def activate_minion_cachedir(minion_id, base=None):
    '''
    Moves a minion from the requested/ cachedir into the active/ cachedir. This
    means that Salt Cloud has verified that a requested instance properly
    exists, and should be expected to exist from here on out.
    '''
    if base is None:
        base = __opts__['cachedir']

    fname = '{0}.p'.format(minion_id)
    src = os.path.join(base, 'requested', fname)
    dst = os.path.join(base, 'active')
    shutil.move(src, dst)