code: func (s *Server) cleanupSandboxesOnShutdown(ctx context.Context) {
  	_, err := os.Stat(shutdownFile)
  	if err == nil || !os.IsNotExist(err) {
  		logrus.Debugf("shutting down all sandboxes, on shutdown")
  		s.stopAllPodSandboxes(ctx)
  		err = os.Remove(shutdownFile)
  		if err != nil {
  			logrus.Warnf("Failed to remove %q", shutdownFile)
  		}
  
  	}
  }
docs: // cleanupSandboxesOnShutdown Remove all running Sandboxes on system shutdown