server: try updating storage schema during bootstrap

server/etcdserver/bootstrap.go

@@ -100,6 +100,7 @@ func bootstrap(cfg config.ServerConfig) (b *bootstrappedServer, err error) {
 	if terr := fileutil.TouchDirAll(cfg.MemberDir()); terr != nil {
 		return nil, fmt.Errorf("cannot access member directory: %v", terr)
 	}
+	boostrapStorageSchema(cfg.Logger, be)
 	b.prt = prt
 	b.ci = ci
 	b.st = st
@@ -340,6 +341,14 @@ func bootstrapWithWAL(cfg config.ServerConfig, st v2store.Store, be backend.Back
 	return r, nil
 }
 
+func boostrapStorageSchema(lg *zap.Logger, be backend.Backend) {
+	err := schema.UpdateStorageSchema(lg, be.BatchTx())
+	if err != nil {
+		// Can fail as it requires all fields to be set. Fields introduced in v3.5 will be set only after snapshot.
+		lg.Warn("failed to update storage version, will try again after first wal snapshot", zap.Error(err))
+	}
+}
+
 func bootstrapRaftFromCluster(cfg config.ServerConfig, cl *membership.RaftCluster, ids []types.ID) *bootstrappedRaft {
 	member := cl.MemberByName(cfg.Name)
 	id := member.ID

server/etcdserver/server.go

@@ -2136,6 +2136,8 @@ func (s *EtcdServer) snapshot(snapi uint64, confState raftpb.ConfState) {
 			"saved snapshot",
 			zap.Uint64("snapshot-index", snap.Metadata.Index),
 		)
+		// Update storage schema after snapshot as fields introduced in v3.5 should be set.
+		// Remove in v3.7
 		s.updateStorageSchema.Do(func() {
 			err := schema.UpdateStorageSchema(s.lg, s.be.BatchTx())
 			if err != nil {