Introduces ExistingClusterKubeconfig option to unmanaged-cluster

cli/cmd/plugin/unmanaged-cluster/cmd/create.go

@@ -13,14 +13,15 @@ import (
 )
 
 type createUnmanagedOpts struct {
-	skipPreflightChecks    bool
-	clusterConfigFile      string
-	infrastructureProvider string
-	tkrLocation            string
-	cni                    string
-	podcidr                string
-	servicecidr            string
-	portMapping            []string
+	skipPreflightChecks       bool
+	clusterConfigFile         string
+	existingClusterKubeconfig string
+	infrastructureProvider    string
+	tkrLocation               string
+	cni                       string
+	podcidr                   string
+	servicecidr               string
+	portMapping               []string
 }
 
 const createDesc = `
@@ -52,6 +53,7 @@ var co = createUnmanagedOpts{}
 
 func init() {
 	CreateCmd.Flags().StringVarP(&co.clusterConfigFile, "config", "f", "", "A config file describing how to create the Tanzu environment")
+	CreateCmd.Flags().StringVarP(&co.existingClusterKubeconfig, "existing-cluster-kubeconfig", "e", "", "Use an existing kubeconfg to tanzu-ify a clsuter")
 	CreateCmd.Flags().StringVar(&co.infrastructureProvider, "provider", "", "The infrastructure provider for cluster creation; default is kind")
 	CreateCmd.Flags().StringVarP(&co.tkrLocation, "tkr", "t", "", "The URL to the image containing a Tanzu Kubernetes release")
 	CreateCmd.Flags().StringVarP(&co.cni, "cni", "c", "", "The CNI to deploy; default is antrea")
@@ -75,13 +77,14 @@ func create(cmd *cobra.Command, args []string) error {
 
 	// Determine our configuration to use
 	configArgs := map[string]string{
-		config.ClusterConfigFile: co.clusterConfigFile,
-		config.ClusterName:       clusterName,
-		config.Provider:          co.infrastructureProvider,
-		config.TKRLocation:       co.tkrLocation,
-		config.Cni:               co.cni,
-		config.PodCIDR:           co.podcidr,
-		config.ServiceCIDR:       co.servicecidr,
+		config.ClusterConfigFile:         co.clusterConfigFile,
+		config.ExistingClusterKubeconfig: co.existingClusterKubeconfig,
+		config.ClusterName:               clusterName,
+		config.Provider:                  co.infrastructureProvider,
+		config.TKRLocation:               co.tkrLocation,
+		config.Cni:                       co.cni,
+		config.PodCIDR:                   co.podcidr,
+		config.ServiceCIDR:               co.servicecidr,
 	}
 	clusterConfig, err := config.InitializeConfiguration(configArgs)
 	if err != nil {

cli/cmd/plugin/unmanaged-cluster/config/config.go

@@ -20,20 +20,21 @@ import (
 )
 
 const (
-	ClusterConfigFile = "ClusterConfigFile"
-	ClusterName       = "ClusterName"
-	Tty               = "Tty"
-	TKRLocation       = "TkrLocation"
-	Provider          = "Provider"
-	Cni               = "Cni"
-	PodCIDR           = "PodCidr"
-	ServiceCIDR       = "ServiceCidr"
-	configDir         = ".config"
-	tanzuConfigDir    = "tanzu"
-	yamlIndent        = 2
-	ProtocolTCP       = "tcp"
-	ProtocolUDP       = "udp"
-	ProtocolSCTP      = "sctp"
+	ClusterConfigFile         = "ClusterConfigFile"
+	ExistingClusterKubeconfig = "ExistingClusterKubeconfig"
+	ClusterName               = "ClusterName"
+	Tty                       = "Tty"
+	TKRLocation               = "TkrLocation"
+	Provider                  = "Provider"
+	Cni                       = "Cni"
+	PodCIDR                   = "PodCidr"
+	ServiceCIDR               = "ServiceCidr"
+	configDir                 = ".config"
+	tanzuConfigDir            = "tanzu"
+	yamlIndent                = 2
+	ProtocolTCP               = "tcp"
+	ProtocolUDP               = "udp"
+	ProtocolSCTP              = "sctp"
 )
 
 var defaultConfigValues = map[string]string{
@@ -60,8 +61,11 @@ type PortMap struct {
 type UnmanagedClusterConfig struct {
 	// ClusterName is the name of the cluster.
 	ClusterName string `yaml:"ClusterName"`
-	// KubeconfigPath is the serialized path to the kubeconfig to use.
+	// KubeconfigPath is the location where the Kubeconfig will be persisted
+	// after the cluster is created.
 	KubeconfigPath string `yaml:"KubeconfigPath"`
+	// ExistingClusterKubeconfig is the serialized path to the kubeconfig to use of an existing cluster.
+	ExistingClusterKubeconfig string `yaml:"ExistingClusterKubeconfig"`
 	// NodeImage is the host OS image to use for Kubernetes nodes.
 	// It is typically resolved, automatically, in the Taznu Kubernetes Release (TKR) BOM,
 	// but also can be overridden in configuration.
@@ -161,7 +165,7 @@ func InitializeConfiguration(commandArgs map[string]string) (*UnmanagedClusterCo
 	}
 
