code: func (idsc IsDockerSystemdCheck) Check() (warnings, errorList []error) {
  	warnings = []error{}
  	driver, err := util.GetCgroupDriverDocker(exec.New())
  	if err != nil {
  		errorList = append(errorList, err)
  		return nil, errorList
  	}
  	if driver != util.CgroupDriverSystemd {
  		err = errors.Errorf("detected %q as the Docker cgroup driver. "+
  			"The recommended driver is %q. "+
  			"Please follow the guide at https://kubernetes.io/docs/setup/cri/",
  			driver,
  			util.CgroupDriverSystemd)
  		warnings = append(warnings, err)
  	}
  	return warnings, nil
  }
docs: // Check validates if Docker is setup to use systemd as the cgroup driver.