@@ -21,7 +21,7 @@ func (cli *DockerCli) CmdKill(args ...string) error {

 	var errs []string

 	for _, name := range cmd.Args() {

 		if err := cli.client.ContainerKill(name, *signal); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to kill container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -20,7 +20,7 @@ func (cli *DockerCli) CmdPause(args ...string) error {

 	var errs []string

 	for _, name := range cmd.Args() {

 		if err := cli.client.ContainerPause(name); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to pause container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -21,7 +21,7 @@ func (cli *DockerCli) CmdRestart(args ...string) error {

 	var errs []string

 	for _, name := range cmd.Args() {

 		if err := cli.client.ContainerRestart(name, *nSeconds); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to kill container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -48,7 +48,7 @@ func (cli *DockerCli) removeContainer(containerID string, removeVolumes, removeL

 		Force:         force,

 	}

 	if err := cli.client.ContainerRemove(options); err != nil {

-		return fmt.Errorf("Failed to remove container (%s): %v", containerID, err)

+		return err

 	}

 	return nil

 }

@@ -39,7 +39,7 @@ func (cli *DockerCli) CmdRmi(args ...string) error {

 		dels, err := cli.client.ImageRemove(options)

 		if err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to remove image (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			for _, del := range dels {

 				if del.Deleted != "" {

@@ -23,7 +23,7 @@ func (cli *DockerCli) CmdStop(args ...string) error {

 	var errs []string

 	for _, name := range cmd.Args() {

 		if err := cli.client.ContainerStop(name, *nSeconds); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to stop container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -20,7 +20,7 @@ func (cli *DockerCli) CmdUnpause(args ...string) error {

 	var errs []string

 	for _, name := range cmd.Args() {

 		if err := cli.client.ContainerUnpause(name); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to unpause container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -90,7 +90,7 @@ func (cli *DockerCli) CmdUpdate(args ...string) error {

 	var errs []string

 	for _, name := range names {

 		if err := cli.client.ContainerUpdate(name, updateConfig); err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to update container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%s\n", name)

 		}

@@ -23,7 +23,7 @@ func (cli *DockerCli) CmdWait(args ...string) error {

 	for _, name := range cmd.Args() {

 		status, err := cli.client.ContainerWait(name)

 		if err != nil {

-			errs = append(errs, fmt.Sprintf("Failed to wait container (%s): %s", name, err))

+			errs = append(errs, err.Error())

 		} else {

 			fmt.Fprintf(cli.out, "%d\n", status)

 		}

@@ -30,7 +30,7 @@ func (daemon *Daemon) ContainerRm(name string, config *types.ContainerRmConfig)

 			// do not fail when the removal is in progress started by other request.

 			return nil

 		}

-		return derr.ErrorCodeRmState.WithArgs(err)

+		return derr.ErrorCodeRmState.WithArgs(container.ID, err)

 	}

 	defer container.ResetRemovalInProgress()

@@ -84,10 +84,10 @@ func (daemon *Daemon) rmLink(container *container.Container, name string) error

 func (daemon *Daemon) cleanupContainer(container *container.Container, forceRemove bool) (err error) {

 	if container.IsRunning() {

 		if !forceRemove {

-			return derr.ErrorCodeRmRunning

+			return derr.ErrorCodeRmRunning.WithArgs(container.ID)

 		}

 		if err := daemon.Kill(container); err != nil {

-			return derr.ErrorCodeRmFailed.WithArgs(err)

+			return derr.ErrorCodeRmFailed.WithArgs(container.ID, err)

 		}

 	}

@@ -62,7 +62,7 @@ func (daemon *Daemon) killWithSignal(container *container.Container, sig int) er

 	}

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

-		return err

+		return derr.ErrorCodeCantKill.WithArgs(container.ID, err)

 	}

 	attributes := map[string]string{

@@ -13,7 +13,7 @@ func (daemon *Daemon) ContainerPause(name string) error {

 	}

 	if err := daemon.containerPause(container); err != nil {

-		return derr.ErrorCodePauseError.WithArgs(name, err)

+		return err

 	}

 	return nil

@@ -36,7 +36,7 @@ func (daemon *Daemon) containerPause(container *container.Container) error {

 	}

 	if err := daemon.execDriver.Pause(container.Command); err != nil {

-		return err

+		return derr.ErrorCodeCantPause.WithArgs(container.ID, err)

 	}

 	container.Paused = true

 	daemon.LogContainerEvent(container, "pause")

@@ -20,7 +20,7 @@ func (daemon *Daemon) ContainerStop(name string, seconds int) error {

 		return err

 	}

 	if !container.IsRunning() {

-		return derr.ErrorCodeStopped

+		return derr.ErrorCodeStopped.WithArgs(name)

 	}

 	if err := daemon.containerStop(container, seconds); err != nil {

 		return derr.ErrorCodeCantStop.WithArgs(name, err)

@@ -13,7 +13,7 @@ func (daemon *Daemon) ContainerUnpause(name string) error {

 	}

 	if err := daemon.containerUnpause(container); err != nil {

-		return derr.ErrorCodeCantUnpause.WithArgs(name, err)

+		return err

 	}

 	return nil

@@ -35,7 +35,7 @@ func (daemon *Daemon) containerUnpause(container *container.Container) error {

 	}

 	if err := daemon.execDriver.Unpause(container.Command); err != nil {

-		return err

+		return derr.ErrorCodeCantUnpause.WithArgs(container.ID, err)

 	}

 	container.Paused = false

@@ -3,6 +3,7 @@ package daemon

 import (

 	"fmt"

+	derr "github.com/docker/docker/errors"

 	"github.com/docker/engine-api/types/container"

 )

@@ -44,15 +45,17 @@ func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) erro

 	}

 	if container.RemovalInProgress || container.Dead {

-		return fmt.Errorf("Container is marked for removal and cannot be \"update\".")

