fix kubelet tls overwrite issue

cmd/kubelet/app/server.go

@@ -406,10 +406,12 @@ func InitializeTLS(s *options.KubeletServer) (*server.TLSOptions, error) {
 	if s.TLSCertFile == "" && s.TLSPrivateKeyFile == "" {
 		s.TLSCertFile = path.Join(s.CertDirectory, "kubelet.crt")
 		s.TLSPrivateKeyFile = path.Join(s.CertDirectory, "kubelet.key")
-		if err := crypto.GenerateSelfSignedCert(nodeutil.GetHostname(s.HostnameOverride), s.TLSCertFile, s.TLSPrivateKeyFile, nil, nil); err != nil {
-			return nil, fmt.Errorf("unable to generate self signed cert: %v", err)
+		if crypto.ShouldGenSelfSignedCerts(s.TLSCertFile, s.TLSPrivateKeyFile) {
+			if err := crypto.GenerateSelfSignedCert(nodeutil.GetHostname(s.HostnameOverride), s.TLSCertFile, s.TLSPrivateKeyFile, nil, nil); err != nil {
+				return nil, fmt.Errorf("unable to generate self signed cert: %v", err)
+			}
+			glog.V(4).Infof("Using self-signed cert (%s, %s)", s.TLSCertFile, s.TLSPrivateKeyFile)
 		}
-		glog.V(4).Infof("Using self-signed cert (%s, %s)", s.TLSCertFile, s.TLSPrivateKeyFile)
 	}
 	tlsOptions := &server.TLSOptions{
 		Config: &tls.Config{

pkg/genericapiserver/genericapiserver.go

@@ -692,7 +692,7 @@ func (s *GenericAPIServer) Run(options *options.ServerRunOptions) {
 			alternateDNS := []string{"kubernetes.default.svc", "kubernetes.default", "kubernetes"}
 			// It would be nice to set a fqdn subject alt name, but only the kubelets know, the apiserver is clueless
 			// alternateDNS = append(alternateDNS, "kubernetes.default.svc.CLUSTER.DNS.NAME")
-			if shouldGenSelfSignedCerts(options.TLSCertFile, options.TLSPrivateKeyFile) {
+			if crypto.ShouldGenSelfSignedCerts(options.TLSCertFile, options.TLSPrivateKeyFile) {
 				if err := crypto.GenerateSelfSignedCert(s.ClusterIP.String(), options.TLSCertFile, options.TLSPrivateKeyFile, alternateIPs, alternateDNS); err != nil {
 					glog.Errorf("Unable to generate self signed cert: %v", err)
 				} else {
@@ -731,28 +731,6 @@ func (s *GenericAPIServer) Run(options *options.ServerRunOptions) {
 	glog.Fatal(http.ListenAndServe())
 }
 
-// If the file represented by path exists and
-// readable, return true otherwise return false.
-func canReadFile(path string) bool {
-	f, err := os.Open(path)
-	if err != nil {
-		return false
-	}
-
-	defer f.Close()
-
-	return true
-}
-
-func shouldGenSelfSignedCerts(certPath, keyPath string) bool {
-	if canReadFile(certPath) || canReadFile(keyPath) {
-		glog.Infof("using existing apiserver.crt and apiserver.key files")
-		return false
-	}
-
-	return true
-}
-
 // Exposes the given group version in API.
 func (s *GenericAPIServer) InstallAPIGroup(apiGroupInfo *APIGroupInfo) error {
 	apiPrefix := s.APIGroupPrefix

pkg/util/crypto/crypto.go

@@ -33,6 +33,29 @@ import (
 	"time"
 )
 
+// ShouldGenSelfSignedCerts returns false if the certificate or key files already exists,
+// otherwise returns true.
+func ShouldGenSelfSignedCerts(certPath, keyPath string) bool {
+	if canReadFile(certPath) || canReadFile(keyPath) {
+		return false
+	}
+
+	return true
+}
+
+// If the file represented by path exists and
+// readable, returns true otherwise returns false.
+func canReadFile(path string) bool {
+	f, err := os.Open(path)
+	if err != nil {
+		return false
+	}
+
+	defer f.Close()
+
+	return true
+}
+
 // GenerateSelfSignedCert creates a self-signed certificate and key for the given host.
 // Host may be an IP or a DNS name
 // You may also specify additional subject alt names (either ip or dns names) for the certificate