kubeadm: fix the bug that configurable KubernetesVersion not respected during kubeadm join

cmd/kubeadm/app/componentconfigs/kubelet.go

@@ -74,8 +74,11 @@ var kubeletHandler = handler{
 }
 
 func kubeletConfigFromCluster(h *handler, clientset clientset.Interface, clusterCfg *kubeadmapi.ClusterConfiguration) (kubeadmapi.ComponentConfig, error) {
+	// Resolve possible CI version labels
+	ver := strings.TrimPrefix(clusterCfg.KubernetesVersion, constants.CIKubernetesVersionPrefix)
+
 	// Read the ConfigMap from the cluster based on what version the kubelet is
-	k8sVersion, err := version.ParseGeneric(clusterCfg.KubernetesVersion)
+	k8sVersion, err := version.ParseGeneric(ver)
 	if err != nil {
 		return nil, err
 	}

cmd/kubeadm/app/constants/constants.go

@@ -355,6 +355,9 @@ 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

@@ -104,7 +104,7 @@ 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