diff --git a/server/etcdserver/api/rafthttp/pipeline.go b/server/etcdserver/api/rafthttp/pipeline.go
index 50b8c8dd3..0790b58d0 100644
--- a/server/etcdserver/api/rafthttp/pipeline.go
+++ b/server/etcdserver/api/rafthttp/pipeline.go
@@ -165,7 +165,7 @@ func (p *pipeline) post(data []byte) (err error) {
 		p.picker.unreachable(u)
 		// errMemberRemoved is a critical error since a removed member should
 		// always be stopped. So we use reportCriticalError to report it to errorc.
-		if err == errMemberRemoved {
+		if errors.Is(err, errMemberRemoved) {
 			reportCriticalError(err, p.errorc)
 		}
 		return err
diff --git a/server/etcdserver/api/rafthttp/snapshot_sender.go b/server/etcdserver/api/rafthttp/snapshot_sender.go
index 1f0253f14..07971cbbd 100644
--- a/server/etcdserver/api/rafthttp/snapshot_sender.go
+++ b/server/etcdserver/api/rafthttp/snapshot_sender.go
@@ -17,6 +17,7 @@ package rafthttp
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 	"net/http"
 	"time"
@@ -110,7 +111,7 @@ func (s *snapshotSender) send(merged snap.Message) {
 
 		// errMemberRemoved is a critical error since a removed member should
 		// always be stopped. So we use reportCriticalError to report it to errorc.
-		if err == errMemberRemoved {
+		if errors.Is(err, errMemberRemoved) {
 			reportCriticalError(err, s.errorc)
 		}
 
diff --git a/server/etcdserver/api/rafthttp/stream.go b/server/etcdserver/api/rafthttp/stream.go
index 63ffe8fdc..7b73fcd00 100644
--- a/server/etcdserver/api/rafthttp/stream.go
+++ b/server/etcdserver/api/rafthttp/stream.go
@@ -16,6 +16,7 @@ package rafthttp
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -428,7 +429,7 @@ func (cr *streamReader) run() {
 			}
 			switch {
 			// all data is read out
-			case err == io.EOF:
+			case errors.Is(err, io.EOF):
 			// connection is closed by the remote
 			case transport.IsClosedConnError(err):
 			default:
diff --git a/server/etcdserver/api/v2discovery/discovery.go b/server/etcdserver/api/v2discovery/discovery.go
index 5993d4458..fcdeb8290 100644
--- a/server/etcdserver/api/v2discovery/discovery.go
+++ b/server/etcdserver/api/v2discovery/discovery.go
@@ -187,7 +187,7 @@ func (d *discovery) joinCluster(config string) (string, error) {
 func (d *discovery) getCluster() (string, error) {
 	nodes, size, index, err := d.checkCluster()
 	if err != nil {
-		if err == ErrFullCluster {
+		if errors.Is(err, ErrFullCluster) {
 			return nodesToCluster(nodes, size)
 		}
 		return "", err
@@ -205,7 +205,8 @@ func (d *discovery) createSelf(contents string) error {
 	resp, err := d.c.Create(ctx, d.selfKey(), contents)
 	cancel()
 	if err != nil {
-		if eerr, ok := err.(client.Error); ok && eerr.Code == client.ErrorCodeNodeExist {
+		var eerr client.Error
+		if errors.As(err, &eerr) && eerr.Code == client.ErrorCodeNodeExist {
 			return ErrDuplicateID
 		}
 		return err
@@ -224,13 +225,15 @@ func (d *discovery) checkCluster() ([]*client.Node, uint64, uint64, error) {
 	resp, err := d.c.Get(ctx, path.Join(configKey, "size"), nil)
 	cancel()
 	if err != nil {
-		if eerr, ok := err.(*client.Error); ok && eerr.Code == client.ErrorCodeKeyNotFound {
+		var eerr *client.Error
+		if errors.As(err, &eerr) && eerr.Code == client.ErrorCodeKeyNotFound {
 			return nil, 0, 0, ErrSizeNotFound
 		}
-		if err == client.ErrInvalidJSON {
+		if errors.Is(err, client.ErrInvalidJSON) {
 			return nil, 0, 0, ErrBadDiscoveryEndpoint
 		}
-		if ce, ok := err.(*client.ClusterError); ok {
+		var ce *client.ClusterError
+		if errors.As(err, &ce) {
 			d.lg.Warn(
 				"failed to get from discovery server",
 				zap.String("discovery-url", d.url.String()),
@@ -251,7 +254,8 @@ func (d *discovery) checkCluster() ([]*client.Node, uint64, uint64, error) {
 	resp, err = d.c.Get(ctx, d.cluster, nil)
 	cancel()
 	if err != nil {
-		if ce, ok := err.(*client.ClusterError); ok {
+		var ce *client.ClusterError
+		if errors.As(err, &ce) {
 			d.lg.Warn(
 				"failed to get from discovery server",
 				zap.String("discovery-url", d.url.String()),
diff --git a/server/etcdserver/api/v3rpc/lease.go b/server/etcdserver/api/v3rpc/lease.go
index e03953935..4d215e630 100644
--- a/server/etcdserver/api/v3rpc/lease.go
+++ b/server/etcdserver/api/v3rpc/lease.go
@@ -16,6 +16,7 @@ package v3rpc
 
 import (
 	"context"
+	"errors"
 	"io"
 
