code: func (ds *dockerService) GenerateExpectedCgroupParent(cgroupParent string) (string, error) {
  	if cgroupParent != "" {
  		// if docker uses the systemd cgroup driver, it expects *.slice style names for cgroup parent.
  		// if we configured kubelet to use --cgroup-driver=cgroupfs, and docker is configured to use systemd driver
  		// docker will fail to launch the container because the name we provide will not be a valid slice.
  		// this is a very good thing.
  		if ds.cgroupDriver == "systemd" {
  			// Pass only the last component of the cgroup path to systemd.
  			cgroupParent = path.Base(cgroupParent)
  		}
  	}
  	klog.V(3).Infof("Setting cgroup parent to: %q", cgroupParent)
  	return cgroupParent, nil
  }
docs: // GenerateExpectedCgroupParent returns cgroup parent in syntax expected by cgroup driver