diff --git a/vendor/go.etcd.io/etcd/embed/serve.go b/vendor/go.etcd.io/etcd/embed/serve.go
new file mode 100644
index 0000000..a3b20c4
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/embed/serve.go
@@ -0,0 +1,435 @@
+// 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 embed
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	defaultLog "log"
+	"net"
+	"net/http"
+	"strings"
+
+	"go.etcd.io/etcd/clientv3/credentials"
+	"go.etcd.io/etcd/etcdserver"
+	"go.etcd.io/etcd/etcdserver/api/v3client"
+	"go.etcd.io/etcd/etcdserver/api/v3election"
+	"go.etcd.io/etcd/etcdserver/api/v3election/v3electionpb"
+	v3electiongw "go.etcd.io/etcd/etcdserver/api/v3election/v3electionpb/gw"
+	"go.etcd.io/etcd/etcdserver/api/v3lock"
+	"go.etcd.io/etcd/etcdserver/api/v3lock/v3lockpb"
+	v3lockgw "go.etcd.io/etcd/etcdserver/api/v3lock/v3lockpb/gw"
+	"go.etcd.io/etcd/etcdserver/api/v3rpc"
+	etcdservergw "go.etcd.io/etcd/etcdserver/etcdserverpb/gw"
+	"go.etcd.io/etcd/pkg/debugutil"
+	"go.etcd.io/etcd/pkg/httputil"
+	"go.etcd.io/etcd/pkg/transport"
+
+	gw "github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"github.com/soheilhy/cmux"
+	"github.com/tmc/grpc-websocket-proxy/wsproxy"
+	"go.uber.org/zap"
+	"golang.org/x/net/trace"
+	"google.golang.org/grpc"
+)
+
+type serveCtx struct {
+	lg       *zap.Logger
+	l        net.Listener
+	addr     string
+	network  string
+	secure   bool
+	insecure bool
+
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	userHandlers    map[string]http.Handler
+	serviceRegister func(*grpc.Server)
+	serversC        chan *servers
+}
+
+type servers struct {
+	secure bool
+	grpc   *grpc.Server
+	http   *http.Server
+}
+
+func newServeCtx(lg *zap.Logger) *serveCtx {
+	ctx, cancel := context.WithCancel(context.Background())
+	return &serveCtx{
+		lg:           lg,
+		ctx:          ctx,
+		cancel:       cancel,
+		userHandlers: make(map[string]http.Handler),
+		serversC:     make(chan *servers, 2), // in case sctx.insecure,sctx.secure true
+	}
+}
+
+// serve accepts incoming connections on the listener l,
+// creating a new service goroutine for each. The service goroutines
+// read requests and then call handler to reply to them.
+func (sctx *serveCtx) serve(
+	s *etcdserver.EtcdServer,
+	tlsinfo *transport.TLSInfo,
+	handler http.Handler,
+	errHandler func(error),
+	gopts ...grpc.ServerOption) (err error) {
+	logger := defaultLog.New(ioutil.Discard, "etcdhttp", 0)
+	<-s.ReadyNotify()
+
+	if sctx.lg == nil {
+		plog.Info("ready to serve client requests")
+	}
+
+	m := cmux.New(sctx.l)
+	v3c := v3client.New(s)
+	servElection := v3election.NewElectionServer(v3c)
+	servLock := v3lock.NewLockServer(v3c)
+
+	var gs *grpc.Server
+	defer func() {
+		if err != nil && gs != nil {
+			gs.Stop()
+		}
+	}()
+
+	if sctx.insecure {
+		gs = v3rpc.Server(s, nil, gopts...)