 	"go.uber.org/zap"
@@ -61,10 +62,10 @@ func (ls *LeaseServer) LeaseRevoke(ctx context.Context, rr *pb.LeaseRevokeReques
 
 func (ls *LeaseServer) LeaseTimeToLive(ctx context.Context, rr *pb.LeaseTimeToLiveRequest) (*pb.LeaseTimeToLiveResponse, error) {
 	resp, err := ls.le.LeaseTimeToLive(ctx, rr)
-	if err != nil && err != lease.ErrLeaseNotFound {
+	if err != nil && !errors.Is(err, lease.ErrLeaseNotFound) {
 		return nil, togRPCError(err)
 	}
-	if err == lease.ErrLeaseNotFound {
+	if errors.Is(err, lease.ErrLeaseNotFound) {
 		resp = &pb.LeaseTimeToLiveResponse{
 			Header: &pb.ResponseHeader{},
 			ID:     rr.ID,
@@ -80,7 +81,7 @@ func (ls *LeaseServer) LeaseLeases(ctx context.Context, rr *pb.LeaseLeasesReques
 	if err != nil && !errors.Is(err, lease.ErrLeaseNotFound) {
 		return nil, togRPCError(err)
 	}
-	if err == lease.ErrLeaseNotFound {
+	if errors.Is(err, lease.ErrLeaseNotFound) {
 		resp = &pb.LeaseLeasesResponse{
 			Header: &pb.ResponseHeader{},
 			Leases: []*pb.LeaseStatus{},
@@ -100,7 +101,7 @@ func (ls *LeaseServer) LeaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) (err
 	case <-stream.Context().Done():
 		// the only server-side cancellation is noleader for now.
 		err = stream.Context().Err()
-		if err == context.Canceled {
+		if errors.Is(err, context.Canceled) {
 			err = rpctypes.ErrGRPCNoLeader
 		}
 	}
@@ -110,7 +111,7 @@ func (ls *LeaseServer) LeaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) (err
 func (ls *LeaseServer) leaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) error {
 	for {
 		req, err := stream.Recv()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		if err != nil {
@@ -133,7 +134,7 @@ func (ls *LeaseServer) leaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) erro
 		ls.hdr.fill(resp.Header)
 
 		ttl, err := ls.le.LeaseRenew(stream.Context(), lease.LeaseID(req.ID))
-		if err == lease.ErrLeaseNotFound {
+		if errors.Is(err, lease.ErrLeaseNotFound) {
 			err = nil
 			ttl = 0
 		}
diff --git a/server/etcdserver/api/v3rpc/util.go b/server/etcdserver/api/v3rpc/util.go
index a31e6cbec..2354b0cb2 100644
--- a/server/etcdserver/api/v3rpc/util.go
+++ b/server/etcdserver/api/v3rpc/util.go
@@ -16,6 +16,7 @@ package v3rpc
 
 import (
 	"context"
+	errorspkg "errors"
 	"strings"
 
 	"google.golang.org/grpc/codes"
@@ -95,7 +96,7 @@ var toGRPCErrorMap = map[error]error{
 
 func togRPCError(err error) error {
 	// let gRPC server convert to codes.Canceled, codes.DeadlineExceeded
-	if err == context.Canceled || err == context.DeadlineExceeded {
+	if errorspkg.Is(err, context.Canceled) || errorspkg.Is(err, context.DeadlineExceeded) {
 		return err
 	}
 	grpcErr, ok := toGRPCErrorMap[err]
diff --git a/server/etcdserver/api/v3rpc/watch.go b/server/etcdserver/api/v3rpc/watch.go
index 6e72b1ceb..2f0562960 100644
--- a/server/etcdserver/api/v3rpc/watch.go
+++ b/server/etcdserver/api/v3rpc/watch.go
@@ -16,6 +16,7 @@ package v3rpc
 
