Graduate kubeadm alpha certs command

cmd/kubeadm/app/cmd/alpha/alpha.go

@@ -29,9 +29,24 @@ func NewCmdAlpha(in io.Reader, out io.Writer) *cobra.Command {
 		Short: "Kubeadm experimental sub-commands",
 	}
 
-	cmd.AddCommand(newCmdCertsUtility(out))
 	cmd.AddCommand(newCmdKubeConfigUtility(out))
 	cmd.AddCommand(NewCmdSelfhosting(in))
 
+	certsCommand := NewCmdCertsUtility(out)
+	deprecateCertsCommand(certsCommand)
+	cmd.AddCommand(certsCommand)
+
 	return cmd
 }
+
+func deprecateCertsCommand(cmds ...*cobra.Command) {
+	const deprecatedMessage = "please use the same command under \"kubeadm certs\""
+
+	for _, cmd := range cmds {
+		cmd.Deprecated = deprecatedMessage
+		childCmds := cmd.Commands()
+		if len(childCmds) > 0 {
+			deprecateCertsCommand(childCmds...)
+		}
+	}
+}

cmd/kubeadm/app/cmd/alpha/certs.go

@@ -90,8 +90,8 @@ var (
 `)
 )
 
-// newCmdCertsUtility returns main command for certs phase
-func newCmdCertsUtility(out io.Writer) *cobra.Command {
+// NewCmdCertsUtility returns main command for certs phase
+func NewCmdCertsUtility(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:     "certs",
 		Aliases: []string{"certificates"},

cmd/kubeadm/app/cmd/cmd.go

@@ -90,8 +90,11 @@ func NewKubeadmCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 	cmds.AddCommand(NewCmdToken(out, err))
 	cmds.AddCommand(upgrade.NewCmdUpgrade(out))
 	cmds.AddCommand(alpha.NewCmdAlpha(in, out))
-
 	options.AddKubeadmOtherFlags(cmds.PersistentFlags(), &rootfsPath)
 
+	// TODO: remove "certs" from "alpha"
+	// https://github.com/kubernetes/kubeadm/issues/2291
+	cmds.AddCommand(alpha.NewCmdCertsUtility(out))
+
 	return cmds
 }