+		errMsg := fmt.Errorf("Container is marked for removal and cannot be \"update\".")

+		return derr.ErrorCodeCantUpdate.WithArgs(container.ID, errMsg)

 	}

 	if container.IsRunning() && hostConfig.KernelMemory != 0 {

-		return fmt.Errorf("Can not update kernel memory to a running container, please stop it first.")

+		errMsg := fmt.Errorf("Can not update kernel memory to a running container, please stop it first.")

+		return derr.ErrorCodeCantUpdate.WithArgs(container.ID, errMsg)

 	}

 	if err := container.UpdateContainer(hostConfig); err != nil {

-		return err

+		return derr.ErrorCodeCantUpdate.WithArgs(container.ID, err.Error())

 	}

 	// If container is not running, update hostConfig struct is enough,

@@ -61,7 +64,7 @@ func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) erro

 	// to the real world.

 	if container.IsRunning() {

 		if err := daemon.execDriver.Update(container.Command); err != nil {

-			return err

+			return derr.ErrorCodeCantUpdate.WithArgs(container.ID, err.Error())

 		}

 	}

@@ -478,6 +478,15 @@ var (

 		HTTPStatusCode: http.StatusInternalServerError,

 	})

+	// ErrorCodeCantPause is generated when there's an error while trying

+	// to pause a container.

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

+		Value:          "CANTPAUSE",

+		Message:        "Cannot pause container %s: %s",

+		Description:    "An error occurred while trying to pause the specified container",

+		HTTPStatusCode: http.StatusInternalServerError,

+	})

+

 	// ErrorCodeCantUnpause is generated when there's an error while trying

 	// to unpause a container.

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

@@ -487,6 +496,23 @@ var (

 		HTTPStatusCode: http.StatusInternalServerError,

 	})

+	// ErrorCodeCantKill is generated when there's an error while trying

+	// to kill a container.

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

+		Value:          "CANTKILL",

+		Message:        "Cannot kill container %s: %s",

+		Description:    "An error occurred while trying to kill the specified container",

+		HTTPStatusCode: http.StatusInternalServerError,

+	})

+

+	// ErrorCodeCantUpdate is generated when there's an error while trying

+	// to update a container.

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

+		Value:          "CANTUPDATE",

+		Message:        "Cannot update container %s: %s",

+		Description:    "An error occurred while trying to update the specified container",

+		HTTPStatusCode: http.StatusInternalServerError,

+	})

 	// ErrorCodePSError is generated when trying to run 'ps'.

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

 		Value:          "PSError",

@@ -525,7 +551,7 @@ var (

 	// that is already stopped.

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

 		Value:          "STOPPED",

-		Message:        "Container already stopped",

+		Message:        "Container %s is already stopped",

 		Description:    "An attempt was made to stop a container, but the container is already stopped",

 		HTTPStatusCode: http.StatusNotModified,

 	})

@@ -818,7 +844,7 @@ var (

 	// but its still running.

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

 		Value:          "RMRUNNING",

-		Message:        "Conflict, You cannot remove a running container. Stop the container before attempting removal or use -f",

+		Message:        "You cannot remove a running container %s. Stop the container before attempting removal or use -f",

 		Description:    "An attempt was made to delete a container but the container is still running, try to either stop it first or use '-f'",

 		HTTPStatusCode: http.StatusConflict,

 	})

@@ -827,7 +853,7 @@ var (

 	// but it failed for some reason.

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

 		Value:          "RMFAILED",

-		Message:        "Could not kill running container, cannot remove - %v",

+		Message:        "Could not kill running container %s, cannot remove - %v",

 		Description:    "An error occurred while trying to delete a running container",

 		HTTPStatusCode: http.StatusInternalServerError,

 	})

@@ -845,7 +871,7 @@ var (

 	// but couldn't set its state to RemovalInProgress.

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

 		Value:          "RMSTATE",

-		Message:        "Failed to set container state to RemovalInProgress: %s",

+		Message:        "Failed to set container %s state to RemovalInProgress: %s",

 		Description:    "An attempt to delete a container was made, but there as an error trying to set its state to 'RemovalInProgress'",

 		HTTPStatusCode: http.StatusInternalServerError,

 	})

@@ -2,7 +2,6 @@ package main

 import (

 	"os"

-	"strings"

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

 	"github.com/go-check/check"

@@ -71,11 +70,9 @@ func (s *DockerSuite) TestRmContainerOrphaning(c *check.C) {

 }

 func (s *DockerSuite) TestRmInvalidContainer(c *check.C) {

-	if out, _, err := dockerCmdWithError("rm", "unknown"); err == nil {

-		c.Fatal("Expected error on rm unknown container, got none")

-	} else if !strings.Contains(out, "Failed to remove container") {

-		c.Fatalf("Expected output to contain 'Failed to remove container', got %q", out)

-	}

+	out, _, err := dockerCmdWithError("rm", "unknown")

+	c.Assert(err, checker.NotNil, check.Commentf("Expected error on rm unknown container, got none"))

+	c.Assert(out, checker.Contains, "No such container")

 }

 func createRunningContainer(c *check.C, name string) {