diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go b/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
index c39702e..d02a7ee 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/balancer.go
@@ -12,24 +12,45 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package balancer implements client balancer.
 package balancer
 
 import (
-	"fmt"
 	"strconv"
 	"sync"
 	"time"
 
+	"go.etcd.io/etcd/clientv3/balancer/connectivity"
 	"go.etcd.io/etcd/clientv3/balancer/picker"
 
 	"go.uber.org/zap"
 	"google.golang.org/grpc/balancer"
-	"google.golang.org/grpc/connectivity"
+	grpcconnectivity "google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/resolver"
 	_ "google.golang.org/grpc/resolver/dns"         // register DNS resolver
 	_ "google.golang.org/grpc/resolver/passthrough" // register passthrough resolver
 )
 
+// Config defines balancer configurations.
+type Config struct {
+	// Policy configures balancer policy.
+	Policy picker.Policy
+
+	// Picker implements gRPC picker.
+	// Leave empty if "Policy" field is not custom.
+	// TODO: currently custom policy is not supported.
+	// Picker picker.Picker
+
+	// Name defines an additional name for balancer.
+	// Useful for balancer testing to avoid register conflicts.
+	// If empty, defaults to policy name.
+	Name string
+
+	// Logger configures balancer logging.
+	// If nil, logs are discarded.
+	Logger *zap.Logger
+}
+
 // RegisterBuilder creates and registers a builder. Since this function calls balancer.Register, it
 // must be invoked at initialization time.
 func RegisterBuilder(cfg Config) {
@@ -59,16 +80,13 @@
 
 		addrToSc: make(map[resolver.Address]balancer.SubConn),
 		scToAddr: make(map[balancer.SubConn]resolver.Address),
-		scToSt:   make(map[balancer.SubConn]connectivity.State),
+		scToSt:   make(map[balancer.SubConn]grpcconnectivity.State),
 
-		currentConn: nil,
-		csEvltr:     &connectivityStateEvaluator{},
+		currentConn:          nil,
+		connectivityRecorder: connectivity.New(b.cfg.Logger),
 
 		// initialize picker always returns "ErrNoSubConnAvailable"
-		Picker: picker.NewErr(balancer.ErrNoSubConnAvailable),
-	}
-	if bb.lg == nil {
-		bb.lg = zap.NewNop()
+		picker: picker.NewErr(balancer.ErrNoSubConnAvailable),
 	}
 
 	// TODO: support multiple connections
@@ -112,13 +130,12 @@
 
 	addrToSc map[resolver.Address]balancer.SubConn
 	scToAddr map[balancer.SubConn]resolver.Address
-	scToSt   map[balancer.SubConn]connectivity.State
+	scToSt   map[balancer.SubConn]grpcconnectivity.State
 
-	currentConn  balancer.ClientConn
-	currentState connectivity.State
-	csEvltr      *connectivityStateEvaluator
+	currentConn          balancer.ClientConn
+	connectivityRecorder connectivity.Recorder
 
-	picker.Picker
+	picker picker.Picker
 }
 
 // HandleResolvedAddrs implements "grpc/balancer.Balancer" interface.
@@ -128,7 +145,11 @@
 		bb.lg.Warn("HandleResolvedAddrs called with error", zap.String("balancer-id", bb.id), zap.Error(err))
 		return
 	}
-	bb.lg.Info("resolved", zap.String("balancer-id", bb.id), zap.Strings("addresses", addrsToStrings(addrs)))
+	bb.lg.Info("resolved",
+		zap.String("picker", bb.picker.String()),
+		zap.String("balancer-id", bb.id),
+		zap.Strings("addresses", addrsToStrings(addrs)),
+	)
 
 	bb.mu.Lock()
 	defer bb.mu.Unlock()
@@ -139,12 +160,13 @@
 		if _, ok := bb.addrToSc[addr]; !ok {
 			sc, err := bb.currentConn.NewSubConn([]resolver.Address{addr}, balancer.NewSubConnOptions{})
 			if err != nil {
-				bb.lg.Warn("NewSubConn failed", zap.String("balancer-id", bb.id), zap.Error(err), zap.String("address", addr.Addr))
+				bb.lg.Warn("NewSubConn failed", zap.String("picker", bb.picker.String()), zap.String("balancer-id", bb.id), zap.Error(err), zap.String("address", addr.Addr))
 				continue
 			}
+			bb.lg.Info("created subconn", zap.String("address", addr.Addr))
 			bb.addrToSc[addr] = sc
 			bb.scToAddr[sc] = addr
-			bb.scToSt[sc] = connectivity.Idle
+			bb.scToSt[sc] = grpcconnectivity.Idle
 			sc.Connect()
 		}
 	}
@@ -157,6 +179,7 @@
 
 			bb.lg.Info(
 				"removed subconn",
+				zap.String("picker", bb.picker.String()),
 				zap.String("balancer-id", bb.id),
 				zap.String("address", addr.Addr),
 				zap.String("subconn", scToString(sc)),
@@ -171,7 +194,7 @@
 }
 
 // HandleSubConnStateChange implements "grpc/balancer.Balancer" interface.
-func (bb *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+func (bb *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s grpcconnectivity.State) {
 	bb.mu.Lock()
 	defer bb.mu.Unlock()
 
@@ -179,8 +202,10 @@
 	if !ok {
 		bb.lg.Warn(
 			"state change for an unknown subconn",
+			zap.String("picker", bb.picker.String()),
 			zap.String("balancer-id", bb.id),
 			zap.String("subconn", scToString(sc)),
+			zap.Int("subconn-size", len(bb.scToAddr)),
 			zap.String("state", s.String()),
 		)
 		return
@@ -188,9 +213,11 @@
 
 	bb.lg.Info(
 		"state changed",
+		zap.String("picker", bb.picker.String()),
 		zap.String("balancer-id", bb.id),
-		zap.Bool("connected", s == connectivity.Ready),
+		zap.Bool("connected", s == grpcconnectivity.Ready),
 		zap.String("subconn", scToString(sc)),
+		zap.Int("subconn-size", len(bb.scToAddr)),
 		zap.String("address", bb.scToAddr[sc].Addr),
 		zap.String("old-state", old.String()),
 		zap.String("new-state", s.String()),
@@ -198,68 +225,63 @@
 
 	bb.scToSt[sc] = s
 	switch s {
-	case connectivity.Idle:
+	case grpcconnectivity.Idle:
 		sc.Connect()
-	case connectivity.Shutdown:
+	case grpcconnectivity.Shutdown:
 		// When an address was removed by resolver, b called RemoveSubConn but
 		// kept the sc's state in scToSt. Remove state for this sc here.
 		delete(bb.scToAddr, sc)
 		delete(bb.scToSt, sc)
 	}
 
-	oldAggrState := bb.currentState
-	bb.currentState = bb.csEvltr.recordTransition(old, s)
+	oldAggrState := bb.connectivityRecorder.GetCurrentState()
+	bb.connectivityRecorder.RecordTransition(old, s)
 
-	// Regenerate picker when one of the following happens:
+	// Update balancer picker when one of the following happens:
 	//  - this sc became ready from not-ready
 	//  - this sc became not-ready from ready
 	//  - the aggregated state of balancer became TransientFailure from non-TransientFailure
 	//  - the aggregated state of balancer became non-TransientFailure from TransientFailure
-	if (s == connectivity.Ready) != (old == connectivity.Ready) ||
-		(bb.currentState == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
-		bb.regeneratePicker()
+	if (s == grpcconnectivity.Ready) != (old == grpcconnectivity.Ready) ||
+		(bb.connectivityRecorder.GetCurrentState() == grpcconnectivity.TransientFailure) != (oldAggrState == grpcconnectivity.TransientFailure) {
+		bb.updatePicker()
 	}
 
-	bb.currentConn.UpdateBalancerState(bb.currentState, bb.Picker)
+	bb.currentConn.UpdateBalancerState(bb.connectivityRecorder.GetCurrentState(), bb.picker)
 }
 
