@@ -152,7 +152,28 @@ func (container *Container) readHostConfig() error {

 	}

 	defer f.Close()

-	return json.NewDecoder(f).Decode(&container.hostConfig)

+	if err := json.NewDecoder(f).Decode(&container.hostConfig); err != nil {

+		return err

+	}

+

+	// Make sure the dns fields are never nil.

+	// New containers don't ever have those fields nil,

+	// but pre created containers can still have those nil values.

+	// See https://github.com/docker/docker/pull/17779

+	// for a more detailed explanation on why we don't want that.

+	if container.hostConfig.DNS == nil {

+		container.hostConfig.DNS = make([]string, 0)

+	}

+

+	if container.hostConfig.DNSSearch == nil {

+		container.hostConfig.DNSSearch = make([]string, 0)

+	}

+

+	if container.hostConfig.DNSOptions == nil {

+		container.hostConfig.DNSOptions = make([]string, 0)

+	}

+

+	return nil

 }

 func (container *Container) writeHostConfig() error {

@@ -1,10 +1,15 @@

 package daemon

 import (

+	"io/ioutil"

+	"os"

+	"path/filepath"

 	"testing"

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

 	"github.com/docker/docker/runconfig"

+	"github.com/docker/docker/volume"

+	"github.com/docker/docker/volume/drivers"

 )

 func TestGetFullName(t *testing.T) {

@@ -64,3 +69,68 @@ func TestContainerStopSignal(t *testing.T) {

 		t.Fatalf("Expected 9, got %v", s)

 	}

 }

+

+func TestContainerInitDNS(t *testing.T) {

+	tmp, err := ioutil.TempDir("", "docker-container-test-")

+	if err != nil {

+		t.Fatal(err)

+	}

+	defer os.RemoveAll(tmp)

+

+	containerID := "d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e"

+	containerPath := filepath.Join(tmp, containerID)

+	if err := os.MkdirAll(containerPath, 0755); err != nil {

+		t.Fatal(err)

+	}

+

+	config := `{"State":{"Running":true,"Paused":false,"Restarting":false,"OOMKilled":false,"Dead":false,"Pid":2464,"ExitCode":0,

+"Error":"","StartedAt":"2015-05-26T16:48:53.869308965Z","FinishedAt":"0001-01-01T00:00:00Z"},

+"ID":"d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e","Created":"2015-05-26T16:48:53.7987917Z","Path":"top",

+"Args":[],"Config":{"Hostname":"d59df5276e7b","Domainname":"","User":"","Memory":0,"MemorySwap":0,"CpuShares":0,"Cpuset":"",

+"AttachStdin":false,"AttachStdout":false,"AttachStderr":false,"PortSpecs":null,"ExposedPorts":null,"Tty":true,"OpenStdin":true,

+"StdinOnce":false,"Env":null,"Cmd":["top"],"Image":"ubuntu:latest","Volumes":null,"WorkingDir":"","Entrypoint":null,

+"NetworkDisabled":false,"MacAddress":"","OnBuild":null,"Labels":{}},"Image":"07f8e8c5e66084bef8f848877857537ffe1c47edd01a93af27e7161672ad0e95",

+"NetworkSettings":{"IPAddress":"172.17.0.1","IPPrefixLen":16,"MacAddress":"02:42:ac:11:00:01","LinkLocalIPv6Address":"fe80::42:acff:fe11:1",

+"LinkLocalIPv6PrefixLen":64,"GlobalIPv6Address":"","GlobalIPv6PrefixLen":0,"Gateway":"172.17.42.1","IPv6Gateway":"","Bridge":"docker0","Ports":{}},

+"ResolvConfPath":"/var/lib/docker/containers/d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e/resolv.conf",

+"HostnamePath":"/var/lib/docker/containers/d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e/hostname",

+"HostsPath":"/var/lib/docker/containers/d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e/hosts",

+"LogPath":"/var/lib/docker/containers/d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e/d59df5276e7b219d510fe70565e0404bc06350e0d4b43fe961f22f339980170e-json.log",

