因为供应商提供的编译环境是 ubuntu 14.04lts，比较老旧了，直接安装 openssh-server 安装不了，提示没有这个包，然后再网上找到相应的解决办法。

1. backup

   sudo cp -i /etc/apt/sources.list /etc/apt/sources.list.backup

2. add

   deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse 
   deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse 
   deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse 
   deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse 
   deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse 

3. update

   sudo apt-get update

4. install

   sudo apt-get install openssh-server

reference

https://www.shangmayuan.com/a/7ee036528f064f86b65dff3e.html