-func (bb *baseBalancer) regeneratePicker() {
-	if bb.currentState == connectivity.TransientFailure {
+func (bb *baseBalancer) updatePicker() {
+	if bb.connectivityRecorder.GetCurrentState() == grpcconnectivity.TransientFailure {
+		bb.picker = picker.NewErr(balancer.ErrTransientFailure)
 		bb.lg.Info(
-			"generated transient error picker",
+			"updated picker to transient error picker",
+			zap.String("picker", bb.picker.String()),
 			zap.String("balancer-id", bb.id),
 			zap.String("policy", bb.policy.String()),
 		)
-		bb.Picker = picker.NewErr(balancer.ErrTransientFailure)
 		return
 	}
 
 	// only pass ready subconns to picker
-	scs := make([]balancer.SubConn, 0)
-	addrToSc := make(map[resolver.Address]balancer.SubConn)
 	scToAddr := make(map[balancer.SubConn]resolver.Address)
 	for addr, sc := range bb.addrToSc {
-		if st, ok := bb.scToSt[sc]; ok && st == connectivity.Ready {
-			scs = append(scs, sc)
-			addrToSc[addr] = sc
+		if st, ok := bb.scToSt[sc]; ok && st == grpcconnectivity.Ready {
 			scToAddr[sc] = addr
 		}
 	}
 
-	switch bb.policy {
-	case picker.RoundrobinBalanced:
-		bb.Picker = picker.NewRoundrobinBalanced(bb.lg, scs, addrToSc, scToAddr)
-
-	default:
-		panic(fmt.Errorf("invalid balancer picker policy (%d)", bb.policy))
-	}
-
+	bb.picker = picker.New(picker.Config{
+		Policy:                   bb.policy,
+		Logger:                   bb.lg,
+		SubConnToResolverAddress: scToAddr,
+	})
 	bb.lg.Info(
-		"generated picker",
+		"updated picker",
+		zap.String("picker", bb.picker.String()),
 		zap.String("balancer-id", bb.id),
 		zap.String("policy", bb.policy.String()),
-		zap.Strings("subconn-ready", scsToStrings(addrToSc)),
-		zap.Int("subconn-size", len(addrToSc)),
+		zap.Strings("subconn-ready", scsToStrings(scToAddr)),
+		zap.Int("subconn-size", len(scToAddr)),
 	)
 }
 
