Ubuntu 环境，当apache2重启提示：
* Starting web server apache2
apache2: Could not reliably determine the server's fully qualified domain name,
... waiting apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName
解决的问题是：
sudo vim /etc/apache2/sites-available/default
打开default文件后，在default文件顶端加入：
ServerName 127.0.0.1
重启apache2 就不会提示上述错误了。