mrtg 錯誤：ERROR: Creating templock /usr/local/etc/mrtg/mrtg.cfg_l_5566: Permission denied at /usr/local/bin/mrtg line 1961.

因為都是用 mrtg 的權限跑 mrtg，結果有一天升級到 2.17.4_5,1 之後，就會出現這個錯誤訊息：

root@xxxx:~ # su -m mrtg -c '/usr/local/bin/mrtg /usr/local/etc/mrtg/mrtg.cfg'
2014-08-18 00:11:20: ERROR: Creating templock /usr/local/etc/mrtg/mrtg.cfg_l_5566: Permission denied at /usr/local/bin/mrtg line 1961.

解決方法很簡單，只要：

root@xxxx:~ # chown -R mrtg /usr/local/etc/mrtg/

就可以了。

怎麼那麼巧，就剛好出現 5566？