code: func (n *NsenterMounter) Unmount(target string) error {
  	args := []string{
  		"--mount=/rootfs/proc/1/ns/mnt",
  		"--",
  		n.absHostPath("umount"),
  		target,
  	}
  
  	glog.V(5).Infof("Unmount command: %v %v", nsenterPath, args)
  	exec := exec.New()
  	outputBytes, err := exec.Command(nsenterPath, args...).CombinedOutput()
  	if len(outputBytes) != 0 {
  		glog.V(5).Infof("Output from mount command: %v", string(outputBytes))
  	}
  
  	return err
  }
docs: // Unmount runs umount(8) in the host's mount namespace.