kubeadm: fix panic when no UpgradeConfiguration was found in the config file

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

@@ -492,13 +492,3 @@ func defaultEmptyMigrateMutators() migrateMutators {
 
 	return *mutators
 }
-
-// isKubeadmConfigPresent checks if a kubeadm config type is found in the provided document map
-func isKubeadmConfigPresent(docmap kubeadmapi.DocumentMap) bool {
-	for gvk := range docmap {
-		if gvk.Group == kubeadmapi.GroupName {
-			return true
-		}
-	}
-	return false
-}

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

@@ -972,52 +972,3 @@ func TestDefaultMigrateMutators(t *testing.T) {
 		})
 	}
 }
-
-func TestIsKubeadmConfigPresent(t *testing.T) {
-	var tcases = []struct {
-		name     string
-		gvkmap   kubeadmapi.DocumentMap
-		expected bool
-	}{
-		{
-			name: " Wrong Group value",
-			gvkmap: kubeadmapi.DocumentMap{
-				{Group: "foo.k8s.io", Version: "v1", Kind: "Foo"}: []byte(`kind: Foo`),
-			},
-			expected: false,
-		},
-		{
-			name: "Empty Group value",
-			gvkmap: kubeadmapi.DocumentMap{
-				{Group: "", Version: "v1", Kind: "Empty"}: []byte(`kind: Empty`),
-			},
-			expected: false,
-		},
-		{
-			name:     "Nil value",
-			gvkmap:   nil,
-			expected: false,
-		},
-		{
-			name: "Correct Group value 1",
-			gvkmap: kubeadmapi.DocumentMap{
-				{Group: "kubeadm.k8s.io", Version: "v1", Kind: "Empty"}: []byte(`kind: Empty`),
-			},
-			expected: true,
-		},
-		{
-			name: "Correct Group value 2",
-			gvkmap: kubeadmapi.DocumentMap{
-				{Group: kubeadmapi.GroupName, Version: "v1", Kind: "Empty"}: []byte(`kind: Empty`),
-			},
-			expected: true,
-		},
-	}
-	for _, tt := range tcases {
-		t.Run(tt.name, func(t *testing.T) {
-			if isKubeadmConfigPresent(tt.gvkmap) != tt.expected {
-				t.Error("unexpected result")
-			}
-		})
-	}
-}

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

@@ -22,28 +22,34 @@ import (
 	"github.com/pkg/errors"
 
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/klog/v2"
-	kubeproxyconfig "k8s.io/kube-proxy/config/v1alpha1"
-	kubeletconfig "k8s.io/kubelet/config/v1beta1"
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta4"
 	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
 	"k8s.io/kubernetes/cmd/kubeadm/app/componentconfigs"
+	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/config/strict"
 )
 
-var componentCfgGV = sets.New(kubeproxyconfig.GroupName, kubeletconfig.GroupName)
-
 // documentMapToUpgradeConfiguration takes a map between GVKs and YAML documents (as returned by SplitYAMLDocuments),
 // finds a UpgradeConfiguration, decodes it, dynamically defaults it and then validates it prior to return.
 func documentMapToUpgradeConfiguration(gvkmap kubeadmapi.DocumentMap, allowDeprecated bool) (*kubeadmapi.UpgradeConfiguration, error) {
-	var internalcfg *kubeadmapi.UpgradeConfiguration
+	upgradeBytes := []byte{}
 
 	for gvk, bytes := range gvkmap {
+		if kubeadmutil.GroupVersionKindsHasInitConfiguration(gvk) || kubeadmutil.GroupVersionKindsHasClusterConfiguration(gvk) || componentconfigs.Scheme.IsGroupRegistered(gvk.Group) {
+			klog.Warningf("[config] WARNING: YAML document with GroupVersionKind %v is deprecated for upgrade, please use config file with kind of UpgradeConfiguration instead \n", gvk)
+			continue
+		}
+
+		if gvk.Kind != constants.UpgradeConfigurationKind {
+			klog.Warningf("[config] WARNING: Ignored YAML document with GroupVersionKind %v\n", gvk)
+			continue
+		}
+
 		// check if this version is supported and possibly not deprecated
 		if err := validateSupportedVersion(gvk, allowDeprecated, true); err != nil {
 			return nil, err
@@ -54,37 +60,19 @@ func documentMapToUpgradeConfiguration(gvkmap kubeadmapi.DocumentMap, allowDepre
 			klog.Warning(err.Error())
 		}
 
-		if kubeadmutil.GroupVersionKindsHasInitConfiguration(gvk) || kubeadmutil.GroupVersionKindsHasClusterConfiguration(gvk) {
+		upgradeBytes = bytes
-			klog.Warningf("[config] WARNING: YAML document with GroupVersionKind %v is deprecated for upgrade, please use config file with kind of UpgradeConfiguration instead \n", gvk)
-			continue
-		}
-
-		if kubeadmutil.GroupVersionKindsHasUpgradeConfiguration(gvk) {
-			// Set internalcfg to an empty struct value the deserializer will populate
-			internalcfg = &kubeadmapi.UpgradeConfiguration{}
-			// Decode the bytes into the internal struct. Under the hood, the bytes will be unmarshalled into the
-			// right external version, defaulted, and converted into the internal version.
-			if err := runtime.DecodeInto(kubeadmscheme.Codecs.UniversalDecoder(), bytes, internalcfg); err != nil {
-				return nil, err
-			}
-			continue
-		}
-
-		// If the group is neither a kubeadm core type or of a supported component config group, we dump a warning about it being ignored
-		if !componentconfigs.Scheme.IsGroupRegistered(gvk.Group) {
-			klog.Warningf("[config] WARNING: Ignored YAML document with GroupVersionKind %v\n", gvk)
-		}
 	}
 
