免费证书 https://letsencrypt.org/

https://certbot.eff.org/#ubuntuxenial-other

 

Install

On Ubuntu systems, the Certbot team maintains a PPA. Once you add it to your list of repositories all you'll need to do is apt-get the following packages.

$ sudo apt-get update
$ sudo apt-get install software-properties-common
$ sudo add-apt-repository ppa:certbot/certbot
$ sudo apt-get update
$ sudo apt-get install certbot 

Get Started

Certbot supports a number of different “plugins” that can be used to obtain and/or install certificates.

Since your server architecture doesn't yet support automatic installation you'll have to use the certonly command to obtain your certificate.

$ sudo certbot certonly