Installing Drupal with Apache and Let’s Encrypt SSL on Debian 11 can seem like a daunting task, but with the right instructions and a little bit of patience, it can be done relatively easily. This article will provide a detailed, step-by-step guide on how to get everything set up and running smoothly.

First, let’s go over the prerequisites for this installation. You will need a server running Debian 11, access to the root user account, and a registered domain name. You will also need to have Apache, MySQL, and PHP installed on your server.

Once you have these prerequisites in place, you can begin the installation process.

• Log in to your server as the root user and update the package manager index:

apt update

• Install the Apache web server, PHP, and the necessary PHP extensions by running the following command:

apt install apache2 php php-mysql php-gd php-xml php-mbstring

• Enable the Apache mod_rewrite module, which is required for Drupal’s clean URLs feature:

a2enmod rewrite

• Restart the Apache web server to apply the changes:

systemctl restart apache2

• Next, we’ll need to create a MySQL database and user for Drupal. Log in to the MySQL shell as the root user:

mysql -u root -p

• Once you’re logged in, create a new database for Drupal:

CREATE DATABASE drupal;

• Then, create a new MySQL user and grant them access to the Drupal database:

CREATE USER 'drupaluser'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON drupal.* TO 'drupaluser'@'localhost';

• Finally, flush the MySQL privileges to apply the changes and exit the MySQL shell:

FLUSH PRIVILEGES;
EXIT;

• Now, we can download and install Drupal. First, download the latest stable version of Drupal using wget:

wget <https://www.drupal.org/download-latest/tar.gz>

• Extract the downloaded archive and move the resulting directory to the Apache web root directory:

tar xzf tar.gz
mv drupal-* /var/www/html/drupal

• Next, we need to set the correct permissions for the Drupal directory. Run the following commands to give the Apache user ownership of the Drupal directory and its contents:

cd /var/www/html/drupal
chown -R www-data:www-data .

• Now, we need to configure Apache to serve Drupal. Create a new Apache configuration file for Drupal by running the following command:

nano /etc/apache2/sites-available/drupal.conf

• Paste the following configuration into the file, replacing example.com with your registered domain name:

<VirtualHost *:80>
  ServerName example.com
  ServerAlias www.example.com
  DocumentRoot /var/www/html/drupal
   <Directory /var/www/html/drupal>
     Options -Indexes +
     Options -Indexes +FollowSymLinks
     AllowOverride All
     Require all granted
   </Directory>
 </VirtualHost>

• Save and close the file, then enable the new Apache configuration by running the following commands:

a2ensite drupal.conf
systemctl reload apache2

• Now, open a web browser and navigate to your domain name (e.g., http://example.com). You should see the Drupal installation page. Follow the on-screen instructions to complete the installation process.
• Once Drupal is installed, we can proceed to installing Let’s Encrypt SSL to secure our website. Install the Let’s Encrypt client certbot by running the following command:

apt install certbot

• To obtain a SSL certificate from Let’s Encrypt, run the following command, replacing example.com with your domain name:

certbot --apache -d example.com -d www.example.com

• This will automatically obtain a SSL certificate for your domain and configure Apache to use it. You should now be able to access your Drupal website over HTTPS.
• Finally, to ensure that your SSL certificate stays valid and is automatically renewed, you can set up a cron job to run the certbot renewal command periodically. Edit the crontab by running the following command:

crontab -e

• Add the following line to the end of the file, which will run the certbot renewal command every week:

0 0 * * 0 /usr/bin/certbot renew --quiet

And that’s it! Your Drupal website should now be up and running, securely served over HTTPS using Apache and Let’s Encrypt SSL on Debian 11.