+"Name":"/ubuntu","Driver":"aufs","MountLabel":"","ProcessLabel":"","AppArmorProfile":"","RestartCount":0,

+"UpdateDns":false,"Volumes":{},"VolumesRW":{},"AppliedVolumesFrom":null}`

+

+	if err = ioutil.WriteFile(filepath.Join(containerPath, "config.json"), []byte(config), 0644); err != nil {

+		t.Fatal(err)

+	}

+

+	hostConfig := `{"Binds":[],"ContainerIDFile":"","Memory":0,"MemorySwap":0,"CpuShares":0,"CpusetCpus":"",

+"Privileged":false,"PortBindings":{},"Links":null,"PublishAllPorts":false,"Dns":null,"DnsOptions":null,"DnsSearch":null,"ExtraHosts":null,"VolumesFrom":null,

+"Devices":[],"NetworkMode":"bridge","IpcMode":"","PidMode":"","CapAdd":null,"CapDrop":null,"RestartPolicy":{"Name":"no","MaximumRetryCount":0},

+"SecurityOpt":null,"ReadonlyRootfs":false,"Ulimits":null,"LogConfig":{"Type":"","Config":null},"CgroupParent":""}`

+	if err = ioutil.WriteFile(filepath.Join(containerPath, "hostconfig.json"), []byte(hostConfig), 0644); err != nil {

+		t.Fatal(err)

+	}

+

+	daemon, err := initDaemonWithVolumeStore(tmp)

+	if err != nil {

+		t.Fatal(err)

+	}

+	defer volumedrivers.Unregister(volume.DefaultDriverName)

+

+	c, err := daemon.load(containerID)

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	if c.hostConfig.DNS == nil {

+		t.Fatal("Expected container DNS to not be nil")

+	}

+

+	if c.hostConfig.DNSSearch == nil {

+		t.Fatal("Expected container DNSSearch to not be nil")

+	}

+

+	if c.hostConfig.DNSOptions == nil {

+		t.Fatal("Expected container DNSOptions to not be nil")

+	}

+}

@@ -182,7 +182,7 @@ func TestLoadWithVolume(t *testing.T) {

 		t.Fatal(err)

 	}

-	daemon, err := initDaemonForVolumesTest(tmp)

+	daemon, err := initDaemonWithVolumeStore(tmp)

 	if err != nil {

 		t.Fatal(err)

 	}

@@ -270,7 +270,7 @@ func TestLoadWithBindMount(t *testing.T) {

 		t.Fatal(err)

 	}

-	daemon, err := initDaemonForVolumesTest(tmp)

+	daemon, err := initDaemonWithVolumeStore(tmp)

 	if err != nil {

 		t.Fatal(err)

 	}

@@ -361,7 +361,7 @@ func TestLoadWithVolume17RC(t *testing.T) {

 		t.Fatal(err)

 	}

-	daemon, err := initDaemonForVolumesTest(tmp)

+	daemon, err := initDaemonWithVolumeStore(tmp)

 	if err != nil {

 		t.Fatal(err)

 	}

@@ -466,7 +466,7 @@ func TestRemoveLocalVolumesFollowingSymlinks(t *testing.T) {

 		t.Fatal(err)

 	}

-	daemon, err := initDaemonForVolumesTest(tmp)

+	daemon, err := initDaemonWithVolumeStore(tmp)

 	if err != nil {

 		t.Fatal(err)

 	}

@@ -502,7 +502,7 @@ func TestRemoveLocalVolumesFollowingSymlinks(t *testing.T) {

 	}

 }

-func initDaemonForVolumesTest(tmp string) (*Daemon, error) {

+func initDaemonWithVolumeStore(tmp string) (*Daemon, error) {

 	daemon := &Daemon{

 		repository: tmp,

 		root:       tmp,

@@ -329,3 +329,11 @@ func (s *DockerSuite) TestInspectTempateError(c *check.C) {

 	c.Assert(err, check.Not(check.IsNil))

 	c.Assert(out, checker.Contains, "Template parsing error")

 }

+

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

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

+	out, _, err := dockerCmdWithError("inspect", "--type=container", "--format='{{.HostConfig.Dns}}'", "busybox")

+

+	c.Assert(err, check.IsNil)

+	c.Assert(out, checker.Equals, "[]\n")

+}

@@ -98,6 +98,16 @@ func (opts *ListOpts) GetAll() []string {

 	return (*opts.values)

 }

+// GetAllOrEmpty returns the values of the slice

+// or an empty slice when there are no values.