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/config.go b/vendor/go.etcd.io/etcd/clientv3/balancer/config.go
deleted file mode 100644
index 0339a84..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/config.go
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright 2018 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 balancer
-
-import (
-	"go.etcd.io/etcd/clientv3/balancer/picker"
-
-	"go.uber.org/zap"
-)
-
-// Config defines balancer configurations.
-type Config struct {
-	// Policy configures balancer policy.
-	Policy picker.Policy
-
-	// Name defines an additional name for balancer.
-	// Useful for balancer testing to avoid register conflicts.
-	// If empty, defaults to policy name.
-	Name string
-
-	// Logger configures balancer logging.
-	// If nil, logs are discarded.
-	Logger *zap.Logger
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go
deleted file mode 100644
index 6cdeb3f..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity.go
+++ /dev/null
@@ -1,58 +0,0 @@
-// Copyright 2018 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 balancer
-
-import "google.golang.org/grpc/connectivity"
-
-// connectivityStateEvaluator gets updated by addrConns when their
-// states transition, based on which it evaluates the state of
-// ClientConn.
-type connectivityStateEvaluator struct {
-	numReady            uint64 // Number of addrConns in ready state.
-	numConnecting       uint64 // Number of addrConns in connecting state.
-	numTransientFailure uint64 // Number of addrConns in transientFailure.
-}
-
-// recordTransition records state change happening in every subConn and based on
-// that it evaluates what aggregated state should be.
-// It can only transition between Ready, Connecting and TransientFailure. Other states,
-// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
-// before any subConn is created ClientConn is in idle state. In the end when ClientConn
-// closes it is in Shutdown state.
-//
-// recordTransition should only be called synchronously from the same goroutine.
-func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
-	// Update counters.
-	for idx, state := range []connectivity.State{oldState, newState} {
-		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
-		switch state {
-		case connectivity.Ready:
-			cse.numReady += updateVal
-		case connectivity.Connecting:
-			cse.numConnecting += updateVal
-		case connectivity.TransientFailure:
-			cse.numTransientFailure += updateVal
-		}
-	}
-
-	// Evaluate.
-	if cse.numReady > 0 {
-		return connectivity.Ready
-	}
-	if cse.numConnecting > 0 {
-		return connectivity.Connecting
-	}
-	return connectivity.TransientFailure
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
new file mode 100644
index 0000000..4c4ad36
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
@@ -0,0 +1,93 @@
+// Copyright 2019 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 connectivity implements client connectivity operations.
+package connectivity
+
+import (
+	"sync"
+
+	"go.uber.org/zap"
+	"google.golang.org/grpc/connectivity"
+)
+
+// Recorder records gRPC connectivity.
+type Recorder interface {
+	GetCurrentState() connectivity.State
+	RecordTransition(oldState, newState connectivity.State)
+}
+
+// New returns a new Recorder.
+func New(lg *zap.Logger) Recorder {
+	return &recorder{lg: lg}
+}
+
+// recorder takes the connectivity states of multiple SubConns
+// and returns one aggregated connectivity state.
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+type recorder struct {
+	lg *zap.Logger
+
+	mu sync.RWMutex
+
+	cur connectivity.State
+
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+func (rc *recorder) GetCurrentState() (state connectivity.State) {
+	rc.mu.RLock()
+	defer rc.mu.RUnlock()
+	return rc.cur
+}
+
+// RecordTransition records state change happening in subConn and based on that
+// it evaluates what aggregated state should be.
+//
+//  - If at least one SubConn in Ready, the aggregated state is Ready;
+//  - Else if at least one SubConn in Connecting, the aggregated state is Connecting;
+//  - Else the aggregated state is TransientFailure.
+//
+// Idle and Shutdown are not considered.
+//
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+func (rc *recorder) RecordTransition(oldState, newState connectivity.State) {
+	rc.mu.Lock()
+	defer rc.mu.Unlock()
+
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			rc.numReady += updateVal
+		case connectivity.Connecting:
+			rc.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			rc.numTransientFailure += updateVal
+		default:
+			rc.lg.Warn("connectivity recorder received unknown state", zap.String("connectivity-state", state.String()))
+		}
+	}
+
+	switch { // must be exclusive, no overlap
+	case rc.numReady > 0:
+		rc.cur = connectivity.Ready
+	case rc.numConnecting > 0:
+		rc.cur = connectivity.Connecting
+	default:
+		rc.cur = connectivity.TransientFailure
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go b/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go
deleted file mode 100644
index 45af5e9..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/doc.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2018 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 balancer implements client balancer.
-package balancer
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go b/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go
deleted file mode 100644
index 2153767..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/grpc1.7-health.go
+++ /dev/null
@@ -1,657 +0,0 @@
-// Copyright 2018 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 balancer
-
-import (
-	"context"
-	"errors"
-	"io/ioutil"
-	"net/url"
-	"strings"
-	"sync"
-	"time"
-
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/grpclog"
-	healthpb "google.golang.org/grpc/health/grpc_health_v1"
-	"google.golang.org/grpc/status"
-)
-
-// TODO: replace with something better
-var lg = grpclog.NewLoggerV2(ioutil.Discard, ioutil.Discard, ioutil.Discard)
-
-const (
-	minHealthRetryDuration = 3 * time.Second
-	unknownService         = "unknown service grpc.health.v1.Health"
-)
-
-// ErrNoAddrAvailable is returned by Get() when the balancer does not have
-// any active connection to endpoints at the time.
-// This error is returned only when opts.BlockingWait is true.
-var ErrNoAddrAvailable = status.Error(codes.Unavailable, "there is no address available")
-
-type NotifyMsg int
-
-const (
-	NotifyReset NotifyMsg = iota
-	NotifyNext
-)
-
-// GRPC17Health does the bare minimum to expose multiple eps
-// to the grpc reconnection code path
-type GRPC17Health struct {
-	// addrs are the client's endpoint addresses for grpc
-	addrs []grpc.Address
-
-	// eps holds the raw endpoints from the client
-	eps []string
-
-	// notifyCh notifies grpc of the set of addresses for connecting
-	notifyCh chan []grpc.Address
-
-	// readyc closes once the first connection is up
-	readyc    chan struct{}
-	readyOnce sync.Once
-
-	// healthCheck checks an endpoint's health.
-	healthCheck        func(ep string) (bool, error)
-	healthCheckTimeout time.Duration
-
-	unhealthyMu        sync.RWMutex
-	unhealthyHostPorts map[string]time.Time
-
-	// mu protects all fields below.
-	mu sync.RWMutex
-
-	// upc closes when pinAddr transitions from empty to non-empty or the balancer closes.
-	upc chan struct{}
-
-	// downc closes when grpc calls down() on pinAddr
-	downc chan struct{}
-
-	// stopc is closed to signal updateNotifyLoop should stop.
-	stopc    chan struct{}
-	stopOnce sync.Once
-	wg       sync.WaitGroup
-
-	// donec closes when all goroutines are exited
-	donec chan struct{}
-
-	// updateAddrsC notifies updateNotifyLoop to update addrs.
-	updateAddrsC chan NotifyMsg
-
-	// grpc issues TLS cert checks using the string passed into dial so
-	// that string must be the host. To recover the full scheme://host URL,
-	// have a map from hosts to the original endpoint.
-	hostPort2ep map[string]string
-
-	// pinAddr is the currently pinned address; set to the empty string on
-	// initialization and shutdown.
-	pinAddr string
-
-	closed bool
-}
-
-// DialFunc defines gRPC dial function.
-type DialFunc func(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error)
-
-// NewGRPC17Health returns a new health balancer with gRPC v1.7.
-func NewGRPC17Health(
-	eps []string,
-	timeout time.Duration,
-	dialFunc DialFunc,
-) *GRPC17Health {
-	notifyCh := make(chan []grpc.Address)
-	addrs := eps2addrs(eps)
-	hb := &GRPC17Health{
-		addrs:              addrs,
-		eps:                eps,
-		notifyCh:           notifyCh,
-		readyc:             make(chan struct{}),
-		healthCheck:        func(ep string) (bool, error) { return grpcHealthCheck(ep, dialFunc) },
-		unhealthyHostPorts: make(map[string]time.Time),
-		upc:                make(chan struct{}),
-		stopc:              make(chan struct{}),
-		downc:              make(chan struct{}),
-		donec:              make(chan struct{}),
-		updateAddrsC:       make(chan NotifyMsg),
-		hostPort2ep:        getHostPort2ep(eps),
-	}
-	if timeout < minHealthRetryDuration {
-		timeout = minHealthRetryDuration
-	}
-	hb.healthCheckTimeout = timeout
-
-	close(hb.downc)
-	go hb.updateNotifyLoop()
-	hb.wg.Add(1)
-	go func() {
-		defer hb.wg.Done()
-		hb.updateUnhealthy()
-	}()
-	return hb
-}
-
-func (b *GRPC17Health) Start(target string, config grpc.BalancerConfig) error { return nil }
-
-func (b *GRPC17Health) ConnectNotify() <-chan struct{} {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.upc
-}
-
-func (b *GRPC17Health) UpdateAddrsC() chan NotifyMsg { return b.updateAddrsC }
-func (b *GRPC17Health) StopC() chan struct{}         { return b.stopc }
-
-func (b *GRPC17Health) Ready() <-chan struct{} { return b.readyc }
-
-func (b *GRPC17Health) Endpoint(hostPort string) string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.hostPort2ep[hostPort]
-}
-
-func (b *GRPC17Health) Pinned() string {
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-	return b.pinAddr
-}
-
-func (b *GRPC17Health) HostPortError(hostPort string, err error) {
-	if b.Endpoint(hostPort) == "" {
-		lg.Infof("clientv3/balancer: %q is stale (skip marking as unhealthy on %q)", hostPort, err.Error())
-		return
-	}
-
-	b.unhealthyMu.Lock()
-	b.unhealthyHostPorts[hostPort] = time.Now()
-	b.unhealthyMu.Unlock()
-	lg.Infof("clientv3/balancer: %q is marked unhealthy (%q)", hostPort, err.Error())
-}
-
-func (b *GRPC17Health) removeUnhealthy(hostPort, msg string) {
-	if b.Endpoint(hostPort) == "" {
-		lg.Infof("clientv3/balancer: %q was not in unhealthy (%q)", hostPort, msg)
-		return
-	}
-
-	b.unhealthyMu.Lock()
-	delete(b.unhealthyHostPorts, hostPort)
-	b.unhealthyMu.Unlock()
-	lg.Infof("clientv3/balancer: %q is removed from unhealthy (%q)", hostPort, msg)
-}
-
-func (b *GRPC17Health) countUnhealthy() (count int) {
-	b.unhealthyMu.RLock()
-	count = len(b.unhealthyHostPorts)
-	b.unhealthyMu.RUnlock()
-	return count
-}
-
-func (b *GRPC17Health) isUnhealthy(hostPort string) (unhealthy bool) {
-	b.unhealthyMu.RLock()
-	_, unhealthy = b.unhealthyHostPorts[hostPort]
