code: func detectSystemd() bool {
  	if _, err := exec.LookPath("systemd-run"); err != nil {
  		klog.V(2).Infof("Detected OS without systemd")
  		return false
  	}
  	// Try to run systemd-run --scope /bin/true, that should be enough
  	// to make sure that systemd is really running and not just installed,
  	// which happens when running in a container with a systemd-based image
  	// but with different pid 1.
  	cmd := exec.Command("systemd-run", "--description=Kubernetes systemd probe", "--scope", "true")
  	output, err := cmd.CombinedOutput()
  	if err != nil {
  		klog.V(2).Infof("Cannot run systemd-run, assuming non-systemd OS")
  		klog.V(4).Infof("systemd-run failed with: %v", err)
  		klog.V(4).Infof("systemd-run output: %s", string(output))
  		return false
  	}
  	klog.V(2).Infof("Detected OS with systemd")
  	return true
  }
docs: // detectSystemd returns true if OS runs with systemd as init. When not sure
  // (permission errors, ...), it returns false.
  // There may be different ways how to detect systemd, this one makes sure that
  // systemd-runs (needed by Mount()) works.