+		v3electionpb.RegisterElectionServer(gs, servElection)
+		v3lockpb.RegisterLockServer(gs, servLock)
+		if sctx.serviceRegister != nil {
+			sctx.serviceRegister(gs)
+		}
+		grpcl := m.Match(cmux.HTTP2())
+		go func() { errHandler(gs.Serve(grpcl)) }()
+
+		var gwmux *gw.ServeMux
+		if s.Cfg.EnableGRPCGateway {
+			gwmux, err = sctx.registerGateway([]grpc.DialOption{grpc.WithInsecure()})
+			if err != nil {
+				return err
+			}
+		}
+
+		httpmux := sctx.createMux(gwmux, handler)
+
+		srvhttp := &http.Server{
+			Handler:  createAccessController(sctx.lg, s, httpmux),
+			ErrorLog: logger, // do not log user error
+		}
+		httpl := m.Match(cmux.HTTP1())
+		go func() { errHandler(srvhttp.Serve(httpl)) }()
+
+		sctx.serversC <- &servers{grpc: gs, http: srvhttp}
+		if sctx.lg != nil {
+			sctx.lg.Info(
+				"serving client traffic insecurely; this is strongly discouraged!",
+				zap.String("address", sctx.l.Addr().String()),
+			)
+		} else {
+			plog.Noticef("serving insecure client requests on %s, this is strongly discouraged!", sctx.l.Addr().String())
+		}
+	}
+
+	if sctx.secure {
+		tlscfg, tlsErr := tlsinfo.ServerConfig()
+		if tlsErr != nil {
+			return tlsErr
+		}
+		gs = v3rpc.Server(s, tlscfg, gopts...)
+		v3electionpb.RegisterElectionServer(gs, servElection)
+		v3lockpb.RegisterLockServer(gs, servLock)
+		if sctx.serviceRegister != nil {
+			sctx.serviceRegister(gs)
+		}
+		handler = grpcHandlerFunc(gs, handler)
+
+		var gwmux *gw.ServeMux
+		if s.Cfg.EnableGRPCGateway {
+			dtls := tlscfg.Clone()
+			// trust local server
+			dtls.InsecureSkipVerify = true
+			bundle := credentials.NewBundle(credentials.Config{TLSConfig: dtls})
+			opts := []grpc.DialOption{grpc.WithTransportCredentials(bundle.TransportCredentials())}
+			gwmux, err = sctx.registerGateway(opts)
+			if err != nil {
+				return err
+			}
+		}
+
+		var tlsl net.Listener
+		tlsl, err = transport.NewTLSListener(m.Match(cmux.Any()), tlsinfo)
+		if err != nil {
+			return err
+		}
+		// TODO: add debug flag; enable logging when debug flag is set
+		httpmux := sctx.createMux(gwmux, handler)
+
+		srv := &http.Server{
+			Handler:   createAccessController(sctx.lg, s, httpmux),
+			TLSConfig: tlscfg,
+			ErrorLog:  logger, // do not log user error
+		}
+		go func() { errHandler(srv.Serve(tlsl)) }()
+
+		sctx.serversC <- &servers{secure: true, grpc: gs, http: srv}
+		if sctx.lg != nil {
+			sctx.lg.Info(
+				"serving client traffic securely",
+				zap.String("address", sctx.l.Addr().String()),
+			)
+		} else {
+			plog.Infof("serving client requests on %s", sctx.l.Addr().String())
+		}
+	}
+
+	close(sctx.serversC)
+	return m.Serve()
+}
+
+// grpcHandlerFunc returns an http.Handler that delegates to grpcServer on incoming gRPC
+// connections or otherHandler otherwise. Given in gRPC docs.
+func grpcHandlerFunc(grpcServer *grpc.Server, otherHandler http.Handler) http.Handler {
+	if otherHandler == nil {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			grpcServer.ServeHTTP(w, r)
+		})
+	}
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.ProtoMajor == 2 && strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
+			grpcServer.ServeHTTP(w, r)
+		} else {
+			otherHandler.ServeHTTP(w, r)
+		}
+	})
+}
+
+type registerHandlerFunc func(context.Context, *gw.ServeMux, *grpc.ClientConn) error
+
+func (sctx *serveCtx) registerGateway(opts []grpc.DialOption) (*gw.ServeMux, error) {
+	ctx := sctx.ctx
+
+	addr := sctx.addr
+	if network := sctx.network; network == "unix" {
+		// explicitly define unix network for gRPC socket support
+		addr = fmt.Sprintf("%s://%s", network, addr)
+	}
+
+	conn, err := grpc.DialContext(ctx, addr, opts...)