-	b.unhealthyMu.RUnlock()
-	return unhealthy
-}
-
-func (b *GRPC17Health) cleanupUnhealthy() {
-	b.unhealthyMu.Lock()
-	for k, v := range b.unhealthyHostPorts {
-		if time.Since(v) > b.healthCheckTimeout {
-			delete(b.unhealthyHostPorts, k)
-			lg.Infof("clientv3/balancer: removed %q from unhealthy after %v", k, b.healthCheckTimeout)
-		}
-	}
-	b.unhealthyMu.Unlock()
-}
-
-func (b *GRPC17Health) liveAddrs() ([]grpc.Address, map[string]struct{}) {
-	unhealthyCnt := b.countUnhealthy()
-
-	b.mu.RLock()
-	defer b.mu.RUnlock()
-
-	hbAddrs := b.addrs
-	if len(b.addrs) == 1 || unhealthyCnt == 0 || unhealthyCnt == len(b.addrs) {
-		liveHostPorts := make(map[string]struct{}, len(b.hostPort2ep))
-		for k := range b.hostPort2ep {
-			liveHostPorts[k] = struct{}{}
-		}
-		return hbAddrs, liveHostPorts
-	}
-
-	addrs := make([]grpc.Address, 0, len(b.addrs)-unhealthyCnt)
-	liveHostPorts := make(map[string]struct{}, len(addrs))
-	for _, addr := range b.addrs {
-		if !b.isUnhealthy(addr.Addr) {
-			addrs = append(addrs, addr)
-			liveHostPorts[addr.Addr] = struct{}{}
-		}
-	}
-	return addrs, liveHostPorts
-}
-
-func (b *GRPC17Health) updateUnhealthy() {
-	for {
-		select {
-		case <-time.After(b.healthCheckTimeout):
-			b.cleanupUnhealthy()
-			pinned := b.Pinned()
-			if pinned == "" || b.isUnhealthy(pinned) {
-				select {
-				case b.updateAddrsC <- NotifyNext:
-				case <-b.stopc:
-					return
-				}
-			}
-		case <-b.stopc:
-			return
-		}
-	}
-}
-
-// NeedUpdate returns true if all connections are down or
-// addresses do not include current pinned address.
-func (b *GRPC17Health) NeedUpdate() bool {
-	// updating notifyCh can trigger new connections,
-	// need update addrs if all connections are down
-	// or addrs does not include pinAddr.
-	b.mu.RLock()
-	update := !hasAddr(b.addrs, b.pinAddr)
-	b.mu.RUnlock()
-	return update
-}
-
-func (b *GRPC17Health) UpdateAddrs(eps ...string) {
-	np := getHostPort2ep(eps)
-
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	match := len(np) == len(b.hostPort2ep)
-	if match {
-		for k, v := range np {
-			if b.hostPort2ep[k] != v {
-				match = false
-				break
-			}
-		}
-	}
-	if match {
-		// same endpoints, so no need to update address
-		return
-	}
-
-	b.hostPort2ep = np
-	b.addrs, b.eps = eps2addrs(eps), eps
-
-	b.unhealthyMu.Lock()
-	b.unhealthyHostPorts = make(map[string]time.Time)
-	b.unhealthyMu.Unlock()
-}
-
-func (b *GRPC17Health) Next() {
-	b.mu.RLock()
-	downc := b.downc
-	b.mu.RUnlock()
-	select {
-	case b.updateAddrsC <- NotifyNext:
-	case <-b.stopc:
-	}
-	// wait until disconnect so new RPCs are not issued on old connection
-	select {
-	case <-downc:
-	case <-b.stopc:
-	}
-}
-
-func (b *GRPC17Health) updateNotifyLoop() {
-	defer close(b.donec)
-
-	for {
-		b.mu.RLock()
-		upc, downc, addr := b.upc, b.downc, b.pinAddr
-		b.mu.RUnlock()
-		// downc or upc should be closed
-		select {
-		case <-downc:
-			downc = nil
-		default:
-		}
-		select {
-		case <-upc:
-			upc = nil
-		default:
-		}
-		switch {
-		case downc == nil && upc == nil:
-			// stale
-			select {
-			case <-b.stopc:
-				return
-			default:
-			}
-		case downc == nil:
-			b.notifyAddrs(NotifyReset)
-			select {
-			case <-upc:
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		case upc == nil:
-			select {
-			// close connections that are not the pinned address
-			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
-			case <-downc:
-			case <-b.stopc:
-				return
-			}
-			select {
-			case <-downc:
-				b.notifyAddrs(NotifyReset)
-			case msg := <-b.updateAddrsC:
-				b.notifyAddrs(msg)
-			case <-b.stopc:
-				return
-			}
-		}
-	}
-}
-
-func (b *GRPC17Health) notifyAddrs(msg NotifyMsg) {
-	if msg == NotifyNext {
-		select {
-		case b.notifyCh <- []grpc.Address{}:
-		case <-b.stopc:
-			return
-		}
-	}
-	b.mu.RLock()
-	pinAddr := b.pinAddr
-	downc := b.downc
-	b.mu.RUnlock()
-	addrs, hostPorts := b.liveAddrs()
-
-	var waitDown bool
-	if pinAddr != "" {
-		_, ok := hostPorts[pinAddr]
-		waitDown = !ok
-	}
-
-	select {
-	case b.notifyCh <- addrs:
-		if waitDown {
-			select {
-			case <-downc:
-			case <-b.stopc:
-			}
-		}
-	case <-b.stopc:
-	}
-}
-
-func (b *GRPC17Health) Up(addr grpc.Address) func(error) {
-	if !b.mayPin(addr) {
-		return func(err error) {}
-	}
-
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	// gRPC might call Up after it called Close. We add this check
-	// to "fix" it up at application layer. Otherwise, will panic
-	// if b.upc is already closed.
-	if b.closed {
-		return func(err error) {}
-	}
-
-	// gRPC might call Up on a stale address.
-	// Prevent updating pinAddr with a stale address.
-	if !hasAddr(b.addrs, addr.Addr) {
-		return func(err error) {}
-	}
-
-	if b.pinAddr != "" {
-		lg.Infof("clientv3/balancer: %q is up but not pinned (already pinned %q)", addr.Addr, b.pinAddr)
-		return func(err error) {}
-	}
-
-	// notify waiting Get()s and pin first connected address
-	close(b.upc)
-	b.downc = make(chan struct{})
-	b.pinAddr = addr.Addr
-	lg.Infof("clientv3/balancer: pin %q", addr.Addr)
-
-	// notify client that a connection is up
-	b.readyOnce.Do(func() { close(b.readyc) })
-
-	return func(err error) {
-		// If connected to a black hole endpoint or a killed server, the gRPC ping
-		// timeout will induce a network I/O error, and retrying until success;
-		// finding healthy endpoint on retry could take several timeouts and redials.
-		// To avoid wasting retries, gray-list unhealthy endpoints.
-		b.HostPortError(addr.Addr, err)
-
-		b.mu.Lock()
-		b.upc = make(chan struct{})
-		close(b.downc)
-		b.pinAddr = ""
-		b.mu.Unlock()
-		lg.Infof("clientv3/balancer: unpin %q (%q)", addr.Addr, err.Error())
-	}
-}
-
-func (b *GRPC17Health) mayPin(addr grpc.Address) bool {
-	if b.Endpoint(addr.Addr) == "" { // stale host:port
-		return false
-	}
-
-	b.unhealthyMu.RLock()
-	unhealthyCnt := len(b.unhealthyHostPorts)
-	failedTime, bad := b.unhealthyHostPorts[addr.Addr]
-	b.unhealthyMu.RUnlock()
-
-	b.mu.RLock()
-	skip := len(b.addrs) == 1 || unhealthyCnt == 0 || len(b.addrs) == unhealthyCnt
-	b.mu.RUnlock()
-	if skip || !bad {
-		return true
-	}
-
-	// prevent isolated member's endpoint from being infinitely retried, as follows:
-	//   1. keepalive pings detects GoAway with http2.ErrCodeEnhanceYourCalm
-	//   2. balancer 'Up' unpins with grpc: failed with network I/O error
-	//   3. grpc-healthcheck still SERVING, thus retry to pin
-	// instead, return before grpc-healthcheck if failed within healthcheck timeout
-	if elapsed := time.Since(failedTime); elapsed < b.healthCheckTimeout {
-		lg.Infof("clientv3/balancer: %q is up but not pinned (failed %v ago, require minimum %v after failure)", addr.Addr, elapsed, b.healthCheckTimeout)
-		return false
-	}
-
-	if ok, _ := b.healthCheck(addr.Addr); ok {
-		b.removeUnhealthy(addr.Addr, "health check success")
-		return true
-	}
-
-	b.HostPortError(addr.Addr, errors.New("health check failed"))
-	return false
-}
-
-func (b *GRPC17Health) Get(ctx context.Context, opts grpc.BalancerGetOptions) (grpc.Address, func(), error) {
-	var (
-		addr   string
-		closed bool
-	)
-
-	// If opts.BlockingWait is false (for fail-fast RPCs), it should return
-	// an address it has notified via Notify immediately instead of blocking.
-	if !opts.BlockingWait {
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr == "" {
-			return grpc.Address{Addr: ""}, nil, ErrNoAddrAvailable
-		}
-		return grpc.Address{Addr: addr}, func() {}, nil
-	}
-
-	for {
-		b.mu.RLock()
-		ch := b.upc
-		b.mu.RUnlock()
-		select {
-		case <-ch:
-		case <-b.donec:
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		case <-ctx.Done():
-			return grpc.Address{Addr: ""}, nil, ctx.Err()
-		}
-		b.mu.RLock()
-		closed = b.closed
-		addr = b.pinAddr
-		b.mu.RUnlock()
-		// Close() which sets b.closed = true can be called before Get(), Get() must exit if balancer is closed.
-		if closed {
-			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
-		}
-		if addr != "" {
-			break
-		}
-	}
-	return grpc.Address{Addr: addr}, func() {}, nil
-}
-
-func (b *GRPC17Health) Notify() <-chan []grpc.Address { return b.notifyCh }
-
-func (b *GRPC17Health) Close() error {
-	b.mu.Lock()
-	// In case gRPC calls close twice. TODO: remove the checking
-	// when we are sure that gRPC wont call close twice.
-	if b.closed {
-		b.mu.Unlock()
-		<-b.donec
-		return nil
-	}
-	b.closed = true
-	b.stopOnce.Do(func() { close(b.stopc) })
-	b.pinAddr = ""
-
-	// In the case of following scenario:
-	//	1. upc is not closed; no pinned address
-	// 	2. client issues an RPC, calling invoke(), which calls Get(), enters for loop, blocks
-	// 	3. client.conn.Close() calls balancer.Close(); closed = true
-	// 	4. for loop in Get() never exits since ctx is the context passed in by the client and may not be canceled
-	// we must close upc so Get() exits from blocking on upc
-	select {
-	case <-b.upc:
-	default:
-		// terminate all waiting Get()s
-		close(b.upc)
-	}
-
-	b.mu.Unlock()
-	b.wg.Wait()
-
-	// wait for updateNotifyLoop to finish
-	<-b.donec
-	close(b.notifyCh)
-
-	return nil
-}
-
-func grpcHealthCheck(ep string, dialFunc func(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error)) (bool, error) {
-	conn, err := dialFunc(ep)
-	if err != nil {
-		return false, err
-	}
-	defer conn.Close()
-	cli := healthpb.NewHealthClient(conn)
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-	resp, err := cli.Check(ctx, &healthpb.HealthCheckRequest{})
-	cancel()
-	if err != nil {
-		if s, ok := status.FromError(err); ok && s.Code() == codes.Unavailable {
-			if s.Message() == unknownService { // etcd < v3.3.0
-				return true, nil
-			}
-		}
-		return false, err
-	}
-	return resp.Status == healthpb.HealthCheckResponse_SERVING, nil
-}
-
-func hasAddr(addrs []grpc.Address, targetAddr string) bool {
-	for _, addr := range addrs {
-		if targetAddr == addr.Addr {
-			return true
-		}
-	}
-	return false
-}
-
-func getHost(ep string) string {
-	url, uerr := url.Parse(ep)
-	if uerr != nil || !strings.Contains(ep, "://") {
-		return ep
-	}
-	return url.Host
-}
-
-func eps2addrs(eps []string) []grpc.Address {
-	addrs := make([]grpc.Address, len(eps))
-	for i := range eps {
-		addrs[i].Addr = getHost(eps[i])
-	}
-	return addrs
-}
-
-func getHostPort2ep(eps []string) map[string]string {
-	hm := make(map[string]string, len(eps))
-	for i := range eps {
-		_, host, _ := parseEndpoint(eps[i])
-		hm[host] = eps[i]
-	}
-	return hm
-}
-
-func parseEndpoint(endpoint string) (proto string, host string, scheme string) {
-	proto = "tcp"
-	host = endpoint
-	url, uerr := url.Parse(endpoint)
-	if uerr != nil || !strings.Contains(endpoint, "://") {
-		return proto, host, scheme
-	}
-	scheme = url.Scheme
-
-	// strip scheme:// prefix since grpc dials by host
-	host = url.Host
-	switch url.Scheme {
-	case "http", "https":
-	case "unix", "unixs":
-		proto = "unix"
-		host = url.Host + url.Path
-	default:
-		proto, host = "", ""
-	}
-	return proto, host, scheme
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
index c70ce15..9e04378 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/err.go
@@ -22,13 +22,18 @@
 
