@@ -41,6 +41,10 @@ func (cli *DockerCli) CmdAttach(args ...string) error {

 		return fmt.Errorf("You cannot attach to a stopped container, start it first")

 	}

+	if c.State.Paused {

+		return fmt.Errorf("You cannot attach to a paused container, unpause it first")

+	}

+

 	if err := cli.CheckTtyInput(!*noStdin, c.Config.Tty); err != nil {

 		return err

 	}

@@ -396,6 +396,10 @@ func (s *router) postContainersAttach(ctx context.Context, w http.ResponseWriter

 		return derr.ErrorCodeNoSuchContainer.WithArgs(containerName)

 	}

+	if s.daemon.IsPaused(containerName) {

+		return derr.ErrorCodePausedContainer.WithArgs(containerName)

+	}

+

 	inStream, outStream, err := httputils.HijackConnection(w)

 	if err != nil {

 		return err

@@ -163,6 +163,12 @@ func (daemon *Daemon) Exists(id string) bool {

 	return c != nil

 }

+// IsPaused returns a bool indicating if the specified container is paused.

+func (daemon *Daemon) IsPaused(id string) bool {

+	c, _ := daemon.Get(id)

+	return c.State.isPaused()

+}

+

 func (daemon *Daemon) containerRoot(id string) string {

 	return filepath.Join(daemon.repository, id)

 }

@@ -46,6 +46,14 @@ var (

 		HTTPStatusCode: http.StatusInternalServerError,

 	})

+	// ErrorCodePausedContainer is generated when we attempt to attach a

+	// container but its paused.

+	ErrorCodePausedContainer = errcode.Register(errGroup, errcode.ErrorDescriptor{

+		Value:          "CONTAINERPAUSED",

+		Message:        "Container %s is paused. Unpause the container before attach",

+		Description:    "The specified container is paused, unpause the container before attach",

+		HTTPStatusCode: http.StatusConflict,

+	})

 	// ErrorCodeAlreadyPaused is generated when we attempt to pause a

 	// container when its already paused.

 	ErrorCodeAlreadyPaused = errcode.Register(errGroup, errcode.ErrorDescriptor{

@@ -9,6 +9,7 @@ import (

 	"sync"

 	"time"

+	"github.com/docker/docker/pkg/integration/checker"

 	"github.com/go-check/check"

 )

@@ -150,3 +151,12 @@ func (s *DockerSuite) TestAttachDisconnect(c *check.C) {

 	c.Assert(err, check.IsNil)

 	c.Assert(running, check.Equals, "true")

 }

+

+func (s *DockerSuite) TestAttachPausedContainer(c *check.C) {

+	defer unpauseAllContainers()

+	dockerCmd(c, "run", "-d", "--name=test", "busybox", "top")

+	dockerCmd(c, "pause", "test")

+	out, _, err := dockerCmdWithError("attach", "test")

+	c.Assert(err, checker.NotNil, check.Commentf(out))

+	c.Assert(out, checker.Contains, "You cannot attach to a paused container, unpause it first")

+}