+	if err != nil {
+		return nil, err
+	}
+	gwmux := gw.NewServeMux()
+
+	handlers := []registerHandlerFunc{
+		etcdservergw.RegisterKVHandler,
+		etcdservergw.RegisterWatchHandler,
+		etcdservergw.RegisterLeaseHandler,
+		etcdservergw.RegisterClusterHandler,
+		etcdservergw.RegisterMaintenanceHandler,
+		etcdservergw.RegisterAuthHandler,
+		v3lockgw.RegisterLockHandler,
+		v3electiongw.RegisterElectionHandler,
+	}
+	for _, h := range handlers {
+		if err := h(ctx, gwmux, conn); err != nil {
+			return nil, err
+		}
+	}
+	go func() {
+		<-ctx.Done()
+		if cerr := conn.Close(); cerr != nil {
+			if sctx.lg != nil {
+				sctx.lg.Warn(
+					"failed to close connection",
+					zap.String("address", sctx.l.Addr().String()),
+					zap.Error(cerr),
+				)
+			} else {
+				plog.Warningf("failed to close conn to %s: %v", sctx.l.Addr().String(), cerr)
+			}
+		}
+	}()
+
+	return gwmux, nil
+}
+
+func (sctx *serveCtx) createMux(gwmux *gw.ServeMux, handler http.Handler) *http.ServeMux {
+	httpmux := http.NewServeMux()
+	for path, h := range sctx.userHandlers {
+		httpmux.Handle(path, h)
+	}
+
+	if gwmux != nil {
+		httpmux.Handle(
+			"/v3/",
+			wsproxy.WebsocketProxy(
+				gwmux,
+				wsproxy.WithRequestMutator(
+					// Default to the POST method for streams
+					func(_ *http.Request, outgoing *http.Request) *http.Request {
+						outgoing.Method = "POST"
+						return outgoing
+					},
+				),
+			),
+		)
+	}
+	if handler != nil {
+		httpmux.Handle("/", handler)
+	}
+	return httpmux
+}
+
+// createAccessController wraps HTTP multiplexer:
+// - mutate gRPC gateway request paths
+// - check hostname whitelist
+// client HTTP requests goes here first
+func createAccessController(lg *zap.Logger, s *etcdserver.EtcdServer, mux *http.ServeMux) http.Handler {
+	return &accessController{lg: lg, s: s, mux: mux}
+}
+
+type accessController struct {
+	lg  *zap.Logger
+	s   *etcdserver.EtcdServer
+	mux *http.ServeMux
+}
+
+func (ac *accessController) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	// redirect for backward compatibilities
+	if req != nil && req.URL != nil && strings.HasPrefix(req.URL.Path, "/v3beta/") {
+		req.URL.Path = strings.Replace(req.URL.Path, "/v3beta/", "/v3/", 1)
+	}
+
+	if req.TLS == nil { // check origin if client connection is not secure
+		host := httputil.GetHostname(req)
+		if !ac.s.AccessController.IsHostWhitelisted(host) {
+			if ac.lg != nil {
+				ac.lg.Warn(
+					"rejecting HTTP request to prevent DNS rebinding attacks",
+					zap.String("host", host),
+				)
+			} else {
+				plog.Warningf("rejecting HTTP request from %q to prevent DNS rebinding attacks", host)
+			}
+			// TODO: use Go's "http.StatusMisdirectedRequest" (421)
+			// https://github.com/golang/go/commit/4b8a7eafef039af1834ef9bfa879257c4a72b7b5
+			http.Error(rw, errCVE20185702(host), 421)
+			return
+		}
+	} else if ac.s.Cfg.ClientCertAuthEnabled && ac.s.Cfg.EnableGRPCGateway &&
+		ac.s.AuthStore().IsAuthEnabled() && strings.HasPrefix(req.URL.Path, "/v3/") {
+		for _, chains := range req.TLS.VerifiedChains {
+			if len(chains) < 1 {
+				continue
+			}
+			if len(chains[0].Subject.CommonName) != 0 {
+				http.Error(rw, "CommonName of client sending a request against gateway will be ignored and not used as expected", 400)
+				return
+			}
+		}
+	}
+
+	// Write CORS header.
