Do not close pod sync, use context cancel instead. (#402)

Closing the channel is racey and can lead to a panic on exit.
Instead rely on context cancellation to know if workers should exit.

vkubelet/vkubelet.go

@@ -104,11 +104,16 @@ func New(ctx context.Context, cfg Config) (s *Server, retErr error) {
 	tick := time.Tick(5 * time.Second)
 
 	go func() {
-		for range tick {
-			ctx, span := trace.StartSpan(ctx, "syncActualState")
-			s.updateNode(ctx)
-			s.updatePodStatuses(ctx)
-			span.End()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-tick:
+				ctx, span := trace.StartSpan(ctx, "syncActualState")
+				s.updateNode(ctx)
+				s.updatePodStatuses(ctx)
+				span.End()
+			}
 		}
 	}()
 
@@ -128,12 +133,6 @@ func (s *Server) Run(ctx context.Context) error {
 	return nil
 }
 
-// Stop shutsdown the server.
-// It does not shutdown pods assigned to the virtual node.
-func (s *Server) Stop() {
-	close(s.podCh)
-}
-
 // reconcile is the main reconciliation loop that compares differences between Kubernetes and
 // the active provider and reconciles the differences.
 func (s *Server) reconcile(ctx context.Context) {