@@ -59,6 +59,8 @@ func installCommonConfigFlags(conf *config.Config, flags *pflag.FlagSet) {

 	flags.IntVar(&maxConcurrentDownloads, "max-concurrent-downloads", config.DefaultMaxConcurrentDownloads, "Set the max concurrent downloads for each pull")

 	flags.IntVar(&maxConcurrentUploads, "max-concurrent-uploads", config.DefaultMaxConcurrentUploads, "Set the max concurrent uploads for each push")

 	flags.IntVar(&conf.ShutdownTimeout, "shutdown-timeout", defaultShutdownTimeout, "Set the default shutdown timeout")

+	flags.IntVar(&conf.NetworkDiagnosticPort, "network-diagnostic-port", 0, "TCP port number of the network diagnostic server")

+	flags.MarkHidden("network-diagnostic-port")

 	flags.StringVar(&conf.SwarmDefaultAdvertiseAddr, "swarm-default-advertise-addr", "", "Set default address or interface for swarm advertised address")

 	flags.BoolVar(&conf.Experimental, "experimental", false, "Enable experimental features")

@@ -85,26 +85,27 @@ type CommonTLSOptions struct {

 // It includes json tags to deserialize configuration from a file

 // using the same names that the flags in the command line use.

 type CommonConfig struct {

-	AuthzMiddleware      *authorization.Middleware `json:"-"`

-	AuthorizationPlugins []string                  `json:"authorization-plugins,omitempty"` // AuthorizationPlugins holds list of authorization plugins

-	AutoRestart          bool                      `json:"-"`

-	Context              map[string][]string       `json:"-"`

-	DisableBridge        bool                      `json:"-"`

-	DNS                  []string                  `json:"dns,omitempty"`

-	DNSOptions           []string                  `json:"dns-opts,omitempty"`

-	DNSSearch            []string                  `json:"dns-search,omitempty"`

-	ExecOptions          []string                  `json:"exec-opts,omitempty"`

-	GraphDriver          string                    `json:"storage-driver,omitempty"`

-	GraphOptions         []string                  `json:"storage-opts,omitempty"`

-	Labels               []string                  `json:"labels,omitempty"`

-	Mtu                  int                       `json:"mtu,omitempty"`

-	Pidfile              string                    `json:"pidfile,omitempty"`

-	RawLogs              bool                      `json:"raw-logs,omitempty"`

-	RootDeprecated       string                    `json:"graph,omitempty"`

-	Root                 string                    `json:"data-root,omitempty"`

-	ExecRoot             string                    `json:"exec-root,omitempty"`

-	SocketGroup          string                    `json:"group,omitempty"`

-	CorsHeaders          string                    `json:"api-cors-header,omitempty"`

+	AuthzMiddleware       *authorization.Middleware `json:"-"`

+	AuthorizationPlugins  []string                  `json:"authorization-plugins,omitempty"` // AuthorizationPlugins holds list of authorization plugins

+	AutoRestart           bool                      `json:"-"`

+	Context               map[string][]string       `json:"-"`

+	DisableBridge         bool                      `json:"-"`

+	DNS                   []string                  `json:"dns,omitempty"`

+	DNSOptions            []string                  `json:"dns-opts,omitempty"`

+	DNSSearch             []string                  `json:"dns-search,omitempty"`

+	ExecOptions           []string                  `json:"exec-opts,omitempty"`

+	GraphDriver           string                    `json:"storage-driver,omitempty"`

+	GraphOptions          []string                  `json:"storage-opts,omitempty"`

+	Labels                []string                  `json:"labels,omitempty"`

+	Mtu                   int                       `json:"mtu,omitempty"`

+	NetworkDiagnosticPort int                       `json:"network-diagnostic-port,omitempty"`

+	Pidfile               string                    `json:"pidfile,omitempty"`

+	RawLogs               bool                      `json:"raw-logs,omitempty"`

+	RootDeprecated        string                    `json:"graph,omitempty"`

+	Root                  string                    `json:"data-root,omitempty"`

+	ExecRoot              string                    `json:"exec-root,omitempty"`

+	SocketGroup           string                    `json:"group,omitempty"`

+	CorsHeaders           string                    `json:"api-cors-header,omitempty"`

 	// TrustKeyPath is used to generate the daemon ID and for signing schema 1 manifests

