kubeadm: move show-join-command as a separate phase

cmd/kubeadm/app/cmd/init.go

@@ -21,9 +21,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"text/template"
 
-	"github.com/lithammer/dedent"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	flag "github.com/spf13/pflag"
@@ -48,46 +46,6 @@ import (
 	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 )
 
-var (
-	initDoneTempl = template.Must(template.New("init").Parse(dedent.Dedent(`
-		Your Kubernetes control-plane has initialized successfully!
-
-		To start using your cluster, you need to run the following as a regular user:
-
-		  mkdir -p $HOME/.kube
-		  sudo cp -i {{.KubeConfigPath}} $HOME/.kube/config
-		  sudo chown $(id -u):$(id -g) $HOME/.kube/config
-
-		Alternatively, if you are the root user, you can run:
-
-		  export KUBECONFIG=/etc/kubernetes/admin.conf
-
-		You should now deploy a pod network to the cluster.
-		Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
-		  https://kubernetes.io/docs/concepts/cluster-administration/addons/
-
-		{{if .ControlPlaneEndpoint -}}
-		{{if .UploadCerts -}}
-		You can now join any number of the control-plane node running the following command on each as root:
-
-		  {{.joinControlPlaneCommand}}
-
-		Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
-		As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
-		"kubeadm init phase upload-certs --upload-certs" to reload certs afterward.
-
-		{{else -}}
-		You can now join any number of control-plane nodes by copying certificate authorities
-		and service account keys on each node and then running the following as root:
-
-		  {{.joinControlPlaneCommand}}
-
-		{{end}}{{end}}Then you can join any number of worker nodes by running the following on each as root:
-
-		{{.joinWorkerCommand}}
-		`)))
-)
-
 // initOptions defines all the init options exposed via flags by kubeadm init.
 // Please note that this structure includes the public kubeadm config API, but only a subset of the options
 // supported by this api will be exposed as a flag.
@@ -151,11 +109,7 @@ func newCmdInit(out io.Writer, initOptions *initOptions) *cobra.Command {
 			data := c.(*initData)
 			fmt.Printf("[init] Using Kubernetes version: %s\n", data.cfg.KubernetesVersion)
 
-			if err := initRunner.Run(args); err != nil {
+			return initRunner.Run(args)
-				return err
-			}
-
-			return showJoinCommand(data, out)
 		},
 		Args: cobra.NoArgs,
 	}
@@ -191,6 +145,7 @@ func newCmdInit(out io.Writer, initOptions *initOptions) *cobra.Command {
 	initRunner.AppendPhase(phases.NewBootstrapTokenPhase())
 	initRunner.AppendPhase(phases.NewKubeletFinalizePhase())
 	initRunner.AppendPhase(phases.NewAddonPhase())
+	initRunner.AppendPhase(phases.NewShowJoinCommandPhase())
 
 	// sets the data builder function, that will be used by the runner
 	// both when running the entire workflow or single phases
@@ -565,39 +520,3 @@ func (d *initData) PatchesDir() string {
 	}
 	return ""
 }
-
-func printJoinCommand(out io.Writer, adminKubeConfigPath, token string, i *initData) error {
-	joinControlPlaneCommand, err := cmdutil.GetJoinControlPlaneCommand(adminKubeConfigPath, token, i.CertificateKey(), i.skipTokenPrint, i.skipCertificateKeyPrint)
-	if err != nil {
-		return err
-	}
-
-	joinWorkerCommand, err := cmdutil.GetJoinWorkerCommand(adminKubeConfigPath, token, i.skipTokenPrint)
-	if err != nil {
-		return err
-	}
-
-	ctx := map[string]interface{}{
-		"KubeConfigPath":          adminKubeConfigPath,
-		"ControlPlaneEndpoint":    i.Cfg().ControlPlaneEndpoint,
-		"UploadCerts":             i.uploadCerts,
-		"joinControlPlaneCommand": joinControlPlaneCommand,
-		"joinWorkerCommand":       joinWorkerCommand,
-	}
-
-	return initDoneTempl.Execute(out, ctx)
-}
-
-// showJoinCommand prints the join command after all the phases in init have finished
-func showJoinCommand(i *initData, out io.Writer) error {
-	adminKubeConfigPath := i.KubeConfigPath()
-
-	// Prints the join command, multiple times in case the user has multiple tokens
-	for _, token := range i.Tokens() {
-		if err := printJoinCommand(out, adminKubeConfigPath, token, i); err != nil {
-			return errors.Wrap(err, "failed to print join command")
-		}
-	}
-
-	return nil
-}

