@@ -92,6 +92,8 @@ func installRegistryServiceFlags(options *registry.ServiceOptions, flags *pflag.

 	flags.Var(insecureRegistries, "insecure-registry", "Enable insecure registry communication")

 	if runtime.GOOS != "windows" {

+		// TODO: Remove this flag after 3 release cycles (18.03)

 		flags.BoolVar(&options.V2Only, "disable-legacy-registry", true, "Disable contacting legacy registries")

+		flags.MarkHidden("disable-legacy-registry")

 	}

 }

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

 	"fmt"

 	"os"

 	"path/filepath"

+	"runtime"

 	"strings"

 	"time"

@@ -472,8 +473,15 @@ func loadDaemonCliConfig(opts *daemonOptions) (*config.Config, error) {

 		return nil, err

 	}

-	if !conf.V2Only {

-		logrus.Warnf(`The "disable-legacy-registry" option is deprecated and wil be removed in Docker v17.12. Interacting with legacy (v1) registries will no longer be supported in Docker v17.12"`)

+	if runtime.GOOS != "windows" {

+		if flags.Changed("disable-legacy-registry") {

+			// TODO: Remove this error after 3 release cycles (18.03)

+			return nil, errors.New("ERROR: The '--disable-legacy-registry' flag has been removed. Interacting with legacy (v1) registries is no longer supported")

+		}

+		if !conf.V2Only {

+			// TODO: Remove this error after 3 release cycles (18.03)

+			return nil, errors.New("ERROR: The 'disable-legacy-registry' configuration option has been removed. Interacting with legacy (v1) registries is no longer supported")

+		}

 	}

 	if flags.Changed("graph") {

@@ -97,15 +97,3 @@ func TestLoadDaemonConfigWithTrueDefaultValuesLeaveDefaults(t *testing.T) {

 	assert.True(t, loadedConfig.EnableUserlandProxy)

 }

-

-func TestLoadDaemonConfigWithLegacyRegistryOptions(t *testing.T) {

-	content := `{"disable-legacy-registry": false}`

-	tempFile := fs.NewFile(t, "config", fs.WithContent(content))

-	defer tempFile.Remove()

-

-	opts := defaultOptions(tempFile.Path())

-	loadedConfig, err := loadDaemonCliConfig(opts)

-	require.NoError(t, err)

-	require.NotNil(t, loadedConfig)

-	assert.False(t, loadedConfig.V2Only)

-}

@@ -13,9 +13,7 @@ import (

 )

 func (s *DockerRegistryAuthHtpasswdSuite) TestLogoutWithExternalAuth(c *check.C) {

-

-	// @TODO TestLogoutWithExternalAuth expects docker to fall back to a v1 registry, so has to be updated for v17.12, when v1 registries are no longer supported

-	s.d.StartWithBusybox(c, "--disable-legacy-registry=false")

+	s.d.StartWithBusybox(c)

 	osPath := os.Getenv("PATH")

 	defer os.Setenv("PATH", osPath)

@@ -62,7 +60,7 @@ func (s *DockerRegistryAuthHtpasswdSuite) TestLogoutWithExternalAuth(c *check.C)

 	// check I cannot pull anymore

 	out, err := s.d.Cmd("--config", tmp, "pull", repoName)

 	c.Assert(err, check.NotNil, check.Commentf(out))

-	c.Assert(out, checker.Contains, "Error: image dockercli/busybox:authtest not found")

+	c.Assert(out, checker.Contains, "no basic auth credentials")

 }

 // #23100

@@ -259,18 +259,6 @@ func (s *DockerHubPullSuite) TestPullClientDisconnect(c *check.C) {

 	c.Assert(err, checker.NotNil, check.Commentf("image was pulled after client disconnected"))

 }

-func (s *DockerRegistryAuthHtpasswdSuite) TestPullNoCredentialsNotFound(c *check.C) {

-	// @TODO TestPullNoCredentialsNotFound expects docker to fall back to a v1 registry, so has to be updated for v17.12, when v1 registries are no longer supported

