From 6dbf154d438f919896917bd99e3b6b61510a5f2b Mon Sep 17 00:00:00 2001
From: Jianfei Bai <jfbai@hotmail.com>
Date: Sun, 13 Oct 2019 21:39:12 +0800
Subject: [PATCH] Add warning when --certificate-key is set and --control-plane
 is not.

---
 cmd/kubeadm/app/cmd/join.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cmd/kubeadm/app/cmd/join.go b/cmd/kubeadm/app/cmd/join.go
index 93bfb63c63c..87670da9e2e 100644
--- a/cmd/kubeadm/app/cmd/join.go
+++ b/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
 	}