kubeadm: respect user specified image repository when using Kubernetes ci version

cmd/kubeadm/app/constants/constants.go

@@ -364,6 +364,9 @@ const (
 	// TODO: Find a better place for this constant
 	YAMLDocumentSeparator = "---\n"
 
+	// CIKubernetesVersionPrefix is the prefix for CI Kubernetes version
+	CIKubernetesVersionPrefix = "ci/"
+
 	// DefaultAPIServerBindAddress is the default bind address for the API Server
 	DefaultAPIServerBindAddress = "0.0.0.0"
 

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

@@ -94,7 +94,7 @@ func NormalizeKubernetesVersion(cfg *kubeadmapi.ClusterConfiguration) error {
 	isCIVersion := kubeadmutil.KubernetesIsCIVersion(cfg.KubernetesVersion)
 
 	// Requested version is automatic CI build, thus use KubernetesCI Image Repository for core images
-	if isCIVersion {
+	if isCIVersion && cfg.ImageRepository == kubeadmapiv1.DefaultImageRepository {
 		cfg.CIImageRepository = constants.DefaultCIImageRepository
 	}
 
@@ -106,7 +106,7 @@ func NormalizeKubernetesVersion(cfg *kubeadmapi.ClusterConfiguration) error {
 
 	// Requested version is automatic CI build, thus mark CIKubernetesVersion as `ci/<resolved-version>`
 	if isCIVersion {
-		cfg.CIKubernetesVersion = fmt.Sprintf("ci/%s", ver)
+		cfg.CIKubernetesVersion = fmt.Sprintf("%s%s", constants.CIKubernetesVersionPrefix, ver)
 	}
 
 	cfg.KubernetesVersion = ver

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

@@ -18,6 +18,7 @@ package config
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 
 	"github.com/lithammer/dedent"
@@ -26,6 +27,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/version"
 	apimachineryversion "k8s.io/apimachinery/pkg/version"
 
+	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmapiv1old "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta2"
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
@@ -452,3 +454,97 @@ func TestIsKubeadmPrereleaseVersion(t *testing.T) {
 		})
 	}
 }
+
+func TestNormalizeKubernetesVersion(t *testing.T) {
+	validVersion := fmt.Sprintf("v%v", constants.MinimumControlPlaneVersion)
+	validCIVersion := fmt.Sprintf("%s%s", constants.CIKubernetesVersionPrefix, validVersion)
+	tests := []struct {
+		name        string
+		cfg         *kubeadmapi.ClusterConfiguration
+		expectedCfg *kubeadmapi.ClusterConfiguration
+		expectErr   bool
+	}{
+		{
+			name: "normal version, default image repository",
+			cfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion: validVersion,
+				ImageRepository:   kubeadmapiv1.DefaultImageRepository,
+			},
+			expectedCfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion:   validVersion,
+				CIKubernetesVersion: "",
+				ImageRepository:     kubeadmapiv1.DefaultImageRepository,
+				CIImageRepository:   "",
+			},
+			expectErr: false,
+		},
+		{
+			name: "normal version, custom image repository",
+			cfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion: validVersion,
+				ImageRepository:   "custom.repository",
+			},
+			expectedCfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion:   validVersion,
+				CIKubernetesVersion: "",
+				ImageRepository:     "custom.repository",
+				CIImageRepository:   "",
+			},
+			expectErr: false,
+		},
+		{
+			name: "ci version, default image repository",
+			cfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion: validCIVersion,
+				ImageRepository:   kubeadmapiv1.DefaultImageRepository,
+			},
+			expectedCfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion:   validVersion,
+				CIKubernetesVersion: validCIVersion,
+				ImageRepository:     kubeadmapiv1.DefaultImageRepository,
+				CIImageRepository:   constants.DefaultCIImageRepository,
+			},
+			expectErr: false,
+		},
+		{
+			name: "ci version, custom image repository",
+			cfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion: validCIVersion,
+				ImageRepository:   "custom.repository",
+			},
+			expectedCfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion:   validVersion,
+				CIKubernetesVersion: validCIVersion,
+				ImageRepository:     "custom.repository",
+				CIImageRepository:   "",
+			},
+			expectErr: false,
+		},
+		{
+			name: "unsupported old version",
+			cfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion: "v0.0.0",
+				ImageRepository:   kubeadmapiv1.DefaultImageRepository,
+			},
+			expectedCfg: &kubeadmapi.ClusterConfiguration{
+				KubernetesVersion:   "v0.0.0",
+				CIKubernetesVersion: "",
+				ImageRepository:     kubeadmapiv1.DefaultImageRepository,
+				CIImageRepository:   "",
+			},
+			expectErr: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := NormalizeKubernetesVersion(tc.cfg)
+			if !reflect.DeepEqual(tc.cfg, tc.expectedCfg) {
+				t.Errorf("expected ClusterConfiguration: %#v, got %#v", tc.expectedCfg, tc.cfg)
+			}
+			if !tc.expectErr && err != nil {
+				t.Errorf("unexpected failure: %v", err)
+			}
+		})
+	}
+}