+	if ac.s.AccessController.OriginAllowed("*") {
+		addCORSHeader(rw, "*")
+	} else if origin := req.Header.Get("Origin"); ac.s.OriginAllowed(origin) {
+		addCORSHeader(rw, origin)
+	}
+
+	if req.Method == "OPTIONS" {
+		rw.WriteHeader(http.StatusOK)
+		return
+	}
+
+	ac.mux.ServeHTTP(rw, req)
+}
+
+// addCORSHeader adds the correct cors headers given an origin
+func addCORSHeader(w http.ResponseWriter, origin string) {
+	w.Header().Add("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
+	w.Header().Add("Access-Control-Allow-Origin", origin)
+	w.Header().Add("Access-Control-Allow-Headers", "accept, content-type, authorization")
+}
+
+// https://github.com/transmission/transmission/pull/468
+func errCVE20185702(host string) string {
+	return fmt.Sprintf(`
+etcd received your request, but the Host header was unrecognized.
+
+To fix this, choose one of the following options:
+- Enable TLS, then any HTTPS request will be allowed.
+- Add the hostname you want to use to the whitelist in settings.
+  - e.g. etcd --host-whitelist %q
+
+This requirement has been added to help prevent "DNS Rebinding" attacks (CVE-2018-5702).
+`, host)
+}
+
+// WrapCORS wraps existing handler with CORS.
+// TODO: deprecate this after v2 proxy deprecate
+func WrapCORS(cors map[string]struct{}, h http.Handler) http.Handler {
+	return &corsHandler{
+		ac: &etcdserver.AccessController{CORS: cors},
+		h:  h,
+	}
+}
+
+type corsHandler struct {
+	ac *etcdserver.AccessController
+	h  http.Handler
+}
+
+func (ch *corsHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if ch.ac.OriginAllowed("*") {
+		addCORSHeader(rw, "*")
+	} else if origin := req.Header.Get("Origin"); ch.ac.OriginAllowed(origin) {
+		addCORSHeader(rw, origin)
+	}
+
+	if req.Method == "OPTIONS" {
+		rw.WriteHeader(http.StatusOK)
+		return
+	}
+
+	ch.h.ServeHTTP(rw, req)
+}
+
+func (sctx *serveCtx) registerUserHandler(s string, h http.Handler) {
+	if sctx.userHandlers[s] != nil {
+		if sctx.lg != nil {
+			sctx.lg.Warn("path is already registered by user handler", zap.String("path", s))
+		} else {
+			plog.Warningf("path %s already registered by user handler", s)
+		}
+		return
+	}
+	sctx.userHandlers[s] = h
+}
+
+func (sctx *serveCtx) registerPprof() {
+	for p, h := range debugutil.PProfHandlers() {
+		sctx.registerUserHandler(p, h)
+	}
+}
+
+func (sctx *serveCtx) registerTrace() {
+	reqf := func(w http.ResponseWriter, r *http.Request) { trace.Render(w, r, true) }
+	sctx.registerUserHandler("/debug/requests", http.HandlerFunc(reqf))
+	evf := func(w http.ResponseWriter, r *http.Request) { trace.RenderEvents(w, r, true) }
+	sctx.registerUserHandler("/debug/events", http.HandlerFunc(evf))
+}