fsync config checkpoint files after writing

pkg/kubelet/kubeletconfig/util/files/files.go

@@ -83,6 +83,10 @@ func ReplaceFile(fs utilfs.Filesystem, path string, data []byte) error {
 	if _, err := tmpFile.Write(data); err != nil {
 		return err
 	}
+	// sync file, to ensure it's written in case a hard reset happens
+	if err := tmpFile.Sync(); err != nil {
+		return err
+	}
 	if err := tmpFile.Close(); err != nil {
 		return err
 	}

pkg/util/filesystem/defaultfs.go

@@ -101,6 +101,11 @@ func (file *defaultFile) Write(b []byte) (n int, err error) {
 	return file.file.Write(b)
 }
 
+// Sync via os.File.Sync
+func (file *defaultFile) Sync() error {
+	return file.file.Sync()
+}
+
 // Close via os.File.Close
 func (file *defaultFile) Close() error {
 	return file.file.Close()

pkg/util/filesystem/fakefs.go

@@ -107,6 +107,11 @@ func (file *fakeFile) Write(b []byte) (n int, err error) {
 	return file.file.Write(b)
 }
 
+// Sync via afero.File.Sync
+func (file *fakeFile) Sync() error {
+	return file.file.Sync()
+}
+
 // Close via afero.File.Close
 func (file *fakeFile) Close() error {
 	return file.file.Close()

pkg/util/filesystem/filesystem.go

@@ -45,5 +45,6 @@ type File interface {
 	// for now, the only os.File methods used are those below, add more as necessary
 	Name() string
 	Write(b []byte) (n int, err error)
+	Sync() error
 	Close() error
 }