// Start with the basics, verify that the cluster is healthy and get the configuration from the cluster (using the ConfigMap)
	klog.V(1).Infoln("[upgrade/apply] verifying health of cluster")
	klog.V(1).Infoln("[upgrade/apply] retrieving configuration from cluster")

			if len(args) > 0 {
				bto.TokenStr = args[0]
			}
			klog.V(1).Infoln("[token] validating mixed arguments")
			if err := validation.ValidateMixedArguments(tokenCmd.Flags()); err != nil {
				return err
			}

			if err := bto.ApplyTo(cfg); err != nil {
				return err
			}

			klog.V(1).Infoln("[token] getting Clientsets from kubeconfig file")

	klog.V(1).Infoln("[upgrade/plan] verifying health of cluster")
	klog.V(1).Infoln("[upgrade/plan] retrieving configuration from cluster")
	client, versionGetter, initCfg, upgradeCfg, err := enforceRequirements(flagSet, flags.applyPlanFlags, args, false, false, printer)
	if err != nil {
		return err
	}

	// Compute which upgrade possibilities there are

func (ContainerRuntimeCheck) Name() string {
	return "CRI"
}

// Check validates the container runtime
func (crc ContainerRuntimeCheck) Check() (warnings, errorList []error) {
	klog.V(1).Infoln("validating the container runtime")
	if err := crc.runtime.IsRunning(); err != nil {
		errorList = append(errorList, err)
	}
	return warnings, errorList
}

	// and validates JoinConfiguration
	if opt.externalcfg.NodeRegistration.Name == "" {
		klog.V(1).Infoln("[preflight] found NodeName empty; using OS hostname as NodeName")
	}

	if opt.externalcfg.ControlPlane != nil && opt.externalcfg.ControlPlane.LocalAPIEndpoint.AdvertiseAddress == "" {
		klog.V(1).Infoln("[preflight] found advertiseAddress empty; using default interface's IP address as advertiseAddress")
	}

	}

	// Configure the kubelet. In this short timeframe, kubeadm is trying to stop/restart the kubelet
	// Try to stop the kubelet service so no race conditions occur when configuring it
	if !data.DryRun() {
		klog.V(1).Infoln("[kubelet-start] Stopping the kubelet")
		kubeletphase.TryStopKubelet()
	} else {
		fmt.Println("[kubelet-start] Would stop the kubelet")
	}

func CreateInitStaticPodManifestFiles(manifestDir, patchesDir string, cfg *kubeadmapi.InitConfiguration, isDryRun bool) error {
	klog.V(1).Infoln("[control-plane] creating static Pod files")

	}
	// show the migration changes
	klog.V(2).Infof("the CoreDNS configuration has been migrated and applied: %v.", updatedCorefile)
	klog.V(2).Infoln("the old migration has been saved in the CoreDNS ConfigMap under the name [Corefile-backup]")
	klog.V(2).Infoln("The changes in the new CoreDNS Configuration are as follows:")
	for _, change := range changes {
		klog.V(2).Infof("%v", change.ToString())
	}
	return nil
}

// case the upstream upgrade fails, we delegate communication to the passed
// in "w" ResponseWriter.
func (h *TunnelingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	klog.V(4).Infoln("TunnelingHandler ServeHTTP")

	spdyProtocols := spdyProtocolsFromWebsocketProtocols(req)
	if len(spdyProtocols) == 0 {
		http.Error(w, "unable to upgrade: no tunneling spdy protocols provided", http.StatusBadRequest)

// If the PKI assets already exists in the target folder, they are used only if evaluated equal; otherwise an error is returned.
func CreatePKIAssets(cfg *kubeadmapi.InitConfiguration) error {
	klog.V(1).Infoln("creating PKI assets")

	// This structure cannot handle multilevel CA hierarchies.
	// This isn't a problem right now, but may become one in the future.

	var certList Certificates

	if cfg.Etcd.Local == nil {