From 158cf5d61a0f49eb6e2910835965086acefb2c8b Mon Sep 17 00:00:00 2001
From: Ted Yu <yuzhihong@gmail.com>
Date: Mon, 19 Aug 2019 09:26:34 -0700
Subject: [PATCH] Check the error return from listener close

---
 cmd/kubeadm/app/preflight/checks.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/cmd/kubeadm/app/preflight/checks.go b/cmd/kubeadm/app/preflight/checks.go
index bff978ae922..adedc337b29 100644
--- a/cmd/kubeadm/app/preflight/checks.go
+++ b/cmd/kubeadm/app/preflight/checks.go
@@ -208,7 +208,10 @@ func (poc PortOpenCheck) Check() (warnings, errorList []error) {
 		errorList = []error{errors.Errorf("Port %d is in use", poc.port)}
 	}
 	if ln != nil {
-		ln.Close()
+		if err = ln.Close(); err != nil {
+			warnings = append(warnings,
+				errors.Errorf("when closing port %d, encountered %v", poc.port, err))
+		}
 	}
 
 	return nil, errorList