
 // UpdateNodeWithConfigMap updates node ConfigSource with KubeletBaseConfigurationConfigMap
 func UpdateNodeWithConfigMap(client clientset.Interface, nodeName string) error {
-	node, err := client.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
-	if err != nil {
-		return err
-	}
+	// Loop on every falsy return. Return with an error if raised. Exit successfully if true is returned.
+	return wait.Poll(kubeadmconstants.APICallRetryInterval, kubeadmconstants.UpdateNodeTimeout, func() (bool, error) {
+		node, err := client.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+		if err != nil {
+			return false, nil
+		}
 
-	oldData, err := json.Marshal(node)
-	if err != nil {
-		return err
-	}
+		oldData, err := json.Marshal(node)
+		if err != nil {
+			return false, err
+		}
 
-	kubeletCfg, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(kubeadmconstants.KubeletBaseConfigurationConfigMap, metav1.GetOptions{})
-	if err != nil {
-		return err
-	}
+		kubeletCfg, err := client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(kubeadmconstants.KubeletBaseConfigurationConfigMap, metav1.GetOptions{})
+		if err != nil {
+			return false, nil
+		}
 
-	node.Spec.ConfigSource.ConfigMapRef.UID = kubeletCfg.UID
+		node.Spec.ConfigSource.ConfigMapRef.UID = kubeletCfg.UID
 
-	newData, err := json.Marshal(node)
-	if err != nil {
-		return err
-	}
+		newData, err := json.Marshal(node)
+		if err != nil {
+			return false, err
+		}
 
-	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, v1.Node{})
-	if err != nil {
-		return err
-	}
+		patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, v1.Node{})
+		if err != nil {
+			return false, err
+		}
 
-	if _, err := client.CoreV1().Nodes().Patch(node.Name, types.StrategicMergePatchType, patchBytes); err != nil {
-		if apierrs.IsConflict(err) {
-			fmt.Println("Temporarily unable to update node metadata due to conflict (will retry)")
+		if _, err := client.CoreV1().Nodes().Patch(node.Name, types.StrategicMergePatchType, patchBytes); err != nil {
+			if apierrs.IsConflict(err) {
+				fmt.Println("Temporarily unable to update node metadata due to conflict (will retry)")
+				return false, nil
+			}
+			return false, err
 		}
-		return err
-	}
 
-	return nil
+		return true, nil
+	})
 }
 
 // createKubeletBaseConfigMapRBACRules creates the RBAC rules for exposing the base kubelet ConfigMap in the kube-system namespace to unauthenticated users