From f0d82fb5f453d6fc1fd7d9f514237583ae898105 Mon Sep 17 00:00:00 2001
From: "Rostislav M. Georgiev" <rostislavg@vmware.com>
Date: Thu, 4 Oct 2018 15:54:29 +0300
Subject: [PATCH] kubeadm: Allow mixing Init and Join Configurations

This change allows mixing InitConfiguration/ClusterConfiguration with
JoinConfiguration in a single YAML file, by performing the following changes:

- Replace the explicit error in `DetectUnsupportedVersion` with a warning.
- Modify `NodeConfigFileAndDefaultsToInternalConfig` to use only
  `JoinConfiguration`.

Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>
---
 cmd/kubeadm/app/util/config/common.go      | 16 ++++++++--------
 cmd/kubeadm/app/util/config/common_test.go | 18 ++++++++++--------
 cmd/kubeadm/app/util/config/nodeconfig.go  | 20 +++++++++++++++++++-
 3 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/cmd/kubeadm/app/util/config/common.go b/cmd/kubeadm/app/util/config/common.go
index b55d0d8a4ed..63a5ab57778 100644
--- a/cmd/kubeadm/app/util/config/common.go
+++ b/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
 }
 
diff --git a/cmd/kubeadm/app/util/config/common_test.go b/cmd/kubeadm/app/util/config/common_test.go
index bc4ecf60932..358cc483984 100644
--- a/cmd/kubeadm/app/util/config/common_test.go
+++ b/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,
 		},
 	}
 
diff --git a/cmd/kubeadm/app/util/config/nodeconfig.go b/cmd/kubeadm/app/util/config/nodeconfig.go
index e161be5adbe..f10cf6fea64 100644
--- a/cmd/kubeadm/app/util/config/nodeconfig.go
+++ b/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 {