Don't try to read token hash and cluster id during cluster-reset

pkg/etcd/etcd.go

@@ -354,10 +354,10 @@ func (e *ETCD) Reset(ctx context.Context, rebootstrap func() error) error {
 	// If asked to restore from a snapshot, do so
 	if e.config.ClusterResetRestorePath != "" {
 		if e.config.EtcdS3 {
+			logrus.Infof("Retrieving etcd snapshot %s from S3", e.config.ClusterResetRestorePath)
 			if err := e.initS3IfNil(ctx); err != nil {
 				return err
 			}
-			logrus.Infof("Retrieving etcd snapshot %s from S3", e.config.ClusterResetRestorePath)
 			if err := e.s3.Download(ctx); err != nil {
 				return err
 			}

pkg/etcd/s3.go

@@ -13,7 +13,6 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -28,6 +27,7 @@ import (
 	"github.com/sirupsen/logrus"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/wait"
 )
 
 var (
@@ -100,30 +100,40 @@ func NewS3(ctx context.Context, config *config.Control) (*S3, error) {
 	}
 	logrus.Infof("S3 bucket %s exists", config.EtcdS3BucketName)
 
-	for config.Runtime.Core == nil {
-		runtime.Gosched()
+	s3 := &S3{
+		config:   config,
+		client:   c,
+		nodeName: os.Getenv("NODE_NAME"),
 	}
 
-	// cluster id hack: see https://groups.google.com/forum/#!msg/kubernetes-sig-architecture/mVGobfD4TpY/nkdbkX1iBwAJ
-	var clusterID string
-	if ns, err := config.Runtime.Core.Core().V1().Namespace().Get(metav1.NamespaceSystem, metav1.GetOptions{}); err != nil {
-		logrus.Warnf("Failed to set cluster ID: %v", err)
+	if config.ClusterReset {
+		logrus.Debug("Skip setting S3 snapshot cluster ID and token during cluster-reset")
 	} else {
-		clusterID = string(ns.UID)
-	}
+		if err := wait.PollImmediateUntilWithContext(ctx, time.Second, func(ctx context.Context) (bool, error) {
+			if config.Runtime.Core == nil {
+				return false, nil
+			}
 
-	tokenHash, err := util.GetTokenHash(config)
-	if err != nil {
-		return nil, errors.Wrap(err, "failed to get server token hash for etcd snapshot")
+			// cluster id hack: see https://groups.google.com/forum/#!msg/kubernetes-sig-architecture/mVGobfD4TpY/nkdbkX1iBwAJ
+			ns, err := config.Runtime.Core.Core().V1().Namespace().Get(metav1.NamespaceSystem, metav1.GetOptions{})
+			if err != nil {
+				return false, errors.Wrap(err, "failed to set S3 snapshot cluster ID")
+			}
+			s3.clusterID = string(ns.UID)
+
+			tokenHash, err := util.GetTokenHash(config)
+			if err != nil {
+				return false, errors.Wrap(err, "failed to set S3 snapshot server token hash")
+			}
+			s3.tokenHash = tokenHash
+
+			return true, nil
+		}); err != nil {
+			return nil, err
+		}
 	}
 
-	return &S3{
-		config:    config,
-		client:    c,
-		clusterID: clusterID,
-		tokenHash: tokenHash,
-		nodeName:  os.Getenv("NODE_NAME"),
-	}, nil
+	return s3, nil
 }
 
 // upload uploads the given snapshot to the configured S3
@@ -229,7 +239,6 @@ func (s *S3) Download(ctx context.Context) error {
 	snapshotFile := filepath.Join(snapshotDir, s.config.ClusterResetRestorePath)
 	metadataFile := filepath.Join(snapshotDir, "..", metadataDir, s.config.ClusterResetRestorePath)
 
-	logrus.Debugf("Downloading snapshot from s3://%s/%s", s.config.EtcdS3BucketName, snapshotKey)
 	if err := s.downloadSnapshot(ctx, snapshotKey, snapshotFile); err != nil {
 		return err
 	}
@@ -243,6 +252,7 @@ func (s *S3) Download(ctx context.Context) error {
 
 // downloadSnapshot downloads the snapshot file from S3 using the minio API.
 func (s *S3) downloadSnapshot(ctx context.Context, key, file string) error {
+	logrus.Debugf("Downloading snapshot from s3://%s/%s", s.config.EtcdS3BucketName, key)
 	ctx, cancel := context.WithTimeout(ctx, s.config.EtcdS3Timeout)
 	defer cancel()
 	defer os.Chmod(file, 0600)