diff --git a/vendor/github.com/coreos/etcd/etcdserver/membership/store.go b/vendor/github.com/coreos/etcd/etcdserver/membership/store.go
new file mode 100644
index 0000000..d3f8f24
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/etcdserver/membership/store.go
@@ -0,0 +1,193 @@
+// Copyright 2016 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 membership
+
+import (
+	"encoding/json"
+	"fmt"
+	"path"
+
+	"github.com/coreos/etcd/mvcc/backend"
+	"github.com/coreos/etcd/pkg/types"
+	"github.com/coreos/etcd/store"
+
+	"github.com/coreos/go-semver/semver"
+)
+
+const (
+	attributesSuffix     = "attributes"
+	raftAttributesSuffix = "raftAttributes"
+
+	// the prefix for stroing membership related information in store provided by store pkg.
+	storePrefix = "/0"
+)
+
+var (
+	membersBucketName        = []byte("members")
+	membersRemovedBucketName = []byte("members_removed")
+	clusterBucketName        = []byte("cluster")
+
+	StoreMembersPrefix        = path.Join(storePrefix, "members")
+	storeRemovedMembersPrefix = path.Join(storePrefix, "removed_members")
+)
+
+func mustSaveMemberToBackend(be backend.Backend, m *Member) {
+	mkey := backendMemberKey(m.ID)
+	mvalue, err := json.Marshal(m)
+	if err != nil {
+		plog.Panicf("marshal raftAttributes should never fail: %v", err)
+	}
+
+	tx := be.BatchTx()
+	tx.Lock()
+	tx.UnsafePut(membersBucketName, mkey, mvalue)
+	tx.Unlock()
+}
+
+func mustDeleteMemberFromBackend(be backend.Backend, id types.ID) {
+	mkey := backendMemberKey(id)
+
+	tx := be.BatchTx()
+	tx.Lock()
+	tx.UnsafeDelete(membersBucketName, mkey)
+	tx.UnsafePut(membersRemovedBucketName, mkey, []byte("removed"))
+	tx.Unlock()
+}
+
+func mustSaveClusterVersionToBackend(be backend.Backend, ver *semver.Version) {
+	ckey := backendClusterVersionKey()
+
+	tx := be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+	tx.UnsafePut(clusterBucketName, ckey, []byte(ver.String()))
+}
+
+func mustSaveMemberToStore(s store.Store, m *Member) {
+	b, err := json.Marshal(m.RaftAttributes)
+	if err != nil {
+		plog.Panicf("marshal raftAttributes should never fail: %v", err)
+	}
+	p := path.Join(MemberStoreKey(m.ID), raftAttributesSuffix)
+	if _, err := s.Create(p, false, string(b), false, store.TTLOptionSet{ExpireTime: store.Permanent}); err != nil {
+		plog.Panicf("create raftAttributes should never fail: %v", err)
+	}
+}
+
+func mustDeleteMemberFromStore(s store.Store, id types.ID) {
+	if _, err := s.Delete(MemberStoreKey(id), true, true); err != nil {
+		plog.Panicf("delete member should never fail: %v", err)
+	}
+	if _, err := s.Create(RemovedMemberStoreKey(id), false, "", false, store.TTLOptionSet{ExpireTime: store.Permanent}); err != nil {
+		plog.Panicf("create removedMember should never fail: %v", err)
+	}
+}
+
+func mustUpdateMemberInStore(s store.Store, m *Member) {
+	b, err := json.Marshal(m.RaftAttributes)
+	if err != nil {
+		plog.Panicf("marshal raftAttributes should never fail: %v", err)
+	}
+	p := path.Join(MemberStoreKey(m.ID), raftAttributesSuffix)
+	if _, err := s.Update(p, string(b), store.TTLOptionSet{ExpireTime: store.Permanent}); err != nil {
+		plog.Panicf("update raftAttributes should never fail: %v", err)
+	}
+}
+
+func mustUpdateMemberAttrInStore(s store.Store, m *Member) {
+	b, err := json.Marshal(m.Attributes)
+	if err != nil {
+		plog.Panicf("marshal raftAttributes should never fail: %v", err)
+	}
+	p := path.Join(MemberStoreKey(m.ID), attributesSuffix)
+	if _, err := s.Set(p, false, string(b), store.TTLOptionSet{ExpireTime: store.Permanent}); err != nil {
+		plog.Panicf("update raftAttributes should never fail: %v", err)
+	}
+}
+
+func mustSaveClusterVersionToStore(s store.Store, ver *semver.Version) {
+	if _, err := s.Set(StoreClusterVersionKey(), false, ver.String(), store.TTLOptionSet{ExpireTime: store.Permanent}); err != nil {
+		plog.Panicf("save cluster version should never fail: %v", err)
+	}
+}
+
+// nodeToMember builds member from a key value node.
+// the child nodes of the given node MUST be sorted by key.
+func nodeToMember(n *store.NodeExtern) (*Member, error) {
+	m := &Member{ID: MustParseMemberIDFromKey(n.Key)}
+	attrs := make(map[string][]byte)
+	raftAttrKey := path.Join(n.Key, raftAttributesSuffix)
+	attrKey := path.Join(n.Key, attributesSuffix)
+	for _, nn := range n.Nodes {
+		if nn.Key != raftAttrKey && nn.Key != attrKey {
+			return nil, fmt.Errorf("unknown key %q", nn.Key)
+		}
+		attrs[nn.Key] = []byte(*nn.Value)
+	}
+	if data := attrs[raftAttrKey]; data != nil {
+		if err := json.Unmarshal(data, &m.RaftAttributes); err != nil {
+			return nil, fmt.Errorf("unmarshal raftAttributes error: %v", err)
+		}
+	} else {
+		return nil, fmt.Errorf("raftAttributes key doesn't exist")
+	}
+	if data := attrs[attrKey]; data != nil {
+		if err := json.Unmarshal(data, &m.Attributes); err != nil {
+			return m, fmt.Errorf("unmarshal attributes error: %v", err)
+		}
+	}
+	return m, nil
+}
+
+func backendMemberKey(id types.ID) []byte {
+	return []byte(id.String())
+}
+
+func backendClusterVersionKey() []byte {
+	return []byte("clusterVersion")
+}
+
+func mustCreateBackendBuckets(be backend.Backend) {
+	tx := be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+	tx.UnsafeCreateBucket(membersBucketName)
+	tx.UnsafeCreateBucket(membersRemovedBucketName)
+	tx.UnsafeCreateBucket(clusterBucketName)
+}
+
+func MemberStoreKey(id types.ID) string {
+	return path.Join(StoreMembersPrefix, id.String())
+}
+
+func StoreClusterVersionKey() string {
+	return path.Join(storePrefix, "version")
+}
+
+func MemberAttributesStorePath(id types.ID) string {
+	return path.Join(MemberStoreKey(id), attributesSuffix)
+}
+
+func MustParseMemberIDFromKey(key string) types.ID {
+	id, err := types.IDFromString(path.Base(key))
+	if err != nil {
+		plog.Panicf("unexpected parse member id error: %v", err)
+	}
+	return id
+}
+
+func RemovedMemberStoreKey(id types.ID) string {
+	return path.Join(storeRemovedMembersPrefix, id.String())
+}