 // NewErr returns a picker that always returns err on "Pick".
 func NewErr(err error) Picker {
-	return &errPicker{err: err}
+	return &errPicker{p: Error, err: err}
 }
 
 type errPicker struct {
+	p   Policy
 	err error
 }
 
-func (p *errPicker) Pick(context.Context, balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
-	return nil, nil, p.err
+func (ep *errPicker) String() string {
+	return ep.p.String()
+}
+
+func (ep *errPicker) Pick(context.Context, balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	return nil, nil, ep.err
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
index 7ea761b..bd1a5d2 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker.go
@@ -15,10 +15,77 @@
 package picker
 
 import (
+	"fmt"
+
+	"go.uber.org/zap"
 	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/resolver"
 )
 
 // Picker defines balancer Picker methods.
 type Picker interface {
 	balancer.Picker
+	String() string
+}
+
+// Config defines picker configuration.
+type Config struct {
+	// Policy specifies etcd clientv3's built in balancer policy.
+	Policy Policy
+
+	// Logger defines picker logging object.
+	Logger *zap.Logger
+
+	// SubConnToResolverAddress maps each gRPC sub-connection to an address.
+	// Basically, it is a list of addresses that the Picker can pick from.
+	SubConnToResolverAddress map[balancer.SubConn]resolver.Address
+}
+
+// Policy defines balancer picker policy.
+type Policy uint8
+
+const (
+	// Error is error picker policy.
+	Error Policy = iota
+
+	// RoundrobinBalanced balances loads over multiple endpoints
+	// and implements failover in roundrobin fashion.
+	RoundrobinBalanced
+
+	// Custom defines custom balancer picker.
+	// TODO: custom picker is not supported yet.
+	Custom
+)
+
+func (p Policy) String() string {
+	switch p {
+	case Error:
+		return "picker-error"
+
+	case RoundrobinBalanced:
+		return "picker-roundrobin-balanced"
+
+	case Custom:
+		panic("'custom' picker policy is not supported yet")
+
+	default:
+		panic(fmt.Errorf("invalid balancer picker policy (%d)", p))
+	}
+}
+
+// New creates a new Picker.
+func New(cfg Config) Picker {
+	switch cfg.Policy {
+	case Error:
+		panic("'error' picker policy is not supported here; use 'picker.NewErr'")
+
+	case RoundrobinBalanced:
+		return newRoundrobinBalanced(cfg)
+
+	case Custom:
+		panic("'custom' picker policy is not supported yet")
+
+	default:
+		panic(fmt.Errorf("invalid balancer picker policy (%d)", cfg.Policy))
+	}
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go
deleted file mode 100644
index 7bca39c..0000000
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/picker_policy.go
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright 2018 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 picker
-
-import "fmt"
-
-// Policy defines balancer picker policy.
-type Policy uint8
-
-const (
-	// TODO: custom picker is not supported yet.
-	// custom defines custom balancer picker.
-	custom Policy = iota
-
-	// RoundrobinBalanced balance loads over multiple endpoints
-	// and implements failover in roundrobin fashion.
-	RoundrobinBalanced Policy = iota
-
-	// TODO: only send loads to pinned address "RoundrobinFailover"
-	// just like how 3.3 client works
-	//
-	// TODO: prioritize leader
-	// TODO: health-check
-	// TODO: weighted roundrobin
-	// TODO: power of two random choice
-)
-
-func (p Policy) String() string {
-	switch p {
-	case custom:
-		panic("'custom' picker policy is not supported yet")
-	case RoundrobinBalanced:
-		return "etcd-client-roundrobin-balanced"
-	default:
-		panic(fmt.Errorf("invalid balancer picker policy (%d)", p))
-	}
-}
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
index b043d57..1b8b285 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/picker/roundrobin_balanced.go
@@ -24,32 +24,33 @@
 	"google.golang.org/grpc/resolver"
 )
 
-// NewRoundrobinBalanced returns a new roundrobin balanced picker.
-func NewRoundrobinBalanced(
-	lg *zap.Logger,
-	scs []balancer.SubConn,
-	addrToSc map[resolver.Address]balancer.SubConn,
-	scToAddr map[balancer.SubConn]resolver.Address,
-) Picker {
+// newRoundrobinBalanced returns a new roundrobin balanced picker.
+func newRoundrobinBalanced(cfg Config) Picker {
+	scs := make([]balancer.SubConn, 0, len(cfg.SubConnToResolverAddress))
+	for sc := range cfg.SubConnToResolverAddress {
+		scs = append(scs, sc)
+	}
 	return &rrBalanced{
-		lg:       lg,
+		p:        RoundrobinBalanced,
+		lg:       cfg.Logger,
 		scs:      scs,
-		addrToSc: addrToSc,
-		scToAddr: scToAddr,
+		scToAddr: cfg.SubConnToResolverAddress,
 	}
 }
 
 type rrBalanced struct {
+	p Policy
+
 	lg *zap.Logger
 
-	mu   sync.RWMutex
-	next int
-	scs  []balancer.SubConn
-
-	addrToSc map[resolver.Address]balancer.SubConn
+	mu       sync.RWMutex
+	next     int
+	scs      []balancer.SubConn
 	scToAddr map[balancer.SubConn]resolver.Address
 }
 