 	// when pushing to a registry which does not support schema 2. This field is marked as

@@ -61,6 +61,9 @@ func (daemon *Daemon) Reload(conf *config.Config) (err error) {

 	if err := daemon.reloadLiveRestore(conf, attributes); err != nil {

 		return err

 	}

+	if err := daemon.reloadNetworkDiagnosticPort(conf, attributes); err != nil {

+		return err

+	}

 	return nil

 }

@@ -308,3 +311,18 @@ func (daemon *Daemon) reloadLiveRestore(conf *config.Config, attributes map[stri

 	attributes["live-restore"] = fmt.Sprintf("%t", daemon.configStore.LiveRestoreEnabled)

 	return nil

 }

+

+// reloadNetworkDiagnosticPort updates the network controller starting the diagnose mode if the config is valid

+func (daemon *Daemon) reloadNetworkDiagnosticPort(conf *config.Config, attributes map[string]string) error {

+	if conf == nil || daemon.netController == nil {

+		return nil

+	}

+	// Enable the network diagnose if the flag is set with a valid port withing the range

+	if conf.IsValueSet("network-diagnostic-port") && conf.NetworkDiagnosticPort > 0 && conf.NetworkDiagnosticPort < 65536 {

+		logrus.Warnf("Calling the diagnostic start with %d", conf.NetworkDiagnosticPort)

+		daemon.netController.StartDiagnose(conf.NetworkDiagnosticPort)

+	} else {

+		daemon.netController.StopDiagnose()

+	}

+	return nil

+}

@@ -10,6 +10,7 @@ import (

 	"github.com/docker/docker/pkg/discovery"

 	_ "github.com/docker/docker/pkg/discovery/memory"

 	"github.com/docker/docker/registry"

+	"github.com/docker/libnetwork"

 	"github.com/stretchr/testify/assert"

 )

@@ -479,3 +480,71 @@ func TestDaemonDiscoveryReloadOnlyClusterAdvertise(t *testing.T) {

 		t.Fatal(e)

 	}

 }

+

+func TestDaemonReloadNetworkDiagnosticPort(t *testing.T) {

+	daemon := &Daemon{}

+	daemon.configStore = &config.Config{}

+

+	valuesSet := make(map[string]interface{})

+	valuesSet["network-diagnostic-port"] = 2000

+	enableConfig := &config.Config{

+		CommonConfig: config.CommonConfig{

+			NetworkDiagnosticPort: 2000,

+			ValuesSet:             valuesSet,

+		},

+	}

+	disableConfig := &config.Config{

+		CommonConfig: config.CommonConfig{},

+	}

+

+	netOptions, err := daemon.networkOptions(enableConfig, nil, nil)

+	if err != nil {

+		t.Fatal(err)

+	}

+	controller, err := libnetwork.New(netOptions...)

+	if err != nil {

+		t.Fatal(err)

+	}

+	daemon.netController = controller

+

+	// Enable/Disable the server for some iterations

+	for i := 0; i < 10; i++ {

+		enableConfig.CommonConfig.NetworkDiagnosticPort++

+		if err := daemon.Reload(enableConfig); err != nil {

+			t.Fatal(err)

+		}

+		// Check that the diagnose is enabled

+		if !daemon.netController.IsDiagnoseEnabled() {

+			t.Fatalf("diagnosed should be enable")

+		}

+

+		// Reload

+		if err := daemon.Reload(disableConfig); err != nil {

+			t.Fatal(err)

+		}

+		// Check that the diagnose is disabled

+		if daemon.netController.IsDiagnoseEnabled() {

+			t.Fatalf("diagnosed should be disable")

+		}

+	}

+

+	enableConfig.CommonConfig.NetworkDiagnosticPort++

+	// 2 times the enable should not create problems

+	if err := daemon.Reload(enableConfig); err != nil {

+		t.Fatal(err)

+	}

+	// Check that the diagnose is enabled

+	if !daemon.netController.IsDiagnoseEnabled() {

+		t.Fatalf("diagnosed should be enable")

+	}

+

+	// Check that another reload does not cause issues

+	if err := daemon.Reload(enableConfig); err != nil {

+		t.Fatal(err)

+	}

+	// Check that the diagnose is enable

+	if !daemon.netController.IsDiagnoseEnabled() {

+		t.Fatalf("diagnosed should be enable")

+	}

+

+}