diff --git a/cmd/kubeadm/app/cmd/config.go b/cmd/kubeadm/app/cmd/config.go
index d747eea903..b846d2eb33 100644
--- a/cmd/kubeadm/app/cmd/config.go
+++ b/cmd/kubeadm/app/cmd/config.go
@@ -246,7 +246,10 @@ func NewCmdConfigMigrate(out io.Writer) *cobra.Command {
 				kubeadmutil.CheckErr(errors.New("The --old-config flag is mandatory"))
 			}
 
-			outputBytes, err := configutil.MigrateOldConfigFromFile(oldCfgPath)
+			oldCfgBytes, err := ioutil.ReadFile(oldCfgPath)
+			kubeadmutil.CheckErr(err)
+
+			outputBytes, err := configutil.MigrateOldConfig(oldCfgBytes)
 			kubeadmutil.CheckErr(err)
 
 			if newCfgPath == "" {
diff --git a/cmd/kubeadm/app/phases/upgrade/BUILD b/cmd/kubeadm/app/phases/upgrade/BUILD
index ffaae1e84c..484a6a0465 100644
--- a/cmd/kubeadm/app/phases/upgrade/BUILD
+++ b/cmd/kubeadm/app/phases/upgrade/BUILD
@@ -76,7 +76,6 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//cmd/kubeadm/app/apis/kubeadm:go_default_library",
-        "//cmd/kubeadm/app/apis/kubeadm/validation:go_default_library",
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/phases/certs:go_default_library",
         "//cmd/kubeadm/app/phases/controlplane:go_default_library",
diff --git a/cmd/kubeadm/app/phases/upgrade/staticpods_test.go b/cmd/kubeadm/app/phases/upgrade/staticpods_test.go
index 5689814e2a..b98b2b9a65 100644
--- a/cmd/kubeadm/app/phases/upgrade/staticpods_test.go
+++ b/cmd/kubeadm/app/phases/upgrade/staticpods_test.go
@@ -32,7 +32,6 @@ import (
 	"github.com/pkg/errors"
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
-	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	certsphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/certs"
 	controlplanephase "k8s.io/kubernetes/cmd/kubeadm/app/phases/controlplane"
@@ -541,22 +540,7 @@ func getConfig(version, certsDir, etcdDataDir string) (*kubeadmapi.InitConfigura
 	configBytes := []byte(fmt.Sprintf(testConfiguration, certsDir, etcdDataDir, version))
 
 	// Unmarshal the config
-	cfg, err := configutil.BytesToInternalConfig(configBytes)
-	if err != nil {
-		return nil, err
-	}
-
-	// Applies dynamic defaults to settings not provided with flags
-	if err = configutil.SetInitDynamicDefaults(cfg); err != nil {
-		return nil, err
-	}
-
-	// Validates cfg (flags/configs + defaults + dynamic defaults)
-	if err = validation.ValidateInitConfiguration(cfg).ToAggregate(); err != nil {
-		return nil, err
-	}
-
-	return cfg, nil
+	return configutil.BytesToInitConfiguration(configBytes)
 }
 
 func getTempDir(t *testing.T, name string) (string, func()) {
diff --git a/cmd/kubeadm/app/util/config/common.go b/cmd/kubeadm/app/util/config/common.go
index 7311b04f28..c782f6e7e0 100644
--- a/cmd/kubeadm/app/util/config/common.go
+++ b/cmd/kubeadm/app/util/config/common.go
@@ -18,7 +18,6 @@ package config
 
 import (
 	"bytes"
-	"io/ioutil"
 	"net"
 	"reflect"
 	"strings"
@@ -138,23 +137,24 @@ func ChooseAPIServerBindAddress(bindAddress net.IP) (net.IP, error) {
 	return ip, nil
 }
 
-// MigrateOldConfigFromFile migrates an old configuration from a file into a new one (returned as a byte slice). Only kubeadm kinds are migrated. Others are silently ignored.
-func MigrateOldConfigFromFile(cfgPath string) ([]byte, error) {
+// MigrateOldConfig migrates an old configuration from a byte slice into a new one (returned again as a byte slice).
+// Only kubeadm kinds are migrated. Others are silently ignored.
+func MigrateOldConfig(oldConfig []byte) ([]byte, error) {
 	newConfig := [][]byte{}
 