-	s.d.StartWithBusybox(c, "--disable-legacy-registry=false")

-

-	// we don't care about the actual image, we just want to see image not found

-	// because that means v2 call returned 401 and we fell back to v1 which usually

-	// gives a 404 (in this case the test registry doesn't handle v1 at all)

-	out, err := s.d.Cmd("pull", privateRegistryURL+"/busybox")

-	c.Assert(err, check.NotNil, check.Commentf(out))

-	c.Assert(out, checker.Contains, "Error: image busybox:latest not found")

-}

-

 // Regression test for https://github.com/docker/docker/issues/26429

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

 	testRequires(c, DaemonIsWindows, Network)

@@ -22,7 +22,7 @@ func makefile(path string, contents string) (string, error) {

 	return f.Name(), nil

 }

-// TestV2Only ensures that a daemon by default does not

+// TestV2Only ensures that a daemon does not

 // attempt to contact any v1 registry endpoints.

 func (s *DockerRegistrySuite) TestV2Only(c *check.C) {

 	reg, err := registry.NewMock(c)

@@ -56,65 +56,3 @@ func (s *DockerRegistrySuite) TestV2Only(c *check.C) {

 	s.d.Cmd("push", repoName)

 	s.d.Cmd("pull", repoName)

 }

-

-// TestV1 starts a daemon with legacy registries enabled

-// and ensure v1 endpoints are hit for the following operations:

-// login, push, pull, build & run

-func (s *DockerRegistrySuite) TestV1(c *check.C) {

-	reg, err := registry.NewMock(c)

-	defer reg.Close()

-	c.Assert(err, check.IsNil)

-

-	v2Pings := 0

-	reg.RegisterHandler("/v2/", func(w http.ResponseWriter, r *http.Request) {

-		v2Pings++

-		// V2 ping 404 causes fallback to v1

-		w.WriteHeader(404)

-	})

-

-	v1Pings := 0

-	reg.RegisterHandler("/v1/_ping", func(w http.ResponseWriter, r *http.Request) {

-		v1Pings++

-	})

-

-	v1Logins := 0

-	reg.RegisterHandler("/v1/users/", func(w http.ResponseWriter, r *http.Request) {

-		v1Logins++

-	})

-

-	v1Repo := 0

-	reg.RegisterHandler("/v1/repositories/busybox/", func(w http.ResponseWriter, r *http.Request) {

-		v1Repo++

-	})

-

-	reg.RegisterHandler("/v1/repositories/busybox/images", func(w http.ResponseWriter, r *http.Request) {

-		v1Repo++

-	})

-

-	s.d.Start(c, "--insecure-registry", reg.URL(), "--disable-legacy-registry=false")

-

-	tmp, err := ioutil.TempDir("", "integration-cli-")

-	c.Assert(err, check.IsNil)

-	defer os.RemoveAll(tmp)

-

-	dockerfileName, err := makefile(tmp, fmt.Sprintf("FROM %s/busybox", reg.URL()))

-	c.Assert(err, check.IsNil, check.Commentf("Unable to create test dockerfile"))

-

-	s.d.Cmd("build", "--file", dockerfileName, tmp)

-	c.Assert(v1Repo, check.Equals, 1, check.Commentf("Expected v1 repository access after build"))

-

-	repoName := fmt.Sprintf("%s/busybox", reg.URL())

-	s.d.Cmd("run", repoName)

-	c.Assert(v1Repo, check.Equals, 2, check.Commentf("Expected v1 repository access after run"))

-

-	s.d.Cmd("login", "-u", "richard", "-p", "testtest", reg.URL())

-	c.Assert(v1Logins, check.Equals, 1, check.Commentf("Expected v1 login attempt"))

-

-	s.d.Cmd("tag", "busybox", repoName)

-	s.d.Cmd("push", repoName)

-

-	c.Assert(v1Repo, check.Equals, 2)

-

-	s.d.Cmd("pull", repoName)

-	c.Assert(v1Repo, check.Equals, 3, check.Commentf("Expected v1 repository access after pull"))

-}