diff --git a/core/discov/facade.go b/core/discov/facade.go
deleted file mode 100644
index 2a7838f2..00000000
--- a/core/discov/facade.go
+++ /dev/null
@@ -1,47 +0,0 @@
-package discov
-
-import (
-	"github.com/tal-tech/go-zero/core/discov/internal"
-	"github.com/tal-tech/go-zero/core/logx"
-)
-
-type (
-	Facade struct {
-		endpoints []string
-		registry  *internal.Registry
-	}
-
-	FacadeListener interface {
-		OnAdd(key, val string)
-		OnDelete(key string)
-	}
-)
-
-func NewFacade(endpoints []string) Facade {
-	return Facade{
-		endpoints: endpoints,
-		registry:  internal.GetRegistry(),
-	}
-}
-
-func (f Facade) Client() internal.EtcdClient {
-	conn, err := f.registry.GetConn(f.endpoints)
-	logx.Must(err)
-	return conn
-}
-
-func (f Facade) Monitor(key string, l FacadeListener) {
-	f.registry.Monitor(f.endpoints, key, listenerAdapter{l})
-}
-
-type listenerAdapter struct {
-	l FacadeListener
-}
-
-func (la listenerAdapter) OnAdd(kv internal.KV) {
-	la.l.OnAdd(kv.Key, kv.Val)
-}
-
-func (la listenerAdapter) OnDelete(kv internal.KV) {
-	la.l.OnDelete(kv.Key)
-}
diff --git a/example/etcd/demo/Dockerfile b/example/etcd/demo/Dockerfile
deleted file mode 100644
index d4675b85..00000000
--- a/example/etcd/demo/Dockerfile
+++ /dev/null
@@ -1,27 +0,0 @@
-FROM golang:alpine AS builder
-
-LABEL stage=gobuilder
-
-ENV CGO_ENABLED 0
-ENV GOOS linux
-ENV GOPROXY https://goproxy.cn,direct
-
-RUN apk add upx
-
-WORKDIR $GOPATH/src/zero
-COPY . .
-RUN go build -ldflags="-s -w" -o /app/etcdmon example/etcd/demo/etcdmon.go
-RUN upx -q /app/etcdmon
-
-
-FROM alpine
-
-RUN apk update --no-cache
-RUN apk add --no-cache ca-certificates
-RUN apk add --no-cache tzdata
-ENV TZ Asia/Shanghai
-
-WORKDIR /app
-COPY --from=builder /app/etcdmon /app/etcdmon
-
-CMD ["./etcdmon"]
diff --git a/example/etcd/demo/etcdmon.go b/example/etcd/demo/etcdmon.go
deleted file mode 100644
index 3895b458..00000000
--- a/example/etcd/demo/etcdmon.go
+++ /dev/null
@@ -1,165 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"strings"
-	"time"
-
-	"github.com/tal-tech/go-zero/core/discov"
-	"github.com/tal-tech/go-zero/core/logx"
-	"github.com/tal-tech/go-zero/core/proc"
-	"github.com/tal-tech/go-zero/core/syncx"
-	"go.etcd.io/etcd/clientv3"
-)
-
-var (
-	endpoints []string
-	keys      = []string{
-		"user.rpc",
-		"classroom.rpc",
-	}
-	vals    = make(map[string]map[string]string)
-	barrier syncx.Barrier
-)
-
-type listener struct {
-	key string
-}
-
-func init() {
-	cluster := proc.Env("ETCD_CLUSTER")
-	if len(cluster) > 0 {
-		endpoints = strings.Split(cluster, ",")
-	} else {
-		endpoints = []string{"localhost:2379"}
-	}
-}
-
-func (l listener) OnAdd(key, val string) {
-	fmt.Printf("add, key: %s, val: %s\n", key, val)
-	barrier.Guard(func() {
-		if m, ok := vals[l.key]; ok {
-			m[key] = val
-		} else {
-			vals[l.key] = map[string]string{key: val}
-		}
-	})
-}
-
-func (l listener) OnDelete(key string) {
-	fmt.Printf("del, key: %s\n", key)
-	barrier.Guard(func() {
-		if m, ok := vals[l.key]; ok {
-			delete(m, key)
-		}
-	})
-}
-
-func load(cli *clientv3.Client, key string) (map[string]string, error) {
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-	resp, err := cli.Get(ctx, key, clientv3.WithPrefix())
-	cancel()
-	if err != nil {
-		return nil, err
-	}
-
-	ret := make(map[string]string)
-	for _, ev := range resp.Kvs {
-		ret[string(ev.Key)] = string(ev.Value)
-	}
-
-	return ret, nil
-}
-
-func loadAll(cli *clientv3.Client) (map[string]map[string]string, error) {
-	ret := make(map[string]map[string]string)
-	for _, key := range keys {
-		m, err := load(cli, key)
-		if err != nil {
-			return nil, err
-		}
-
-		ret[key] = m
-	}
-
-	return ret, nil
-}
-
-func compare(a, b map[string]map[string]string) bool {
-	if len(a) != len(b) {
-		return false
-	}
-
-	for k := range a {
-		av := a[k]
-		bv := b[k]
-		if len(av) != len(bv) {
-			return false
-		}
-
-		for kk := range av {
-			if av[kk] != bv[kk] {
-				return false
-			}
-		}
-	}
-
-	return true
-}
-
-func serializeMap(m map[string]map[string]string, prefix string) string {
-	var builder strings.Builder
-	for k, v := range m {
-		fmt.Fprintf(&builder, "%s%s:\n", prefix, k)
-		for kk, vv := range v {
-			fmt.Fprintf(&builder, "%s\t%s: %s\n", prefix, kk, vv)
-		}
-	}
-	return builder.String()
-}
-
-func main() {
-	registry := discov.NewFacade(endpoints)
-	for _, key := range keys {
-		registry.Monitor(key, listener{key: key})
-	}
-
-	ticker := time.NewTicker(time.Minute)
-	defer ticker.Stop()
-
-	for range ticker.C {
-		expect, err := loadAll(registry.Client().(*clientv3.Client))
-		if err != nil {
-			fmt.Println("[ETCD-test] can't load current keys")
-			continue
-		}
-
-		check := func() bool {
-			var match bool
-			barrier.Guard(func() {
-				match = compare(expect, vals)
-			})
-			if match {
-				logx.Info("match")
-			}
-			return match
-		}
-		if check() {
-			continue
-		}
-
-		time.AfterFunc(time.Second*5, func() {
-			if check() {
-				return
-			}
-
-			var builder strings.Builder
-			builder.WriteString(fmt.Sprintf("expect:\n%s\n", serializeMap(expect, "\t")))
-			barrier.Guard(func() {
-				builder.WriteString(fmt.Sprintf("actual:\n%s\n", serializeMap(vals, "\t")))
-			})
-			fmt.Println(builder.String())
-		})
-	}
-}