 	// Sanatize the filepath for the provided kubeconfig
-	config.KubeconfigPath = sanatizeKubeconfigPath(config.KubeconfigPath)
+	config.ExistingClusterKubeconfig = sanatizeKubeconfigPath(config.ExistingClusterKubeconfig)
 
 	return config, nil
 }

cli/cmd/plugin/unmanaged-cluster/tanzu/tanzu.go

@@ -173,13 +173,23 @@ func (t *UnmanagedCluster) Deploy(scConfig *config.UnmanagedClusterConfig) error
 	log.Style(outputIndent, color.Faint).Infof("%s\n", t.kappControllerBundle.GetRegistryURL())
 
 	// 4. Create the cluster
-	log.Eventf(logger.RocketEmoji, "Creating cluster %s\n", scConfig.ClusterName)
-	createdCluster, err := runClusterCreate(scConfig)
-	if err != nil {
-		return fmt.Errorf("failed to create cluster, Error: %s", err.Error())
+	var clusterToUse *cluster.KubernetesCluster
+
+	if scConfig.ExistingClusterKubeconfig != "" {
+		log.Eventf(logger.RocketEmoji, "Using existing cluster\n")
+		clusterToUse, err = useExistingCluster(scConfig)
+		if err != nil {
+			return fmt.Errorf("failed to use existing cluster, Error: %s", err.Error())
+		}
+	} else {
+		log.Eventf(logger.RocketEmoji, "Creating cluster %s\n", scConfig.ClusterName)
+		clusterToUse, err = runClusterCreate(scConfig)
+		if err != nil {
+			return fmt.Errorf("failed to create cluster, Error: %s", err.Error())
+		}
 	}
 
-	kcBytes := createdCluster.Kubeconfig
+	kcBytes := clusterToUse.Kubeconfig
 	log.Style(outputIndent, color.Faint).Info("To troubleshoot, use:\n")
 	log.Style(outputIndent, color.Faint).Infof("kubectl ${COMMAND} --kubeconfig %s\n", scConfig.KubeconfigPath)
 
@@ -568,13 +578,11 @@ func resolveKappBundle(t *UnmanagedCluster) error {
 }
 
 func runClusterCreate(scConfig *config.UnmanagedClusterConfig) (*cluster.KubernetesCluster, error) {
-	if scConfig.KubeconfigPath == "" {
-		clusterDir, err := resolveClusterDir(scConfig.ClusterName)
-		if err != nil {
-			return nil, err
-		}
-		scConfig.KubeconfigPath = filepath.Join(clusterDir, "kube.conf")
+	clusterDir, err := resolveClusterDir(scConfig.ClusterName)
+	if err != nil {
+		return nil, err
 	}
+	scConfig.KubeconfigPath = filepath.Join(clusterDir, "kube.conf")
 
 	clusterManager := cluster.NewClusterManager(scConfig)
 
@@ -584,7 +592,7 @@ func runClusterCreate(scConfig *config.UnmanagedClusterConfig) (*cluster.Kuberne
 		}
 	}
 
-	err := blockForPullingBaseImage(clusterManager, scConfig)
+	err = blockForPullingBaseImage(clusterManager, scConfig)
 	if err != nil {
 		return nil, err
 	}
@@ -597,6 +605,20 @@ func runClusterCreate(scConfig *config.UnmanagedClusterConfig) (*cluster.Kuberne
 	return kc, nil
 }
 
+func useExistingCluster(scConfig *config.UnmanagedClusterConfig) (*cluster.KubernetesCluster, error) {
+	scConfig.KubeconfigPath = scConfig.ExistingClusterKubeconfig
+	noopManager := cluster.NewNoopClusterManager()
+
+	kc, err := noopManager.Create(scConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	log.Style(outputIndent, color.FgYellow).Warn("Warning: Components installed using this method will need to be manually removed.\n")
+
+	return kc, nil
+}
+
 func blockForPullingBaseImage(cm cluster.Manager, scConfig *config.UnmanagedClusterConfig) error {
 	// start a go routine to animate the downloading logs while the docker exec gets the image
 	ctx, cancel := context.WithCancel(context.Background())