+func (rb *rrBalanced) String() string { return rb.p.String() }
+
 // Pick is called for every client request.
 func (rb *rrBalanced) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
 	rb.mu.RLock()
@@ -68,6 +69,7 @@
 
 	rb.lg.Debug(
 		"picked",
+		zap.String("picker", rb.p.String()),
 		zap.String("address", picked),
 		zap.Int("subconn-index", cur),
 		zap.Int("subconn-size", n),
@@ -77,6 +79,7 @@
 		// TODO: error handling?
 		fss := []zapcore.Field{
 			zap.Error(info.Err),
+			zap.String("picker", rb.p.String()),
 			zap.String("address", picked),
 			zap.Bool("success", info.Err == nil),
 			zap.Bool("bytes-sent", info.BytesSent),
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go b/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
index a11faeb..48eb875 100644
--- a/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/utils.go
@@ -29,9 +29,9 @@
 	return fmt.Sprintf("%p", sc)
 }
 
-func scsToStrings(scs map[resolver.Address]balancer.SubConn) (ss []string) {
+func scsToStrings(scs map[balancer.SubConn]resolver.Address) (ss []string) {
 	ss = make([]string, 0, len(scs))
-	for a, sc := range scs {
+	for sc, a := range scs {
 		ss = append(ss, fmt.Sprintf("%s (%s)", a.Addr, scToString(sc)))
 	}
 	sort.Strings(ss)
diff --git a/vendor/go.etcd.io/etcd/clientv3/client.go b/vendor/go.etcd.io/etcd/clientv3/client.go
index b91cbf9..d6000a8 100644
--- a/vendor/go.etcd.io/etcd/clientv3/client.go
+++ b/vendor/go.etcd.io/etcd/clientv3/client.go
@@ -16,7 +16,6 @@
 
 import (
 	"context"
-	"crypto/tls"
 	"errors"
 	"fmt"
 	"net"
@@ -30,12 +29,13 @@
 	"go.etcd.io/etcd/clientv3/balancer"
 	"go.etcd.io/etcd/clientv3/balancer/picker"
 	"go.etcd.io/etcd/clientv3/balancer/resolver/endpoint"
+	"go.etcd.io/etcd/clientv3/credentials"
 	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
 	"go.etcd.io/etcd/pkg/logutil"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/credentials"
+	grpccredentials "google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/status"
@@ -51,12 +51,17 @@
 func init() {
 	lg := zap.NewNop()
 	if os.Getenv("ETCD_CLIENT_DEBUG") != "" {
+		lcfg := logutil.DefaultZapLoggerConfig
+		lcfg.Level = zap.NewAtomicLevelAt(zap.DebugLevel)
+
 		var err error
-		lg, err = zap.NewProductionConfig().Build() // info level logging
+		lg, err = lcfg.Build() // info level logging
 		if err != nil {
 			panic(err)
 		}
 	}
+
+	// TODO: support custom balancer
 	balancer.RegisterBuilder(balancer.Config{
 		Policy: picker.RoundrobinBalanced,
 		Name:   roundRobinBalancerName,
@@ -76,7 +81,7 @@
 	conn *grpc.ClientConn
 
 	cfg           Config
-	creds         *credentials.TransportCredentials
+	creds         grpccredentials.TransportCredentials
 	resolverGroup *endpoint.ResolverGroup
 	mu            *sync.RWMutex
 
@@ -86,9 +91,8 @@
 	// Username is a user name for authentication.
 	Username string
 	// Password is a password for authentication.
-	Password string
-	// tokenCred is an instance of WithPerRPCCredentials()'s argument
-	tokenCred *authTokenCredential
+	Password        string
+	authTokenBundle credentials.Bundle
 
 	callOpts []grpc.CallOption
 
@@ -125,8 +129,12 @@
 // Close shuts down the client's etcd connections.
 func (c *Client) Close() error {
 	c.cancel()
-	c.Watcher.Close()
-	c.Lease.Close()
+	if c.Watcher != nil {
+		c.Watcher.Close()
+	}
+	if c.Lease != nil {
+		c.Lease.Close()
+	}
 	if c.resolverGroup != nil {
 		c.resolverGroup.Close()
 	}
@@ -193,24 +201,7 @@
 	}
 }
 
-type authTokenCredential struct {
-	token   string
-	tokenMu *sync.RWMutex
-}
-
-func (cred authTokenCredential) RequireTransportSecurity() bool {
-	return false
-}
-
-func (cred authTokenCredential) GetRequestMetadata(ctx context.Context, s ...string) (map[string]string, error) {
-	cred.tokenMu.RLock()
-	defer cred.tokenMu.RUnlock()
-	return map[string]string{
-		rpctypes.TokenFieldNameGRPC: cred.token,
-	}, nil
-}
-
-func (c *Client) processCreds(scheme string) (creds *credentials.TransportCredentials) {
+func (c *Client) processCreds(scheme string) (creds grpccredentials.TransportCredentials) {
 	creds = c.creds
 	switch scheme {
 	case "unix":
@@ -220,9 +211,7 @@
 		if creds != nil {
 			break
 		}
-		tlsconfig := &tls.Config{}
-		emptyCreds := credentials.NewTLS(tlsconfig)
-		creds = &emptyCreds
+		creds = credentials.NewBundle(credentials.Config{}).TransportCredentials()
 	default:
 		creds = nil
 	}
@@ -230,7 +219,7 @@
 }
 
 // dialSetupOpts gives the dial opts prior to any authentication.
-func (c *Client) dialSetupOpts(creds *credentials.TransportCredentials, dopts ...grpc.DialOption) (opts []grpc.DialOption, err error) {
+func (c *Client) dialSetupOpts(creds grpccredentials.TransportCredentials, dopts ...grpc.DialOption) (opts []grpc.DialOption, err error) {
 	if c.cfg.DialKeepAliveTime > 0 {
 		params := keepalive.ClientParameters{
 			Time:                c.cfg.DialKeepAliveTime,
@@ -255,7 +244,7 @@
 	opts = append(opts, grpc.WithDialer(f))
 
 	if creds != nil {
-		opts = append(opts, grpc.WithTransportCredentials(*creds))
+		opts = append(opts, grpc.WithTransportCredentials(creds))
 	} else {
 		opts = append(opts, grpc.WithInsecure())
 	}
@@ -289,8 +278,8 @@
 	var err error // return last error in a case of fail
 	var auth *authenticator
 
-	for i := 0; i < len(c.cfg.Endpoints); i++ {
-		ep := c.cfg.Endpoints[i]
+	eps := c.Endpoints()
+	for _, ep := range eps {
 		// use dial options without dopts to avoid reusing the client balancer
 		var dOpts []grpc.DialOption
 		_, host, _ := endpoint.ParseEndpoint(ep)
@@ -318,10 +307,7 @@
 			continue
 		}
 
-		c.tokenCred.tokenMu.Lock()
-		c.tokenCred.token = resp.Token
-		c.tokenCred.tokenMu.Unlock()
-
+		c.authTokenBundle.UpdateAuthToken(resp.Token)
 		return nil
 	}
 
@@ -338,16 +324,14 @@
 }
 
 // dial configures and dials any grpc balancer target.
-func (c *Client) dial(target string, creds *credentials.TransportCredentials, dopts ...grpc.DialOption) (*grpc.ClientConn, error) {
+func (c *Client) dial(target string, creds grpccredentials.TransportCredentials, dopts ...grpc.DialOption) (*grpc.ClientConn, error) {
 	opts, err := c.dialSetupOpts(creds, dopts...)
 	if err != nil {
 		return nil, fmt.Errorf("failed to configure dialer: %v", err)
 	}
 
 	if c.Username != "" && c.Password != "" {
-		c.tokenCred = &authTokenCredential{
-			tokenMu: &sync.RWMutex{},
-		}
+		c.authTokenBundle = credentials.NewBundle(credentials.Config{})
 
 		ctx, cancel := c.ctx, func() {}
 		if c.cfg.DialTimeout > 0 {
@@ -364,7 +348,7 @@
 				return nil, err
 			}
 		} else {
-			opts = append(opts, grpc.WithPerRPCCredentials(c.tokenCred))
+			opts = append(opts, grpc.WithPerRPCCredentials(c.authTokenBundle.PerRPCCredentials()))
 		}
 		cancel()
 	}
@@ -385,26 +369,25 @@
 	return conn, nil
 }
 
