To begin, we will install certbot, a simple script that automatically renews our certificates and allows much easier creation of them. The command below is for Ubuntu distributions, but you can always check Certbot's official site for installation instructions. We have also included a command below to install certbot's Nginx/Apache plugin so you won't have to stop your webserver.

sudo apt install -y python3-certbot-nginx

Creating a Certificate

After installing certbot, we need to generate a certificate. There are a couple of ways to do that, but the easiest is to use the web server-specific certbot plugin you just installed.

Then, in the command below, you should replace example.com with the domain you would like to generate a certificate for. When you have multiple domains you would like certificates for, simply add more -d anotherdomain.com flags to the command. You can also look into generating a wildcard certificate but that is not covered in this tutorial.

When you are using certbot's Nginx/Apache plugin, you won't need to restart your webserver to have the certificate applied assuming that you've already configured the webservers to use SSL as instructed in the web server configuration step.

HTTP challenge

HTTP challenge requires you to expose port 80 for the challenge verification.

certbot certonly --nginx -d example.com

DNS challenge

DNS challenge requires you to create a new TXT DNS record to verify domain ownership, instead of having to expose port 80. The instructions are displayed when you run the certbot command below.

certbot -d example.com --manual --preferred-challenges dns certonly

Auto Renewal

You'll also probably want to configure the automatic renewal of certificates to prevent unexpected certificate expirations. You can open crontab with sudo crontab -e and add the line from below to the bottom of it for attempting renewal every day at 23 (11 PM).

Deploy hook would restart the Nginx service to apply a new certificate when it's renewed successfully. Change nginx in the restart command to suit your own needs, such as to apache or wings.

0 23 * * * certbot renew --quiet --deploy-hook "systemctl restart nginx"

Troubleshooting

If you get an Insecure Connection or SSL/TLS related error when trying to access your panel or wings, the certificate has likely expired. This can be easily fixed by renewing the SSL certificate, although using the command certbot renew might not do the job if port 80 is in use, as it'll return errors like: Error: Attempting to renew cert (domain) from /etc/letsencrypt/renew/domain.conf produced an unexpected error.

This will happen especially if you're running Nginx instead of Apache. The solution for this is to use Nginx or Apache plugins with --nginx and --apache. Alternatively, you can stop Nginx, then renew the certificate, finally restart Nginx. Replace nginx with your own web server or with wings should you be renewing the certificate for Wings.

Stop Nginx:

systemctl stop nginx

Renew the certificate:

certbot renew

Once the process has completed, you can restart Nginx:

systemctl start nginx

You may also need to restart Wings as not every service is able to automatically apply an updated certificate:

systemctl restart featherwings