Certbot is meant to be run on the server where your website is hosted. If you don’t have administrative shell access to your webserver or you’re not familiar with command line server administration, you should check if your hosting provider has built-in Let’s Encrypt support by contacting them or checking this list of supporting providers.
Install
On Ubuntu systems, the Certbot team maintains a PPA. You can add it to your list of repositories and install Certbot by running the following commands.
$ sudo apt-get update
$ sudo apt-get install software-properties-common
$ sudo add-apt-repository universe
$ sudo add-apt-repository ppa:certbot/certbot
$ sudo apt-get update
$ sudo apt-get install certbot python-certbot-apache
Installing DNS plugins
Certbot’s DNS plugins are available for your system. These plugins can be used to automate obtaining a wildcard certificate from Let’s Encrypt’s ACMEv2 server. To use one of these plugins, you must have configured DNS for the domain you want to obtain a certificate for with a DNS provider that Certbot has a plugin for. A list of these plugins and more information about using them can be found here. To install one of these plugins, run the installation command above but replace certbot python-certbot-apache with python3-certbot-dns-PLUGIN, where PLUGIN is the name of the plugin you want to install. For instance, for the RFC2136 plugin this would be python3-certbot-dns-rfc2136.
Get Started
Certbot has an Apache plugin, which is supported on many platforms, and automates certificate installation.
$ sudo certbot --apache
Running this command will get a certificate for you and have Certbot edit your Apache configuration automatically to serve it. If you’re feeling more conservative and would like to make the changes to your Apache configuration by hand, you can use the certonlysubcommand:
$ sudo certbot --apache certonly
If you want to obtain a wildcard certificate using Let’s Encrypt’s new ACMEv2 server, you’ll also need to use one of Certbot’s DNS plugins. To do this, make sure the plugin for your DNS provider is installed using the instructions above and run a command like the following:
$ sudo certbot -a dns-plugin -i apache -d "*.example.com" -d example.com --server https://acme-v02.api.letsencrypt.org/directory
You’ll need to replace dns-plugin with the name of the DNS plugin you want to use. You may also need to provide additional flags such as the path to your API credentials as described in the documentation for the DNS plugin linked above. To learn more about how to use Certbot read this documentation.
Automating renewal
The Certbot packages on your system come with a cron job that will renew your certificates automatically before they expire. Since Let’s Encrypt certificates last for 90 days, it’s highly advisable to take advantage of this feature. You can test automatic renewal for your certificates by running this command:
$ sudo certbot renew --dry-run
More detailed information and options about renewal can be found in the full documentation.