-func (c *Client) directDialCreds(ep string) *credentials.TransportCredentials {
+func (c *Client) directDialCreds(ep string) grpccredentials.TransportCredentials {
 	_, hostPort, scheme := endpoint.ParseEndpoint(ep)
 	creds := c.creds
 	if len(scheme) != 0 {
 		creds = c.processCreds(scheme)
 		if creds != nil {
-			c := *creds
-			clone := c.Clone()
+			clone := creds.Clone()
 			// Set the server name must to the endpoint hostname without port since grpc
 			// otherwise attempts to check if x509 cert is valid for the full endpoint
 			// including the scheme and port, which fails.
 			host, _ := endpoint.ParseHostPort(hostPort)
 			clone.OverrideServerName(host)
-			creds = &clone
+			creds = clone
 		}
 	}
 	return creds
 }
 
-func (c *Client) dialWithBalancerCreds(ep string) *credentials.TransportCredentials {
+func (c *Client) dialWithBalancerCreds(ep string) grpccredentials.TransportCredentials {
 	_, _, scheme := endpoint.ParseEndpoint(ep)
 	creds := c.creds
 	if len(scheme) != 0 {
@@ -424,10 +407,9 @@
 	if cfg == nil {
 		cfg = &Config{}
 	}
-	var creds *credentials.TransportCredentials
+	var creds grpccredentials.TransportCredentials
 	if cfg.TLS != nil {
-		c := credentials.NewTLS(cfg.TLS)
-		creds = &c
+		creds = credentials.NewBundle(credentials.Config{TLSConfig: cfg.TLS}).TransportCredentials()
 	}
 
 	// use a temporary skeleton client to bootstrap first connection
@@ -541,13 +523,17 @@
 
 func (c *Client) checkVersion() (err error) {
 	var wg sync.WaitGroup
-	errc := make(chan error, len(c.cfg.Endpoints))
+
+	eps := c.Endpoints()
+	errc := make(chan error, len(eps))
 	ctx, cancel := context.WithCancel(c.ctx)
 	if c.cfg.DialTimeout > 0 {
-		ctx, cancel = context.WithTimeout(ctx, c.cfg.DialTimeout)
+		cancel()
+		ctx, cancel = context.WithTimeout(c.ctx, c.cfg.DialTimeout)
 	}
-	wg.Add(len(c.cfg.Endpoints))
-	for _, ep := range c.cfg.Endpoints {
+
+	wg.Add(len(eps))
+	for _, ep := range eps {
 		// if cluster is current, any endpoint gives a recent version
 		go func(e string) {
 			defer wg.Done()
@@ -559,8 +545,15 @@
 			vs := strings.Split(resp.Version, ".")
 			maj, min := 0, 0
 			if len(vs) >= 2 {
-				maj, _ = strconv.Atoi(vs[0])
-				min, rerr = strconv.Atoi(vs[1])
+				var serr error
+				if maj, serr = strconv.Atoi(vs[0]); serr != nil {
+					errc <- serr
+					return
+				}
+				if min, serr = strconv.Atoi(vs[1]); serr != nil {
+					errc <- serr
+					return
+				}
 			}
 			if maj < 3 || (maj == 3 && min < 2) {
 				rerr = ErrOldCluster
@@ -569,7 +562,7 @@
 		}(ep)
 	}
 	// wait for success
-	for i := 0; i < len(c.cfg.Endpoints); i++ {
+	for range eps {
 		if err = <-errc; err == nil {
 			break
 		}
@@ -609,10 +602,13 @@
 	if err == nil {
 		return false
 	}
-	ev, _ := status.FromError(err)
-	// Unavailable codes mean the system will be right back.
-	// (e.g., can't connect, lost leader)
-	return ev.Code() == codes.Unavailable
+	ev, ok := status.FromError(err)
+	if ok {
+		// Unavailable codes mean the system will be right back.
+		// (e.g., can't connect, lost leader)
+		return ev.Code() == codes.Unavailable
+	}
+	return false
 }
 
 func toErr(ctx context.Context, err error) error {
@@ -632,9 +628,6 @@
 			if ctx.Err() != nil {
 				err = ctx.Err()
 			}
-		case codes.Unavailable:
-		case codes.FailedPrecondition:
-			err = grpc.ErrClientConnClosing
 		}
 	}
 	return err
@@ -654,16 +647,19 @@
 	if err == nil {
 		return false
 	}
-	// >= gRPC v1.10.x
+
+	// >= gRPC v1.23.x
 	s, ok := status.FromError(err)
 	if ok {
 		// connection is canceled or server has already closed the connection
 		return s.Code() == codes.Canceled || s.Message() == "transport is closing"
 	}
+
 	// >= gRPC v1.10.x
 	if err == context.Canceled {
 		return true
 	}
+
 	// <= gRPC v1.7.x returns 'errors.New("grpc: the client connection is closing")'
 	return strings.Contains(err.Error(), "grpc: the client connection is closing")
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
index 0135341..306470b 100644
--- a/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
+++ b/vendor/go.etcd.io/etcd/clientv3/concurrency/mutex.go
@@ -16,6 +16,7 @@
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sync"
 
@@ -23,6 +24,9 @@
 	pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
 )
 
+// ErrLocked is returned by TryLock when Mutex is already locked by another session.
+var ErrLocked = errors.New("mutex: Locked by another session")
+
 // Mutex implements the sync Locker interface with etcd
 type Mutex struct {
 	s *Session
@@ -37,9 +41,56 @@
 	return &Mutex{s, pfx + "/", "", -1, nil}
 }
 
+// TryLock locks the mutex if not already locked by another session.
+// If lock is held by another session, return immediately after attempting necessary cleanup
+// The ctx argument is used for the sending/receiving Txn RPC.
+func (m *Mutex) TryLock(ctx context.Context) error {
+	resp, err := m.tryAcquire(ctx)
+	if err != nil {
+		return err
+	}
+	// if no key on prefix / the minimum rev is key, already hold the lock
+	ownerKey := resp.Responses[1].GetResponseRange().Kvs
+	if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
+		m.hdr = resp.Header
+		return nil
+	}
+	client := m.s.Client()
+	// Cannot lock, so delete the key
+	if _, err := client.Delete(ctx, m.myKey); err != nil {
+		return err
+	}
+	m.myKey = "\x00"
+	m.myRev = -1
+	return ErrLocked
+}
+
 // Lock locks the mutex with a cancelable context. If the context is canceled
 // while trying to acquire the lock, the mutex tries to clean its stale lock entry.
 func (m *Mutex) Lock(ctx context.Context) error {
+	resp, err := m.tryAcquire(ctx)
+	if err != nil {
+		return err
+	}
+	// if no key on prefix / the minimum rev is key, already hold the lock
+	ownerKey := resp.Responses[1].GetResponseRange().Kvs
+	if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
+		m.hdr = resp.Header
+		return nil
+	}
+	client := m.s.Client()
+	// wait for deletion revisions prior to myKey
+	hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
+	// release lock key if wait failed
+	if werr != nil {
+		m.Unlock(client.Ctx())
+	} else {
+		m.hdr = hdr
+	}
+	return werr
+}
+
+func (m *Mutex) tryAcquire(ctx context.Context) (*v3.TxnResponse, error) {
 	s := m.s
 	client := m.s.Client()
 
