def umount(mountpoint, persist=False):
    """Unmount a filesystem"""
    cmd_args = ['umount', mountpoint]
    try:
        subprocess.check_output(cmd_args)
    except subprocess.CalledProcessError as e:
        log('Error unmounting {}\n{}'.format(mountpoint, e.output))
        return False

    if persist:
        return fstab_remove(mountpoint)
    return True
Unmount a filesystem