kubeadm: simply struct of joinOptions by removing joinControlPlane

Signed-off-by: Dave Chen <dave.chen@arm.com>

cmd/kubeadm/app/cmd/join.go

@@ -133,7 +133,6 @@ type joinOptions struct {
 	controlPlane          bool
 	ignorePreflightErrors []string
 	externalcfg           *kubeadmapiv1.JoinConfiguration
-	joinControlPlane      *kubeadmapiv1.JoinControlPlane
 	patchesDir            string
 	dryRun                bool
 }
@@ -210,7 +209,7 @@ func newCmdJoin(out io.Writer, joinOptions *joinOptions) *cobra.Command {
 		Args: cobra.MaximumNArgs(1),
 	}
 
-	addJoinConfigFlags(cmd.Flags(), joinOptions.externalcfg, joinOptions.joinControlPlane)
+	addJoinConfigFlags(cmd.Flags(), joinOptions.externalcfg)
 	addJoinOtherFlags(cmd.Flags(), joinOptions)
 
 	joinRunner.AppendPhase(phases.NewPreflightPhase())
@@ -241,22 +240,22 @@ func newCmdJoin(out io.Writer, joinOptions *joinOptions) *cobra.Command {
 }
 
 // addJoinConfigFlags adds join flags bound to the config to the specified flagset
-func addJoinConfigFlags(flagSet *flag.FlagSet, cfg *kubeadmapiv1.JoinConfiguration, jcp *kubeadmapiv1.JoinControlPlane) {
+func addJoinConfigFlags(flagSet *flag.FlagSet, cfg *kubeadmapiv1.JoinConfiguration) {
 	flagSet.StringVar(
 		&cfg.NodeRegistration.Name, options.NodeName, cfg.NodeRegistration.Name,
 		`Specify the node name.`,
 	)
 	flagSet.StringVar(
-		&jcp.CertificateKey, options.CertificateKey, jcp.CertificateKey,
+		&cfg.ControlPlane.CertificateKey, options.CertificateKey, cfg.ControlPlane.CertificateKey,
 		"Use this key to decrypt the certificate secrets uploaded by init.",
 	)
 	// add control plane endpoint flags to the specified flagset
 	flagSet.StringVar(
-		&jcp.LocalAPIEndpoint.AdvertiseAddress, options.APIServerAdvertiseAddress, jcp.LocalAPIEndpoint.AdvertiseAddress,
+		&cfg.ControlPlane.LocalAPIEndpoint.AdvertiseAddress, options.APIServerAdvertiseAddress, cfg.ControlPlane.LocalAPIEndpoint.AdvertiseAddress,
 		"If the node should host a new control plane instance, the IP address the API Server will advertise it's listening on. If not set the default network interface will be used.",
 	)
 	flagSet.Int32Var(
-		&jcp.LocalAPIEndpoint.BindPort, options.APIServerBindPort, jcp.LocalAPIEndpoint.BindPort,
+		&cfg.ControlPlane.LocalAPIEndpoint.BindPort, options.APIServerBindPort, cfg.ControlPlane.LocalAPIEndpoint.BindPort,
 		"If the node should host a new control plane instance, the port for the API Server to bind to.",
 	)
 	// adds bootstrap token specific discovery flags to the specified flagset
@@ -326,7 +325,6 @@ func newJoinOptions() *joinOptions {
 
 	return &joinOptions{
 		externalcfg: externalcfg,
-		joinControlPlane: joinControlPlane,
 	}
 }
 
@@ -371,9 +369,6 @@ func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Wri
 		opt.externalcfg.Discovery.BootstrapToken.APIServerEndpoint = args[0]
 	}
 
-	// Include the JoinControlPlane with user flags
-	opt.externalcfg.ControlPlane = opt.joinControlPlane
-
 	// If not passing --control-plane, unset the ControlPlane object
 	if !opt.controlPlane {
 		// Use a defaulted JoinControlPlane object to detect if the user has passed
@@ -388,7 +383,7 @@ func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Wri
 			options.APIServerBindPort,
 		}
 
-		if *opt.joinControlPlane != *defaultJCP {
+		if *opt.externalcfg.ControlPlane != *defaultJCP {
 			klog.Warningf("[preflight] WARNING: --%s is also required when passing control-plane "+
 				"related flags such as [%s]", options.ControlPlane, strings.Join(joinControlPlaneFlags, ", "))
 		}

cmd/kubeadm/app/cmd/join_test.go

@@ -17,12 +17,15 @@ limitations under the License.
 package cmd
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/klog/v2"
 
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
@@ -36,6 +39,8 @@ discovery:
     token: abcdef.0123456789abcdef
     apiServerEndpoint: 1.2.3.4:6443
     unsafeSkipCAVerification: true
+controlPlane:
+  certificateKey: c39a18bae4a72e71b178661f437363da218a3efb83ddb03f1cd91d9ae1da41bd
 nodeRegistration:
   criSocket: /run/containerd/containerd.sock
   name: someName
@@ -74,6 +79,7 @@ func TestNewJoinData(t *testing.T) {
 		flags       map[string]string
 		validate    func(*testing.T, *joinData)
 		expectError bool
+		expectWarn  bool
 	}{
 		// Join data passed using flags
 		{
@@ -184,6 +190,7 @@ func TestNewJoinData(t *testing.T) {
 					t.Errorf("Invalid ControlPlane")
 				}
 			},
+			expectWarn: true,
 		},
 		{
 			name: "fails if invalid preflight checks are provided",
@@ -246,6 +253,22 @@ func TestNewJoinData(t *testing.T) {
 			},
 			validate: expectedJoinIgnorePreflightErrors(sets.NewString("a", "b", "c", "d")),
 		},
+		{
+			name: "warn if --control-plane flag is not set",
+			flags: map[string]string{
+				options.APIServerBindPort: "8888",
+				options.FileDiscovery:     "https://foo", //required only to pass discovery validation
+			},
+			expectWarn: true,
+		},
+		{
+			name: "no warn if --control-plane flag is set",
+			flags: map[string]string{
+				options.APIServerBindPort: "8888",
+				options.FileDiscovery:     "https://bar", //required only to pass discovery validation
+				options.ControlPlane:      "true",
+			},
+		},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -253,6 +276,12 @@ func TestNewJoinData(t *testing.T) {
 			joinOptions := newJoinOptions()
 			cmd := newCmdJoin(nil, joinOptions)
 
+			// set klog output destination to bytes.Buffer so that log could be fetched and verified later.
+			var buffer bytes.Buffer
+			klog.SetOutput(&buffer)
+			klog.LogToStderr(false)
+			defer klog.LogToStderr(true)
+
 			// sets cmd flags (that will be reflected on the join options)
 			for f, v := range tc.flags {
 				cmd.Flags().Set(f, v)
@@ -260,6 +289,17 @@ func TestNewJoinData(t *testing.T) {
 
 			// test newJoinData method
 			data, err := newJoinData(cmd, tc.args, joinOptions, nil, kubeconfigFilePath)
+			klog.Flush()
+			msg := "WARNING: --control-plane is also required when passing control-plane"
+			if tc.expectWarn {
+				if !strings.Contains(buffer.String(), msg) {
+					t.Errorf("Haven't detected the warning message, expected: %v, actual: %v", msg, buffer.String())
+				}
+			} else {
+				if strings.Contains(buffer.String(), msg) {
+					t.Errorf("Expect no such warning message: %v, but got: %v", msg, buffer.String())
+				}
+			}
 			if err != nil && !tc.expectError {
 				t.Fatalf("newJoinData returned unexpected error: %v", err)
 			}