Use apimachinery for serialising kubeadm MasterConfiguration

this ensures configmaps have kind and versions in them

cmd/kubeadm/app/apis/kubeadm/scheme/scheme.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package scheme
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"
+)
+
+// Scheme is the runtime.Scheme to which all kubeadm api types are registered.
+var Scheme = runtime.NewScheme()
+
+// Codecs provides access to encoding and decoding for the scheme.
+var Codecs = serializer.NewCodecFactory(Scheme)
+
+func init() {
+	metav1.AddToGroupVersion(Scheme, schema.GroupVersion{Version: "v1"})
+	AddToScheme(Scheme)
+}
+
+// AddToScheme builds the Kubeadm scheme using all known versions of the kubeadm api.
+func AddToScheme(scheme *runtime.Scheme) {
+	v1alpha1.AddToScheme(scheme)
+}

cmd/kubeadm/app/phases/uploadconfig/uploadconfig.go

@@ -17,15 +17,16 @@ limitations under the License.
 package uploadconfig
 
 import (
-	"github.com/ghodss/yaml"
 	"github.com/golang/glog"
 
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	clientset "k8s.io/client-go/kubernetes"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
 	kubeadmapiext "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 )
@@ -42,7 +43,7 @@ func UploadConfiguration(cfg *kubeadmapi.MasterConfiguration, client clientset.I
 	// Removes sensitive info from the data that will be stored in the config map
 	externalcfg.Token = ""
 
-	cfgYaml, err := yaml.Marshal(*externalcfg)
+	cfgYaml, err := util.MarshalToYamlForCodecs(externalcfg, kubeadmapiext.SchemeGroupVersion, scheme.Codecs)
 	if err != nil {
 		return err
 	}

cmd/kubeadm/app/phases/uploadconfig/uploadconfig_test.go

@@ -113,6 +113,14 @@ func TestUploadConfiguration(t *testing.T) {
 				if decodedCfg.Token != "" {
 					t.Errorf("Decoded value contains token (sensitive info), decoded = %#v, expected = empty", decodedCfg.Token)
 				}
+
+				if decodedExtCfg.Kind != "MasterConfiguration" {
+					t.Errorf("Expected kind MasterConfiguration, got %v", decodedExtCfg.Kind)
+				}
+
+				if decodedExtCfg.APIVersion != "kubeadm.k8s.io/v1alpha1" {
+					t.Errorf("Expected apiVersion kubeadm.k8s.io/v1alpha1, got %v", decodedExtCfg.APIVersion)
+				}
 			}
 		})
 	}