 import (
 	"context"
+	"errors"
 	"io"
 	"math/rand"
 	"sync"
@@ -211,13 +212,13 @@ func (ws *watchServer) Watch(stream pb.Watch_WatchServer) (err error) {
 	// revisited.
 	select {
 	case err = <-errc:
-		if err == context.Canceled {
+		if errors.Is(err, context.Canceled) {
 			err = rpctypes.ErrGRPCWatchCanceled
 		}
 		close(sws.ctrlStream)
 	case <-stream.Context().Done():
 		err = stream.Context().Err()
-		if err == context.Canceled {
+		if errors.Is(err, context.Canceled) {
 			err = rpctypes.ErrGRPCWatchCanceled
 		}
 	}
@@ -241,7 +242,7 @@ func (sws *serverWatchStream) isWatchPermitted(wcr *pb.WatchCreateRequest) error
 func (sws *serverWatchStream) recvLoop() error {
 	for {
 		req, err := sws.gRPCStream.Recv()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		if err != nil {
diff --git a/server/etcdserver/apply/apply_auth_test.go b/server/etcdserver/apply/apply_auth_test.go
index 6516f41b5..e7445a10a 100644
--- a/server/etcdserver/apply/apply_auth_test.go
+++ b/server/etcdserver/apply/apply_auth_test.go
@@ -16,6 +16,7 @@ package apply
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -387,8 +388,8 @@ func TestAuthApplierV3_AdminPermission(t *testing.T) {
 				tc.request.Header = &pb.RequestHeader{Username: userReadOnly}
 			}
 			result := authApplier.Apply(ctx, tc.request, dummyApplyFunc)
-			require.Equal(t, result.Err == auth.ErrPermissionDenied, tc.adminPermissionNeeded,
-				"Admin permission needed: got %v, expect: %v", result.Err == auth.ErrPermissionDenied, tc.adminPermissionNeeded)
+			require.Equal(t, errors.Is(result.Err, auth.ErrPermissionDenied), tc.adminPermissionNeeded,
+				"Admin permission needed: got %v, expect: %v", errors.Is(result.Err, auth.ErrPermissionDenied), tc.adminPermissionNeeded)
 		})
 	}
 }
diff --git a/server/lease/leasehttp/http.go b/server/lease/leasehttp/http.go
index 5837ac40b..9592b63cb 100644
--- a/server/lease/leasehttp/http.go
+++ b/server/lease/leasehttp/http.go
@@ -75,7 +75,7 @@ func (h *leaseHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 		ttl, rerr := h.l.Renew(lease.LeaseID(lreq.ID))
 		if rerr != nil {
-			if rerr == lease.ErrLeaseNotFound {
+			if errors.Is(rerr, lease.ErrLeaseNotFound) {
 				http.Error(w, rerr.Error(), http.StatusNotFound)
 				return
 			}
diff --git a/server/proxy/grpcproxy/lease.go b/server/proxy/grpcproxy/lease.go
index fdc936ca9..dc42dc5a0 100644
--- a/server/proxy/grpcproxy/lease.go
+++ b/server/proxy/grpcproxy/lease.go
@@ -16,6 +16,7 @@ package grpcproxy
 
 import (
 	"context"
+	"errors"
 	"io"
 	"sync"
 	"sync/atomic"
@@ -245,7 +246,7 @@ type leaseProxyStream struct {
 func (lps *leaseProxyStream) recvLoop() error {
 	for {
 		rr, err := lps.stream.Recv()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		if err != nil {
diff --git a/server/proxy/grpcproxy/maintenance.go b/server/proxy/grpcproxy/maintenance.go
index 50ecf67ff..553b66c4b 100644
--- a/server/proxy/grpcproxy/maintenance.go
+++ b/server/proxy/grpcproxy/maintenance.go
@@ -16,6 +16,7 @@ package grpcproxy
 
 import (
 	"context"
+	"errors"
 	"io"
 
 	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
@@ -50,7 +51,7 @@ func (mp *maintenanceProxy) Snapshot(sr *pb.SnapshotRequest, stream pb.Maintenan
 	for {
 		rr, err := sc.Recv()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				return nil
 			}
 			return err
diff --git a/server/storage/wal/decoder.go b/server/storage/wal/decoder.go
index 0f47b72fd..01ffbd52b 100644
--- a/server/storage/wal/decoder.go
+++ b/server/storage/wal/decoder.go
@@ -16,6 +16,7 @@ package wal
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"hash"
 	"io"
@@ -114,7 +115,7 @@ func (d *decoder) decodeRecord(rec *walpb.Record) error {
 	if _, err = io.ReadFull(fileBufReader, data); err != nil {
 		// ReadFull returns io.EOF only if no bytes were read
 		// the decoder should treat this as an ErrUnexpectedEOF instead.
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			err = io.ErrUnexpectedEOF
 		}
 		return err