-	// If UpgradeConfiguration wasn't given, default it by creating an external struct instance, default it and convert into the internal type
+	if len(upgradeBytes) == 0 {
-	if internalcfg == nil {
+		return nil, errors.Errorf("no %s found in the supplied config", constants.UpgradeConfigurationKind)
-		extinitcfg := &kubeadmapiv1.UpgradeConfiguration{}
+	}
-		kubeadmscheme.Scheme.Default(extinitcfg)
+
-		// Set upgradeCfg to an empty struct value the deserializer will populate
+	// Set internalcfg to an empty struct value the deserializer will populate
-		internalcfg = &kubeadmapi.UpgradeConfiguration{}
+	internalcfg := &kubeadmapi.UpgradeConfiguration{}
-		if err := kubeadmscheme.Scheme.Convert(extinitcfg, internalcfg, nil); err != nil {
+	// Decode the bytes into the internal struct. Under the hood, the bytes will be unmarshalled into the
-			return nil, err
+	// right external version, defaulted, and converted into the internal version.
-		}
+	if err := runtime.DecodeInto(kubeadmscheme.Codecs.UniversalDecoder(), upgradeBytes, internalcfg); err != nil {
+		return nil, err
 	}
 
 	// Validates cfg
@@ -96,9 +84,6 @@ func documentMapToUpgradeConfiguration(gvkmap kubeadmapi.DocumentMap, allowDepre
 }
 
 // DocMapToUpgradeConfiguration converts documentMap to an internal, defaulted and validated UpgradeConfiguration 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 UpgradeConfiguration struct.
-// The resulting UpgradeConfiguration is then dynamically defaulted and validated prior to return.
 func DocMapToUpgradeConfiguration(gvkmap kubeadmapi.DocumentMap) (*kubeadmapi.UpgradeConfiguration, error) {
 	return documentMapToUpgradeConfiguration(gvkmap, false)
 }
@@ -123,18 +108,8 @@ func LoadUpgradeConfigurationFromFile(cfgPath string, _ LoadOrDefaultConfigurati
 	// Convert documentMap to internal UpgradeConfiguration, InitConfiguration and ClusterConfiguration from config file will be ignored.
 	// Upgrade should respect the cluster configuration from the existing cluster, re-configure the cluster with a InitConfiguration and
 	// ClusterConfiguration from the config file is not allowed for upgrade.
-	if isKubeadmConfigPresent(docmap) {
+	if upgradeCfg, err = DocMapToUpgradeConfiguration(docmap); err != nil {
-		if upgradeCfg, err = DocMapToUpgradeConfiguration(docmap); err != nil {
+		return nil, err
-			return nil, err
-		}
-	}
-
-	// Check is there any component configs defined in the config file.
-	for gvk := range docmap {
-		if componentCfgGV.Has(gvk.Group) {
-			klog.Warningf("[config] WARNING: YAML document with Component Configs %v is deprecated for upgrade and will be ignored \n", gvk.Group)
-			continue
-		}
 	}
 
 	return upgradeCfg, nil

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

@@ -38,9 +38,10 @@ import (
 
 func TestDocMapToUpgradeConfiguration(t *testing.T) {
 	tests := []struct {
-		name        string
+		name          string
-		cfg         kubeadmapiv1.UpgradeConfiguration
+		cfg           interface{}
-		expectedCfg kubeadmapi.UpgradeConfiguration
+		expectedCfg   kubeadmapi.UpgradeConfiguration
+		expectedError bool
 	}{
 		{
 			name: "default config is set correctly",
@@ -94,6 +95,16 @@ func TestDocMapToUpgradeConfiguration(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "no UpgradeConfiguration found",
+			cfg: kubeadmapiv1.InitConfiguration{
+				TypeMeta: metav1.TypeMeta{
+					APIVersion: kubeadmapiv1.SchemeGroupVersion.String(),
+					Kind:       constants.InitConfigurationKind,
+				},
+			},
+			expectedError: true,
+		},
 	}
 
 	for _, tc := range tests {
@@ -107,11 +118,13 @@ func TestDocMapToUpgradeConfiguration(t *testing.T) {
 				t.Fatalf("Unexpect error of SplitYAMLDocuments: %v", err)
 			}
 			cfg, err := DocMapToUpgradeConfiguration(docmap)
-			if err != nil {
+			if (err != nil) != tc.expectedError {
-				t.Fatalf("unexpected error of DocMapToUpgradeConfiguration: %v\nconfig: %s", err, string(b))
+				t.Fatalf("failed DocMapToUpgradeConfiguration:\n\texpected error: %t\n\t  actual error: %v", tc.expectedError, err)
 			}
-			if diff := cmp.Diff(*cfg, tc.expectedCfg, cmpopts.IgnoreFields(kubeadmapi.UpgradeConfiguration{}, "Timeouts")); diff != "" {
+			if err == nil {
-				t.Fatalf("DocMapToUpgradeConfiguration returned unexpected diff (-want,+got):\n%s", diff)
+				if diff := cmp.Diff(*cfg, tc.expectedCfg, cmpopts.IgnoreFields(kubeadmapi.UpgradeConfiguration{}, "Timeouts")); diff != "" {
+					t.Fatalf("DocMapToUpgradeConfiguration returned unexpected diff (-want,+got):\n%s", diff)
+				}
 			}
 		})
 	}