diff --git a/vendor/go.etcd.io/etcd/etcdserver/consistent_index.go b/vendor/go.etcd.io/etcd/etcdserver/consistent_index.go
new file mode 100644
index 0000000..d513f67
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/consistent_index.go
@@ -0,0 +1,33 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"sync/atomic"
+)
+
+// consistentIndex represents the offset of an entry in a consistent replica log.
+// It implements the mvcc.ConsistentIndexGetter interface.
+// It is always set to the offset of current entry before executing the entry,
+// so ConsistentWatchableKV could get the consistent index from it.
+type consistentIndex uint64
+
+func (i *consistentIndex) setConsistentIndex(v uint64) {
+	atomic.StoreUint64((*uint64)(i), v)
+}
+
+func (i *consistentIndex) ConsistentIndex() uint64 {
+	return atomic.LoadUint64((*uint64)(i))
+}