From 8b5488ffa9b86ac612ea67bb89e47e1fe1e51c5b Mon Sep 17 00:00:00 2001
From: Xinzhao Xu <z2d@jifangcheng.com>
Date: Wed, 26 Apr 2023 10:22:28 +0800
Subject: [PATCH] [release-3.3] controller/cluster: retry when updating the
 KubeFedCluster conflicted (#5655)

controller/cluster: retry when updating the KubeFedCluster conflicted
---
 pkg/controller/cluster/cluster_controller.go |  5 +++++
 pkg/controller/cluster/join.go               | 21 ++++++++++----------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/pkg/controller/cluster/cluster_controller.go b/pkg/controller/cluster/cluster_controller.go
index 7d7812c4c..5b70d35e4 100644
--- a/pkg/controller/cluster/cluster_controller.go
+++ b/pkg/controller/cluster/cluster_controller.go
@@ -407,6 +407,11 @@ func (c *clusterController) syncCluster(key string) error {
 	} else { // join federation
 		_, err = c.joinFederation(clusterConfig, cluster.Name, cluster.Labels)
 		if err != nil {
+			if errors.IsConflict(err) {
+				klog.Warningf("update KubeFedCluster %s conflicted, retrying", cluster.Name)
+				return err
+			}
+
 			klog.Errorf("Failed to join federation for cluster %s, error %v", cluster.Name, err)
 
 			federationNotReadyCondition := clusterv1alpha1.ClusterCondition{
diff --git a/pkg/controller/cluster/join.go b/pkg/controller/cluster/join.go
index c008a5c2f..0d18a6be5 100644
--- a/pkg/controller/cluster/join.go
+++ b/pkg/controller/cluster/join.go
@@ -34,6 +34,7 @@ import (
 	kubeclient "k8s.io/client-go/kubernetes"
 	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/rest"
+	"k8s.io/client-go/util/retry"
 	"k8s.io/klog"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	fedapis "sigs.k8s.io/kubefed/pkg/apis"
@@ -199,25 +200,25 @@ func createKubeFedCluster(clusterConfig *rest.Config, client client.Client, join
 	case err == nil && errorOnExisting:
 		return nil, errors.Errorf("federated cluster %s already exists in host cluster", joiningClusterName)
 	case err == nil:
-		existingFedCluster.Spec = fedCluster.Spec
-		existingFedCluster.Labels = labels
-		err = client.Update(context.TODO(), existingFedCluster)
-		if err != nil {
+		if retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
+			if err = client.Get(context.TODO(), key, existingFedCluster); err != nil {
+				return err
+			}
+			existingFedCluster.Spec = fedCluster.Spec
+			existingFedCluster.Labels = labels
+			return client.Update(context.TODO(), existingFedCluster)
+		}); retryErr != nil {
 			klog.V(2).Infof("Could not update federated cluster %s due to %v", fedCluster.Name, err)
 			return nil, err
 		}
 		return existingFedCluster, nil
 	default:
-
-		err = checkWorkspaces(clusterConfig, client, fedCluster)
-
-		if err != nil {
+		if err = checkWorkspaces(clusterConfig, client, fedCluster); err != nil {
 			klog.V(2).Infof("Validate federated cluster %s failed due to %v", fedCluster.Name, err)
 			return nil, err
 		}
 
-		err = client.Create(context.TODO(), fedCluster)
-		if err != nil {
+		if err = client.Create(context.TODO(), fedCluster); err != nil {
 			klog.V(2).Infof("Could not create federated cluster %s due to %v", fedCluster.Name, err)
 			return nil, err
 		}