Merge pull request #83661 from jfbai/fix-kubeadm-join

Add warning when --certificate-key is set and --control-plane is not.

cmd/kubeadm/app/cmd/join.go

@@ -342,6 +342,9 @@ func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Wri
 
 	// if not joining a control plane, unset the ControlPlane object
 	if !opt.controlPlane {
+		if opt.externalcfg.ControlPlane != nil {
+			klog.Warningf("[preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when %s flag is not set.", options.ControlPlane)
+		}
 		opt.externalcfg.ControlPlane = nil
 	}