Merge pull request #37322 from xiang90/fix_36555

Automatic merge from submit-queue

etcd: fix rollback

fix #36555 

tested manually. worked.

/cc @mml @wojtek-t

cluster/images/etcd/migrate-if-needed.sh

@@ -230,7 +230,6 @@ if [ "${CURRENT_STORAGE}" = "etcd3" -a "${TARGET_STORAGE}" = "etcd2" ]; then
   rm -rf "${ROLLBACK_BACKUP_DIR}"
   mkdir -p "${ROLLBACK_BACKUP_DIR}"
   cp -r "${DATA_DIRECTORY}" "${ROLLBACK_BACKUP_DIR}"
-  rm -rf "${DATA_DIRECTORY}"/member/snap/*.snap
   echo "Performing etcd3 -> etcd2 rollback"
   ${ROLLBACK} --data-dir "${DATA_DIRECTORY}"
   if [ "$?" -ne "0" ]; then

cluster/images/etcd/rollback/rollback.go

@@ -38,6 +38,7 @@ import (
 	"github.com/coreos/etcd/store"
 	"github.com/coreos/etcd/wal"
 	"github.com/coreos/etcd/wal/walpb"
+	"github.com/coreos/go-semver/semver"
 	"github.com/golang/glog"
 )
 
@@ -263,6 +264,7 @@ func rebuild(datadir string) ([]byte, *raftpb.HardState, store.Store, error) {
 
 	cluster := membership.NewCluster("")
 	cluster.SetStore(st)
+	cluster.Recover(func(*semver.Version) {})
 
 	applier := etcdserver.NewApplierV2(st, cluster)
 	for _, ent := range ents {