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Installing Certbot and renewing certificates

Introduction

Let’s Encrypt is a Certificate Authority (CA) that provides an easy way to obtain and install free TLS/SSL certificates, thereby enabling encrypted HTTPS on web servers. It simplifies the process by providing a software client, Certbot, that attempts to automate most (if not all) of the required steps. Currently, the entire process of obtaining and installing a certificate is fully automated on both Apache and Nginx.

In this tutorial, you will use Certbot to obtain a free SSL certificate for Apache on Ubuntu 18.04 and set up your certificate to renew automatically.

This tutorial will use a separate Apache virtual host file instead of the default configuration file. We recommend creating new Apache virtual host files for each domain because it helps to avoid common mistakes and maintains the default files as a fallback configuration.

Prerequisites

To follow this tutorial, you will need:

A fully registered domain name. This tutorial will use your_domain as an example throughout.

Both of the following DNS records set up for your server.

An A record with your_domain pointing to your server’s public IP address.

An A record with www.your_domain pointing to your server’s public IP address.

Apache installed. Be sure that you have a virtual host file for your domain. This tutorial will use /etc/apache2/sites-available/your_domain.conf as an example.

Step 1 — Installing Certbot

The first step to using Let’s Encrypt to obtain an SSL certificate is to install the Certbot software on your server.

Certbot is in very active development, so the Certbot packages provided by Ubuntu tend to be outdated. However, the Certbot developers maintain a Ubuntu software repository with up-to-date versions, so we’ll use that repository instead.

Install Certbot’s Apache package with apt:

sudo apt -y install certbot python3-certbot-apache

Certbot is now ready to use, but in order for it to configure SSL for Apache, we need to verify some of Apache’s configuration.

Step 2 — Set Up the SSL Certificate

Certbot needs to be able to find the correct virtual host in your Apache configuration for it to automatically configure SSL. Specifically, it does this by looking for a ServerName directive that matches the domain you request a certificate for.

You should have a VirtualHost block for your domain at /etc/apache2/sites-available/your_domain.com.conf with the ServerName directive already set appropriately.

To check, open the virtual host file for your domain using nano or your favorite text editor:

sudo nano /etc/apache2/sites-available/your_domain.conf

Find the existing ServerName line. It should look like this:

/etc/apache2/sites-available/your_domain.conf

...

ServerName your_domain;

...

If it does, exit your editor and move on to the next step.

If it doesn’t, update it to match. Then save the file, quit your editor, and verify the syntax of your configuration edits:

sudo apache2ctl configtest

If you get an error, reopen the virtual host file and check for any typos or missing characters. Once your configuration file’s syntax is correct, reload Apache to load the new configuration:

sudo systemctl reload apache2

Certbot can now find the correct VirtualHost block and update it.

Next, let’s update the firewall to allow HTTPS traffic.

Step 3 — Allowing HTTPS Through the Firewall

If you have the ufw firewall enabled, as recommended by the prerequisite guides, you’ll need to adjust the settings to allow for HTTPS traffic. Luckily, Apache registers a few profiles with ufw upon installation.

You can see the current setting by typing:

sudo ufw status

It will probably look like this, meaning that only HTTP traffic is allowed to the web server:

Output

Status: active

To Action From

-- ------ ----

OpenSSH ALLOW Anywhere

Apache ALLOW Anywhere

OpenSSH (v6) ALLOW Anywhere (v6)

Apache (v6) ALLOW Anywhere (v6)

To additionally let in HTTPS traffic, allow the Apache Full profile and delete the redundant Apache profile allowance:

sudo ufw allow 'Apache Full'

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