cmd/kubeadm/app/cmd/phases/init/showjoincommand.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package phases
+
+import (
+	"io"
+	"text/template"
+
+	"github.com/lithammer/dedent"
+	"github.com/pkg/errors"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
+	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
+)
+
+var (
+	initDoneTempl = template.Must(template.New("init").Parse(dedent.Dedent(`
+		Your Kubernetes control-plane has initialized successfully!
+
+		To start using your cluster, you need to run the following as a regular user:
+
+		  mkdir -p $HOME/.kube
+		  sudo cp -i {{.KubeConfigPath}} $HOME/.kube/config
+		  sudo chown $(id -u):$(id -g) $HOME/.kube/config
+
+		Alternatively, if you are the root user, you can run:
+
+		  export KUBECONFIG=/etc/kubernetes/admin.conf
+
+		You should now deploy a pod network to the cluster.
+		Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
+		  https://kubernetes.io/docs/concepts/cluster-administration/addons/
+
+		{{if .ControlPlaneEndpoint -}}
+		{{if .UploadCerts -}}
+		You can now join any number of the control-plane node running the following command on each as root:
+
+		  {{.joinControlPlaneCommand}}
+
+		Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
+		As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
+		"kubeadm init phase upload-certs --upload-certs" to reload certs afterward.
+
+		{{else -}}
+		You can now join any number of control-plane nodes by copying certificate authorities
+		and service account keys on each node and then running the following as root:
+
+		  {{.joinControlPlaneCommand}}
+
+		{{end}}{{end}}Then you can join any number of worker nodes by running the following on each as root:
+
+		{{.joinWorkerCommand}}
+		`)))
+)
+
+// NewShowJoinCommandPhase creates a kubeadm workflow phase that implements showing the join command.
+func NewShowJoinCommandPhase() workflow.Phase {
+	return workflow.Phase{
+		Name:         "show-join-command",
+		Short:        "Show the join command for control-plane and worker node",
+		Run:          showJoinCommand,
+		Dependencies: []string{"bootstrap-token", "upload-certs"},
+	}
+}
+
+// showJoinCommand prints the join command after all the phases in init have finished
+func showJoinCommand(c workflow.RunData) error {
+	data, ok := c.(InitData)
+	if !ok {
+		return errors.New("show-join-command phase invoked with an invalid data struct")
+	}
+
+	adminKubeConfigPath := data.KubeConfigPath()
+
+	// Prints the join command, multiple times in case the user has multiple tokens
+	for _, token := range data.Tokens() {
+		if err := printJoinCommand(data.OutputWriter(), adminKubeConfigPath, token, data); err != nil {
+			return errors.Wrap(err, "failed to print join command")
+		}
+	}
+
+	return nil
+}
+
+func printJoinCommand(out io.Writer, adminKubeConfigPath, token string, i InitData) error {
+	joinControlPlaneCommand, err := cmdutil.GetJoinControlPlaneCommand(adminKubeConfigPath, token, i.CertificateKey(), i.SkipTokenPrint(), i.SkipCertificateKeyPrint())
+	if err != nil {
+		return err
+	}
+
+	joinWorkerCommand, err := cmdutil.GetJoinWorkerCommand(adminKubeConfigPath, token, i.SkipTokenPrint())
+	if err != nil {
+		return err
+	}
+
+	ctx := map[string]interface{}{
+		"KubeConfigPath":          adminKubeConfigPath,
+		"ControlPlaneEndpoint":    i.Cfg().ControlPlaneEndpoint,
+		"UploadCerts":             i.UploadCerts(),
+		"joinControlPlaneCommand": joinControlPlaneCommand,
+		"joinWorkerCommand":       joinWorkerCommand,
+	}
+
+	return initDoneTempl.Execute(out, ctx)
+}

cmd/kubeadm/app/cmd/phases/workflow/phase.go

@@ -78,6 +78,9 @@ type Phase struct {
 	// ArgsValidator defines the positional arg function to be used for validating args for this phase
 	// If not set a phase will adopt the args of the top level command.
 	ArgsValidator cobra.PositionalArgs
+
+	// Dependencies is a list of phases that the specific phase depends on.
+	Dependencies []string
 }
 
 // AppendPhase adds the given phase to the nested, ordered sequence of phases.

cmd/kubeadm/app/cmd/phases/workflow/runner.go

@@ -198,6 +198,29 @@ func (e *Runner) Run(args []string) error {
 		return err
 	}
 
+	// precheck phase dependencies before actual execution
+	missedDeps := make(map[string][]string)
+	visited := make(map[string]struct{})
+	for _, p := range e.phaseRunners {
+		if run, ok := phaseRunFlags[p.generatedName]; !run || !ok {
+			continue
+		}
+		for _, dep := range p.Phase.Dependencies {
+			if _, ok := visited[dep]; !ok {
+				missedDeps[p.Phase.Name] = append(missedDeps[p.Phase.Name], dep)
+			}
+		}
+		visited[p.Phase.Name] = struct{}{}
+	}
+	if len(missedDeps) > 0 {
+		var msg strings.Builder
+		msg.WriteString("unresolved dependencies:")
+		for phase, missedPhases := range missedDeps {
+			msg.WriteString(fmt.Sprintf("\n\tmissing %v phase(s) needed by %q phase", missedPhases, phase))
+		}
+		return errors.New(msg.String())
+	}
+
 	// builds the runner data
 	var data RunData
 	if data, err = e.InitData(args); err != nil {