@@ -4,10 +4,10 @@ import (

 	"context"

 	"fmt"

 	"runtime"

-	"strings"

 	"syscall"

 	"time"

+	"github.com/docker/docker/api/errdefs"

 	containerpkg "github.com/docker/docker/container"

 	"github.com/docker/docker/libcontainerd"

 	"github.com/docker/docker/pkg/signal"

@@ -97,15 +97,11 @@ func (daemon *Daemon) killWithSignal(container *containerpkg.Container, sig int)

 	}

 	if err := daemon.kill(container, sig); err != nil {

-		err = errors.Wrapf(err, "Cannot kill container %s", container.ID)

-		// if container or process not exists, ignore the error

-		// TODO: we shouldn't have to parse error strings from containerd

-		if strings.Contains(err.Error(), "container not found") ||

-			strings.Contains(err.Error(), "no such process") {

-			logrus.Warnf("container kill failed because of 'container not found' or 'no such process': %s", err.Error())

+		if errdefs.IsNotFound(err) {

 			unpause = false

+			logrus.WithError(err).WithField("container", container.ID).WithField("action", "kill").Debug("container kill failed because of 'container not found' or 'no such process'")

 		} else {

-			return err

+			return errors.Wrapf(err, "Cannot kill container %s", container.ID)

 		}

 	}

@@ -171,7 +167,7 @@ func (daemon *Daemon) Kill(container *containerpkg.Container) error {

 // killPossibleDeadProcess is a wrapper around killSig() suppressing "no such process" error.

 func (daemon *Daemon) killPossiblyDeadProcess(container *containerpkg.Container, sig int) error {

 	err := daemon.killWithSignal(container, sig)

-	if err == syscall.ESRCH {

+	if errdefs.IsNotFound(err) {

 		e := errNoSuchProcess{container.GetPID(), sig}

 		logrus.Debug(e)

 		return e

@@ -27,6 +27,7 @@ import (

 	"github.com/containerd/containerd/archive"

 	"github.com/containerd/containerd/cio"

 	"github.com/containerd/containerd/content"

+	"github.com/containerd/containerd/errdefs"

 	"github.com/containerd/containerd/images"

 	"github.com/containerd/containerd/linux/runctypes"

 	"github.com/containerd/typeurl"

@@ -317,7 +318,7 @@ func (c *client) SignalProcess(ctx context.Context, containerID, processID strin

 	if err != nil {

 		return err

 	}

-	return p.Kill(ctx, syscall.Signal(signal))

+	return wrapError(p.Kill(ctx, syscall.Signal(signal)))

 }

 func (c *client) ResizeTerminal(ctx context.Context, containerID, processID string, width, height int) error {

@@ -816,12 +817,19 @@ func (c *client) writeContent(ctx context.Context, mediaType, ref string, r io.R

 }

 func wrapError(err error) error {

-	if err != nil {

-		msg := err.Error()

-		for _, s := range []string{"container does not exist", "not found", "no such container"} {

-			if strings.Contains(msg, s) {

-				return wrapNotFoundError(err)

-			}

+	if err == nil {

+		return nil

+	}

+

+	switch {

+	case errdefs.IsNotFound(err):

+		return wrapNotFoundError(err)

+	}

+

+	msg := err.Error()

+	for _, s := range []string{"container does not exist", "not found", "no such container"} {

+		if strings.Contains(msg, s) {

+			return wrapNotFoundError(err)

 		}

 	}

 	return err