deb http://mirrors.aliyun.com/ubuntu xenial main
deb http://mirrors.aliyun.com/ubuntu xenial universe
deb http://mirrors.aliyun.com/ubuntu xenial-security main
deb http://mirrors.aliyun.com/ubuntu xenial-security universe
deb http://mirrors.aliyun.com/ubuntu xenial-updates main
deb http://mirrors.aliyun.com/ubuntu xenial-updates universe