Merge pull request kubernetes#130782 from BernardMC/master

Kubeadm issue kubernetes#3152 ControlPlane node setup failing with "etcdserver: can only promote a learner member"

Author: k8s-ci-robot

cmd/kubeadm/app/util/etcd/etcd.go

@@ -576,6 +576,15 @@ func (c *Client) MemberPromote(learnerID uint64) error {
 			ctx, cancel := context.WithTimeout(context.Background(), etcdTimeout)
 			defer cancel()
 
+			isLearner, err := c.isLearner(learnerID)
+			if err != nil {
+				return false, err
+			}
+			if !isLearner {
+				klog.V(1).Infof("[etcd] Member %s was already promoted.", strconv.FormatUint(learnerID, 16))
+				return true, nil
+			}
+
 			_, err = cli.MemberPromote(ctx, learnerID)
 			if err == nil {
 				klog.V(1).Infof("[etcd] The learner was promoted as a voting member: %s", strconv.FormatUint(learnerID, 16))