@@ -53,28 +104,13 @@
 	getOwner := v3.OpGet(m.pfx, v3.WithFirstCreate()...)
 	resp, err := client.Txn(ctx).If(cmp).Then(put, getOwner).Else(get, getOwner).Commit()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	m.myRev = resp.Header.Revision
 	if !resp.Succeeded {
 		m.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
 	}
-	// if no key on prefix / the minimum rev is key, already hold the lock
-	ownerKey := resp.Responses[1].GetResponseRange().Kvs
-	if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
-		m.hdr = resp.Header
-		return nil
-	}
-
-	// wait for deletion revisions prior to myKey
-	hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
-	// release lock key if wait failed
-	if werr != nil {
-		m.Unlock(client.Ctx())
-	} else {
-		m.hdr = hdr
-	}
-	return werr
+	return resp, nil
 }
 
 func (m *Mutex) Unlock(ctx context.Context) error {
diff --git a/vendor/go.etcd.io/etcd/clientv3/config.go b/vendor/go.etcd.io/etcd/clientv3/config.go
index bd03768..11d447d 100644
--- a/vendor/go.etcd.io/etcd/clientv3/config.go
+++ b/vendor/go.etcd.io/etcd/clientv3/config.go
@@ -68,6 +68,8 @@
 	RejectOldCluster bool `json:"reject-old-cluster"`
 
 	// DialOptions is a list of dial options for the grpc client (e.g., for interceptors).
+	// For example, pass "grpc.WithBlock()" to block until the underlying connection is up.
+	// Without this, Dial returns immediately and connecting the server happens in background.
 	DialOptions []grpc.DialOption
 
 	// Context is the default client context; it can be used to cancel grpc dial out and
@@ -81,4 +83,6 @@
 
 	// PermitWithoutStream when set will allow client to send keepalive pings to server without any active streams(RPCs).
 	PermitWithoutStream bool `json:"permit-without-stream"`
+
+	// TODO: support custom balancer picker
 }
diff --git a/vendor/go.etcd.io/etcd/clientv3/credentials/credentials.go b/vendor/go.etcd.io/etcd/clientv3/credentials/credentials.go
new file mode 100644
index 0000000..e6fd75c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/credentials/credentials.go
@@ -0,0 +1,155 @@
+// Copyright 2019 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 credentials implements gRPC credential interface with etcd specific logic.
+// e.g., client handshake with custom authority parameter
+package credentials
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+	"sync"
+
+	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
+	grpccredentials "google.golang.org/grpc/credentials"
+)
+
+// Config defines gRPC credential configuration.
+type Config struct {
+	TLSConfig *tls.Config
+}
+
+// Bundle defines gRPC credential interface.
+type Bundle interface {
+	grpccredentials.Bundle
+	UpdateAuthToken(token string)
+}
+
+// NewBundle constructs a new gRPC credential bundle.
+func NewBundle(cfg Config) Bundle {
+	return &bundle{
+		tc: newTransportCredential(cfg.TLSConfig),
+		rc: newPerRPCCredential(),
+	}
+}
+
+// bundle implements "grpccredentials.Bundle" interface.
+type bundle struct {
+	tc *transportCredential
+	rc *perRPCCredential
+}
+
+func (b *bundle) TransportCredentials() grpccredentials.TransportCredentials {
+	return b.tc
+}
+
+func (b *bundle) PerRPCCredentials() grpccredentials.PerRPCCredentials {
+	return b.rc
+}
+
+func (b *bundle) NewWithMode(mode string) (grpccredentials.Bundle, error) {
+	// no-op
+	return nil, nil
+}
+
+// transportCredential implements "grpccredentials.TransportCredentials" interface.
+type transportCredential struct {
+	gtc grpccredentials.TransportCredentials
+}
+
+func newTransportCredential(cfg *tls.Config) *transportCredential {
+	return &transportCredential{
+		gtc: grpccredentials.NewTLS(cfg),
+	}
+}
+
+func (tc *transportCredential) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (net.Conn, grpccredentials.AuthInfo, error) {
+	// Only overwrite when authority is an IP address!
+	// Let's say, a server runs SRV records on "etcd.local" that resolves
+	// to "m1.etcd.local", and its SAN field also includes "m1.etcd.local".
+	// But what if SAN does not include its resolved IP address (e.g. 127.0.0.1)?
+	// Then, the server should only authenticate using its DNS hostname "m1.etcd.local",
+	// instead of overwriting it with its IP address.
+	// And we do not overwrite "localhost" either. Only overwrite IP addresses!
+	if isIP(authority) {
+		target := rawConn.RemoteAddr().String()
+		if authority != target {
+			// When user dials with "grpc.WithDialer", "grpc.DialContext" "cc.parsedTarget"
+			// update only happens once. This is problematic, because when TLS is enabled,
+			// retries happen through "grpc.WithDialer" with static "cc.parsedTarget" from
+			// the initial dial call.
+			// If the server authenticates by IP addresses, we want to set a new endpoint as
+			// a new authority. Otherwise
+			// "transport: authentication handshake failed: x509: certificate is valid for 127.0.0.1, 192.168.121.180, not 192.168.223.156"
+			// when the new dial target is "192.168.121.180" whose certificate host name is also "192.168.121.180"
+			// but client tries to authenticate with previously set "cc.parsedTarget" field "192.168.223.156"
+			authority = target
+		}
+	}
+	return tc.gtc.ClientHandshake(ctx, authority, rawConn)
+}
+
+// return true if given string is an IP.
+func isIP(ep string) bool {
+	return net.ParseIP(ep) != nil
+}
+
+func (tc *transportCredential) ServerHandshake(rawConn net.Conn) (net.Conn, grpccredentials.AuthInfo, error) {
+	return tc.gtc.ServerHandshake(rawConn)
+}
+
+func (tc *transportCredential) Info() grpccredentials.ProtocolInfo {
+	return tc.gtc.Info()
+}
+
+func (tc *transportCredential) Clone() grpccredentials.TransportCredentials {
+	return &transportCredential{
+		gtc: tc.gtc.Clone(),
+	}
+}
+
+func (tc *transportCredential) OverrideServerName(serverNameOverride string) error {
+	return tc.gtc.OverrideServerName(serverNameOverride)
+}
+
+// perRPCCredential implements "grpccredentials.PerRPCCredentials" interface.
+type perRPCCredential struct {
+	authToken   string
+	authTokenMu sync.RWMutex
+}
+
+func newPerRPCCredential() *perRPCCredential { return &perRPCCredential{} }
+
+func (rc *perRPCCredential) RequireTransportSecurity() bool { return false }
+
+func (rc *perRPCCredential) GetRequestMetadata(ctx context.Context, s ...string) (map[string]string, error) {
+	rc.authTokenMu.RLock()
+	authToken := rc.authToken
+	rc.authTokenMu.RUnlock()
+	return map[string]string{rpctypes.TokenFieldNameGRPC: authToken}, nil
+}
+
+func (b *bundle) UpdateAuthToken(token string) {
+	if b.rc == nil {
+		return
+	}
+	b.rc.UpdateAuthToken(token)
+}
+
+func (rc *perRPCCredential) UpdateAuthToken(token string) {
+	rc.authTokenMu.Lock()
+	rc.authToken = token
+	rc.authTokenMu.Unlock()
+}
diff --git a/vendor/go.etcd.io/etcd/clientv3/doc.go b/vendor/go.etcd.io/etcd/clientv3/doc.go
index 01a3f59..913cd28 100644
--- a/vendor/go.etcd.io/etcd/clientv3/doc.go
+++ b/vendor/go.etcd.io/etcd/clientv3/doc.go
@@ -90,7 +90,7 @@
 //		// with etcd clientv3 <= v3.3
 //		if err == context.Canceled {
 //			// grpc balancer calls 'Get' with an inflight client.Close
-//		} else if err == grpc.ErrClientConnClosing {
+//		} else if err == grpc.ErrClientConnClosing { // <= gRCP v1.7.x
 //			// grpc balancer calls 'Get' after client.Close.
 //		}
 //		// with etcd clientv3 >= v3.4