1.背景
服务器上安装了最新的Ubuntu Server 18.04，使用apt-get命令安装软件时，有时候速度比较慢，用国内的镜像源更换下apt-get的默认源。
2.实现
（1）编辑源文件，vim /etc/apt/sources.list ，将原源使用#注释掉。
（2）使用网易apt-get源，替换为如下（注意版本 不同，源不同，用不同的代码替换 ”bionic“）：
deb http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
（3）再执行apt-get update，apt-get upgrade，就配置好了。