@@ -25,6 +25,7 @@ type DaemonConfig struct {

 	BridgeIP                    string

 	InterContainerCommunication bool

 	GraphDriver                 string

+	ExecDriver                  string

 	Mtu                         int

 	DisableNetwork              bool

 }

@@ -43,6 +44,7 @@ func DaemonConfigFromJob(job *engine.Job) *DaemonConfig {

 		DefaultIp:                   net.ParseIP(job.Getenv("DefaultIp")),

 		InterContainerCommunication: job.GetenvBool("InterContainerCommunication"),

 		GraphDriver:                 job.Getenv("GraphDriver"),

+		ExecDriver:                  job.Getenv("ExecDriver"),

 	}

 	if dns := job.GetenvList("Dns"); dns != nil {

 		config.Dns = dns

@@ -39,6 +39,7 @@ func main() {

 		flDefaultIp          = flag.String([]string{"#ip", "-ip"}, "0.0.0.0", "Default IP address to use when binding container ports")

 		flInterContainerComm = flag.Bool([]string{"#icc", "-icc"}, true, "Enable inter-container communication")

 		flGraphDriver        = flag.String([]string{"s", "-storage-driver"}, "", "Force the docker runtime to use a specific storage driver")

+		flExecDriver         = flag.String([]string{"e", "-exec-driver"}, "", "Force the docker runtime to use a specific exec driver")

 		flHosts              = opts.NewListOpts(api.ValidateHost)

 		flMtu                = flag.Int([]string{"#mtu", "-mtu"}, 0, "Set the containers network MTU; if no value is provided: default to the default route MTU or 1500 if no default route is available")

 	)

@@ -100,6 +101,7 @@ func main() {

 			job.Setenv("DefaultIp", *flDefaultIp)

 			job.SetenvBool("InterContainerCommunication", *flInterContainerComm)

 			job.Setenv("GraphDriver", *flGraphDriver)

+			job.Setenv("ExecDriver", *flExecDriver)

 			job.SetenvInt("Mtu", *flMtu)

 			if err := job.Run(); err != nil {

 				log.Fatal(err)

@@ -79,6 +79,7 @@ Commands

       -p, --pidfile="/var/run/docker.pid": Path to use for daemon PID file

       -r, --restart=true: Restart previously running containers

       -s, --storage-driver="": Force the docker runtime to use a specific storage driver

+      -e, --exec-driver="": Force the docker runtime to use a specific exec driver

       -v, --version=false: Print version information and quit

       --mtu=0: Set the containers network MTU; if no value is provided: default to the default route MTU or 1500 if no default route is available

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

 	"github.com/dotcloud/docker/dockerversion"

 	"github.com/dotcloud/docker/engine"

 	"github.com/dotcloud/docker/execdriver"

+	"github.com/dotcloud/docker/execdriver/chroot"

 	"github.com/dotcloud/docker/execdriver/lxc"

 	"github.com/dotcloud/docker/graphdriver"

 	"github.com/dotcloud/docker/graphdriver/aufs"

@@ -703,7 +704,16 @@ func NewRuntimeFromDirectory(config *DaemonConfig, eng *engine.Engine) (*Runtime

 	sysInfo := sysinfo.New(false)

-	ed, err := lxc.NewDriver(config.Root, sysInfo.AppArmor)

+	var ed execdriver.Driver

+	utils.Debugf("execDriver: provided %s", config.ExecDriver)

+	if config.ExecDriver == "chroot" && false {

+		// chroot is presently a noop driver https://github.com/dotcloud/docker/pull/4189#issuecomment-35330655

+		ed, err = chroot.NewDriver()

+		utils.Debugf("execDriver: using chroot")

+	} else {

+		ed, err = lxc.NewDriver(config.Root, sysInfo.AppArmor)

+		utils.Debugf("execDriver: using lxc")

+	}

 	if err != nil {

 		return nil, err

 	}