-	cfgBytes, err := ioutil.ReadFile(cfgPath)
+	gvkmap, err := kubeadmutil.SplitYAMLDocuments(oldConfig)
 	if err != nil {
 		return []byte{}, err
 	}
 
-	gvks, err := kubeadmutil.GroupVersionKindsFromBytes(cfgBytes)
-	if err != nil {
-		return []byte{}, err
+	gvks := []schema.GroupVersionKind{}
+	for gvk := range gvkmap {
+		gvks = append(gvks, gvk)
 	}
 
 	// Migrate InitConfiguration and ClusterConfiguration if there are any in the config
 	if kubeadmutil.GroupVersionKindsHasInitConfiguration(gvks...) || kubeadmutil.GroupVersionKindsHasClusterConfiguration(gvks...) {
-		o, err := LoadInitConfigurationFromFile(cfgPath)
+		o, err := documentMapToInitConfiguration(gvkmap)
 		if err != nil {
 			return []byte{}, err
 		}
@@ -167,7 +167,7 @@ func MigrateOldConfigFromFile(cfgPath string) ([]byte, error) {
 
 	// Migrate JoinConfiguration if there is any
 	if kubeadmutil.GroupVersionKindsHasJoinConfiguration(gvks...) {
-		o, err := LoadJoinConfigurationFromFile(cfgPath)
+		o, err := documentMapToJoinConfiguration(gvkmap)
 		if err != nil {
 			return []byte{}, err
 		}
diff --git a/cmd/kubeadm/app/util/config/common_test.go b/cmd/kubeadm/app/util/config/common_test.go
index e0d18dda99..c2cff8b366 100644
--- a/cmd/kubeadm/app/util/config/common_test.go
+++ b/cmd/kubeadm/app/util/config/common_test.go
@@ -17,8 +17,6 @@ limitations under the License.
 package config
 
 import (
-	"io/ioutil"
-	"os"
 	"testing"
 
 	"github.com/lithammer/dedent"
@@ -352,20 +350,7 @@ func TestMigrateOldConfigFromFile(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.desc, func(t *testing.T) {
-			file, err := ioutil.TempFile("", "")
-			if err != nil {
-				t.Fatalf("could not create temporary test file: %v", err)
-			}
-			fileName := file.Name()
-			defer os.Remove(fileName)
-
-			_, err = file.WriteString(test.oldCfg)
-			file.Close()
-			if err != nil {
-				t.Fatalf("could not write contents of old config: %v", err)
-			}
-
-			b, err := MigrateOldConfigFromFile(fileName)
+			b, err := MigrateOldConfig([]byte(test.oldCfg))
 			if test.expectErr {
 				if err == nil {
 					t.Fatalf("unexpected success:\n%s", b)
diff --git a/cmd/kubeadm/app/util/config/initconfiguration.go b/cmd/kubeadm/app/util/config/initconfiguration.go
index 197467ecd1..e21ecac017 100644
--- a/cmd/kubeadm/app/util/config/initconfiguration.go
+++ b/cmd/kubeadm/app/util/config/initconfiguration.go
@@ -190,19 +190,10 @@ func LoadInitConfigurationFromFile(cfgPath string) (*kubeadmapi.InitConfiguratio
 		return nil, errors.Wrapf(err, "unable to read config from %q ", cfgPath)
 	}
 
-	internalcfg, err := BytesToInternalConfig(b)
+	internalcfg, err := BytesToInitConfiguration(b)
 	if err != nil {
 		return nil, err
 	}
-
-	// Applies dynamic defaults to settings not provided with flags
-	if err := SetInitDynamicDefaults(internalcfg); err != nil {
-		return nil, err
-	}
-	// Validates cfg (flags/configs + defaults + dynamic defaults)
-	if err := validation.ValidateInitConfiguration(internalcfg).ToAggregate(); err != nil {
-		return nil, err
-	}
 	return internalcfg, nil
 }
 
@@ -221,19 +212,25 @@ func LoadOrDefaultInitConfiguration(cfgPath string, defaultversionedcfg *kubeadm
 	return DefaultedInitConfiguration(defaultversionedcfg)
 }
 
