kubeadm: Allow mixing Init and Join Configurations

cmd/kubeadm/app/util/config/common.go

@@ -93,19 +93,19 @@ func DetectUnsupportedVersion(b []byte) error {
 		}
 		knownKinds[gvk.Kind] = true
 	}
-	// InitConfiguration, MasterConfiguration and NodeConfiguration are mutually exclusive, error if more than one are specified
+
+	// InitConfiguration and JoinConfiguration may not apply together, warn if more than one is specified
 	mutuallyExclusive := []string{constants.InitConfigurationKind, constants.JoinConfigurationKind}
-	foundOne := false
+	mutuallyExclusiveCount := 0
 	for _, kind := range mutuallyExclusive {
 		if knownKinds[kind] {
-			if !foundOne {
-				foundOne = true
-				continue
-			}
-
-			return fmt.Errorf("invalid configuration: kinds %v are mutually exclusive", mutuallyExclusive)
+			mutuallyExclusiveCount++
 		}
 	}
+	if mutuallyExclusiveCount > 1 {
+		glog.Warningf("WARNING: Detected resource kinds that may not apply: %v", mutuallyExclusive)
+	}
+
 	return nil
 }
 

cmd/kubeadm/app/util/config/common_test.go

@@ -163,25 +163,27 @@ func TestDetectUnsupportedVersion(t *testing.T) {
 			name:         "Ignore other Kind",
 			fileContents: bytes.Join([][]byte{files["Foo"], files["Master_v1beta1"]}, []byte(constants.YAMLDocumentSeparator)),
 		},
+		// CanMixInitJoin cases used to be MustNotMixInitJoin, however due to UX issues DetectUnsupportedVersion had to tolerate that.
+		// So the following tests actually verify, that Init and Join can be mixed together with no error.
 		{
-			name:         "MustNotMixInitJoin v1alpha3",
+			name:         "CanMixInitJoin v1alpha3",
 			fileContents: bytes.Join([][]byte{files["Init_v1alpha3"], files["Join_v1alpha3"]}, []byte(constants.YAMLDocumentSeparator)),
-			expectedErr:  true,
+			expectedErr:  false,
 		},
 		{
-			name:         "MustNotMixInitJoin v1alpha3 - v1beta1",
+			name:         "CanMixInitJoin v1alpha3 - v1beta1",
 			fileContents: bytes.Join([][]byte{files["Init_v1alpha3"], files["Join_v1beta1"]}, []byte(constants.YAMLDocumentSeparator)),
-			expectedErr:  true,
+			expectedErr:  false,
 		},
 		{
-			name:         "MustNotMixInitJoin v1beta1 - v1alpha3",
+			name:         "CanMixInitJoin v1beta1 - v1alpha3",
 			fileContents: bytes.Join([][]byte{files["Init_v1beta1"], files["Join_v1alpha3"]}, []byte(constants.YAMLDocumentSeparator)),
-			expectedErr:  true,
+			expectedErr:  false,
 		},
 		{
-			name:         "MustNotMixInitJoin v1beta1",
+			name:         "CanMixInitJoin v1beta1",
 			fileContents: bytes.Join([][]byte{files["Init_v1beta1"], files["Join_v1beta1"]}, []byte(constants.YAMLDocumentSeparator)),
-			expectedErr:  true,
+			expectedErr:  false,
 		},
 	}
 

cmd/kubeadm/app/util/config/nodeconfig.go

@@ -19,6 +19,7 @@ package config
 import (
 	"fmt"
 	"io/ioutil"
+	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 
 	"github.com/golang/glog"
 
@@ -27,6 +28,7 @@ import (
 	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
 	kubeadmapiv1beta1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1"
 	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
+	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 )
 
 // SetJoinDynamicDefaults checks and sets configuration values for the JoinConfiguration object
@@ -61,7 +63,23 @@ func NodeConfigFileAndDefaultsToInternalConfig(cfgPath string, defaultversionedc
 			return nil, err
 		}
 
-		if err := runtime.DecodeInto(kubeadmscheme.Codecs.UniversalDecoder(), b, internalcfg); err != nil {
+		gvkmap, err := kubeadmutil.SplitYAMLDocuments(b)
+		if err != nil {
+			return nil, err
+		}
+
+		joinBytes := []byte{}
+		for gvk, bytes := range gvkmap {
+			if gvk.Kind == constants.JoinConfigurationKind {
+				joinBytes = bytes
+			}
+		}
+
+		if len(joinBytes) == 0 {
+			return nil, fmt.Errorf("no %s found in config file %q", constants.JoinConfigurationKind, cfgPath)
+		}
+
+		if err := runtime.DecodeInto(kubeadmscheme.Codecs.UniversalDecoder(), joinBytes, internalcfg); err != nil {
 			return nil, err
 		}
 	} else {