+func (opts *ListOpts) GetAllOrEmpty() []string {

+	v := *opts.values

+	if v == nil {

+		return make([]string, 0)

+	}

+	return v

+}

+

 // Get checks the existence of the specified key.

 func (opts *ListOpts) Get(key string) bool {

 	for _, k := range *opts.values {

@@ -348,27 +348,32 @@ func Parse(cmd *flag.FlagSet, args []string) (*Config, *HostConfig, *flag.FlagSe

 		PortBindings:      portBindings,

 		Links:             flLinks.GetAll(),

 		PublishAllPorts:   *flPublishAll,

-		DNS:               flDNS.GetAll(),

-		DNSSearch:         flDNSSearch.GetAll(),

-		DNSOptions:        flDNSOptions.GetAll(),

-		ExtraHosts:        flExtraHosts.GetAll(),

-		VolumesFrom:       flVolumesFrom.GetAll(),

-		NetworkMode:       NetworkMode(*flNetMode),

-		IpcMode:           ipcMode,

-		PidMode:           pidMode,

-		UTSMode:           utsMode,

-		Devices:           deviceMappings,

-		CapAdd:            stringutils.NewStrSlice(flCapAdd.GetAll()...),

-		CapDrop:           stringutils.NewStrSlice(flCapDrop.GetAll()...),

-		GroupAdd:          flGroupAdd.GetAll(),

-		RestartPolicy:     restartPolicy,

-		SecurityOpt:       flSecurityOpt.GetAll(),

-		ReadonlyRootfs:    *flReadonlyRootfs,

-		Ulimits:           flUlimits.GetList(),

-		LogConfig:         LogConfig{Type: *flLoggingDriver, Config: loggingOpts},

-		CgroupParent:      *flCgroupParent,

-		VolumeDriver:      *flVolumeDriver,

-		Isolation:         IsolationLevel(*flIsolation),

+		// Make sure the dns fields are never nil.

+		// New containers don't ever have those fields nil,

+		// but pre created containers can still have those nil values.

+		// See https://github.com/docker/docker/pull/17779

+		// for a more detailed explanation on why we don't want that.

+		DNS:            flDNS.GetAllOrEmpty(),

+		DNSSearch:      flDNSSearch.GetAllOrEmpty(),

+		DNSOptions:     flDNSOptions.GetAllOrEmpty(),

+		ExtraHosts:     flExtraHosts.GetAll(),

+		VolumesFrom:    flVolumesFrom.GetAll(),

+		NetworkMode:    NetworkMode(*flNetMode),

+		IpcMode:        ipcMode,

+		PidMode:        pidMode,

+		UTSMode:        utsMode,

+		Devices:        deviceMappings,

+		CapAdd:         stringutils.NewStrSlice(flCapAdd.GetAll()...),

+		CapDrop:        stringutils.NewStrSlice(flCapDrop.GetAll()...),

+		GroupAdd:       flGroupAdd.GetAll(),

+		RestartPolicy:  restartPolicy,

+		SecurityOpt:    flSecurityOpt.GetAll(),

+		ReadonlyRootfs: *flReadonlyRootfs,

+		Ulimits:        flUlimits.GetList(),

+		LogConfig:      LogConfig{Type: *flLoggingDriver, Config: loggingOpts},

+		CgroupParent:   *flCgroupParent,

+		VolumeDriver:   *flVolumeDriver,

+		Isolation:      IsolationLevel(*flIsolation),

 	}

 	// When allocating stdin in attached mode, close stdin at client disconnect