-// BytesToInternalConfig converts a byte slice to an internal, defaulted and validated configuration object.
-// The byte slice may contain one or many different YAML documents. These YAML documents are parsed one-by-one
-// and well-known ComponentConfig GroupVersionKinds are stored inside of the internal InitConfiguration struct
-func BytesToInternalConfig(b []byte) (*kubeadmapi.InitConfiguration, error) {
-	var initcfg *kubeadmapi.InitConfiguration
-	var clustercfg *kubeadmapi.ClusterConfiguration
-	decodedComponentConfigObjects := map[componentconfigs.RegistrationKind]runtime.Object{}
-
+// BytesToInitConfiguration converts a byte slice to an internal, defaulted and validated InitConfiguration object.
+// The map may contain many different YAML documents. These YAML documents are parsed one-by-one
+// and well-known ComponentConfig GroupVersionKinds are stored inside of the internal InitConfiguration struct.
+// The resulting InitConfiguration is then dynamically defaulted and validated prior to return.
+func BytesToInitConfiguration(b []byte) (*kubeadmapi.InitConfiguration, error) {
 	gvkmap, err := kubeadmutil.SplitYAMLDocuments(b)
 	if err != nil {
 		return nil, err
 	}
 
+	return documentMapToInitConfiguration(gvkmap)
+}
+
+// documentMapToInitConfiguration converts a map of GVKs and YAML documents to defaulted and validated configuration object.
+func documentMapToInitConfiguration(gvkmap map[schema.GroupVersionKind][]byte) (*kubeadmapi.InitConfiguration, error) {
+	var initcfg *kubeadmapi.InitConfiguration
+	var clustercfg *kubeadmapi.ClusterConfiguration
+	decodedComponentConfigObjects := map[componentconfigs.RegistrationKind]runtime.Object{}
+
 	for gvk, fileContent := range gvkmap {
 		// first, check if this GVK is supported one
 		if err := ValidateSupportedVersion(gvk.GroupVersion()); err != nil {
@@ -308,6 +305,17 @@ func BytesToInternalConfig(b []byte) (*kubeadmapi.InitConfiguration, error) {
 			fmt.Printf("[config] WARNING: Decoded a kind that couldn't be saved to the internal configuration: %q\n", string(kind))
 		}
 	}
+
+	// Applies dynamic defaults to settings not provided with flags
+	if err := SetInitDynamicDefaults(initcfg); err != nil {
+		return nil, err
+	}
+
+	// Validates cfg (flags/configs + defaults + dynamic defaults)
+	if err := validation.ValidateInitConfiguration(initcfg).ToAggregate(); err != nil {
+		return nil, err
+	}
+
 	return initcfg, nil
 }
 
diff --git a/cmd/kubeadm/app/util/config/joinconfiguration.go b/cmd/kubeadm/app/util/config/joinconfiguration.go
index d512424e86..f328876d2a 100644
--- a/cmd/kubeadm/app/util/config/joinconfiguration.go
+++ b/cmd/kubeadm/app/util/config/joinconfiguration.go
@@ -21,6 +21,7 @@ import (
 
 	"github.com/pkg/errors"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/klog"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
@@ -83,6 +84,12 @@ func LoadJoinConfigurationFromFile(cfgPath string) (*kubeadmapi.JoinConfiguratio
 		return nil, err
 	}
 
+	return documentMapToJoinConfiguration(gvkmap)
+}
+
+// documentMapToJoinConfiguration takes a map between GVKs and YAML documents (as returned by SplitYAMLDocuments),
+// finds a JoinConfiguration, decodes it, dynamically defaults it and then validates it prior to return.
+func documentMapToJoinConfiguration(gvkmap map[schema.GroupVersionKind][]byte) (*kubeadmapi.JoinConfiguration, error) {
 	joinBytes := []byte{}
 	for gvk, bytes := range gvkmap {
 		// not interested in anything other than JoinConfiguration
@@ -102,7 +109,7 @@ func LoadJoinConfigurationFromFile(cfgPath string) (*kubeadmapi.JoinConfiguratio
 	}
 
 	if len(joinBytes) == 0 {
-		return nil, errors.Errorf("no %s found in config file %q", constants.JoinConfigurationKind, cfgPath)
+		return nil, errors.Errorf("no %s found in the supplied config", constants.JoinConfigurationKind)
 	}
 
 	internalcfg := &kubeadmapi.JoinConfiguration{}