docker/config: update -mtu flag default

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: google)

config.go

@@ -49,7 +49,7 @@ func DaemonConfigFromJob(job *engine.Job) *DaemonConfig {
 	if mtu := job.GetenvInt("Mtu"); mtu != 0 {
 		config.Mtu = mtu
 	} else {
-		config.Mtu = DefaultNetworkMtu
+		config.Mtu = GetDefaultNetworkMtu()
 	}
 	config.DisableNetwork = job.Getenv("BridgeIface") == DisableNetworkBridge
 

docker/docker.go

@@ -43,7 +43,7 @@ func main() {
 		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")
 		flHosts              = docker.NewListOpts(docker.ValidateHost)
-		flMtu                = flag.Int([]string{"#mtu", "-mtu"}, docker.GetDefaultNetworkMtu(), "Set the containers network mtu")
+		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 not default route is available")
 	)
 	flag.Var(&flDns, []string{"#dns", "-dns"}, "Force docker to use specific DNS servers")
 	flag.Var(&flHosts, []string{"H", "-host"}, "tcp://host:port, unix://path/to/socket, fd://* or fd://socketfd to use in daemon mode. Multiple sockets can be specified")

integration/utils_test.go

@@ -4,9 +4,6 @@ import (
 	"archive/tar"
 	"bytes"
 	"fmt"
-	"github.com/dotcloud/docker"
-	"github.com/dotcloud/docker/engine"
-	"github.com/dotcloud/docker/utils"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -16,6 +13,10 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/dotcloud/docker"
+	"github.com/dotcloud/docker/engine"
+	"github.com/dotcloud/docker/utils"
 )
 
 // This file contains utility functions for docker's unit test suite.
@@ -32,7 +33,7 @@ func mkRuntime(f utils.Fataler) *docker.Runtime {
 	config := &docker.DaemonConfig{
 		Root:        root,
 		AutoRestart: false,
-		Mtu:         docker.DefaultNetworkMtu,
+		Mtu:         docker.GetDefaultNetworkMtu(),
 	}
 
 	eng, err := engine.New(root)