How to Configure mod_wsgi with Apache on AlmaLinux

When it comes to hosting Python web applications, mod_wsgi is a popular Apache module that allows you to integrate Python applications seamlessly with the Apache web server. For developers and system administrators using AlmaLinux, a free and open-source RHEL-based distribution, configuring mod_wsgi is an essential step for deploying robust Python-based web solutions.

This guide provides a detailed, step-by-step process for configuring mod_wsgi with Apache on AlmaLinux. By the end of this tutorial, you will have a fully functioning Python web application hosted using mod_wsgi.

Prerequisites

Before diving into the configuration process, ensure the following prerequisites are met:

1. A Running AlmaLinux System: This guide assumes you have AlmaLinux 8 or later installed.
2. Apache Installed: The Apache web server should be installed and running.
3. Python Installed: Ensure Python 3.x is installed.
4. Root or Sudo Privileges: You’ll need administrative access to perform system modifications.

Step 1: Update Your AlmaLinux System

Keeping your system updated ensures you have the latest security patches and software versions. Open a terminal and run:

sudo dnf update -y

Once the update completes, restart the system if necessary:

sudo reboot

Step 2: Install Apache (if not already installed)

Apache is a core component of this setup. Install it using the dnf package manager:

sudo dnf install httpd -y

Enable and start the Apache service:

sudo systemctl enable httpd
sudo systemctl start httpd

Verify that Apache is running:

sudo systemctl status httpd

Open your browser and navigate to your server’s IP address to confirm Apache is serving the default web page.

Step 3: Install Python and Dependencies

AlmaLinux typically comes with Python pre-installed, but it’s important to verify the version. Run:

python3 --version

If Python is not installed, install it with:

sudo dnf install python3 python3-pip -y

You’ll also need the development tools and Apache HTTPD development libraries:

sudo dnf groupinstall "Development Tools" -y
sudo dnf install httpd-devel -y

Step 4: Install mod_wsgi

The mod_wsgi package allows Python web applications to interface with Apache. Install it using pip:

pip3 install mod_wsgi

Verify the installation by checking the mod_wsgi-express binary:

mod_wsgi-express --version

Step 5: Configure mod_wsgi with Apache

Generate mod_wsgi Module

Use mod_wsgi-express to generate a .so file for Apache:

mod_wsgi-express module-config

This command outputs configuration details similar to the following:

LoadModule wsgi_module "/usr/local/lib/python3.8/site-packages/mod_wsgi/server/mod_wsgi-py38.so"
WSGIPythonHome "/usr"

Copy this output and save it for the next step.

Add Configuration to Apache

Create a new configuration file for mod_wsgi in the Apache configuration directory. Typically, this is located at /etc/httpd/conf.d/.

sudo nano /etc/httpd/conf.d/mod_wsgi.conf

Paste the output from the mod_wsgi-express module-config command into this file. Save and close the file.

Step 6: Deploy a Python Application

Create a Sample Python Web Application

For demonstration purposes, create a simple Python WSGI application. Navigate to /var/www/ and create a directory for your app:

sudo mkdir /var/www/myapp
cd /var/www/myapp

Create a new file named app.wsgi:

sudo nano app.wsgi

Add the following code:

def application(environ, start_response):
    status = '200 OK'
    output = b'Hello, World! This is a Python application running with mod_wsgi.'

    response_headers = [('Content-Type', 'text/plain'), ('Content-Length', str(len(output)))]
    start_response(status, response_headers)

    return [output]

Save and close the file.

Set File Permissions

Ensure the Apache user (apache) can access the directory and files:

sudo chown -R apache:apache /var/www/myapp

Configure Apache to Serve the Application

Create a virtual host configuration file for the application:

sudo nano /etc/httpd/conf.d/myapp.conf

Add the following content:

<VirtualHost *:80>
    ServerName your-domain.com

    WSGIScriptAlias / /var/www/myapp/app.wsgi
    <Directory /var/www/myapp>
        Require all granted
    </Directory>

    ErrorLog /var/log/httpd/myapp_error.log
    CustomLog /var/log/httpd/myapp_access.log combined
</VirtualHost>

Replace your-domain.com with your domain name or server IP address. Save and close the file.

Restart Apache

Reload Apache to apply the changes:

sudo systemctl restart httpd

Step 7: Test Your Setup

Open your browser and navigate to your server’s domain or IP address. You should see the message:

Hello, World! This is a Python application running with mod_wsgi.

Step 8: Secure Your Server (Optional but Recommended)

Enable the Firewall

Allow HTTP and HTTPS traffic through the firewall:

sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload

Enable HTTPS with SSL/TLS

To secure your application, install an SSL certificate. You can use Let’s Encrypt for free SSL certificates. Install Certbot and enable HTTPS:

sudo dnf install certbot python3-certbot-apache -y
sudo certbot --apache

Follow the prompts to secure your site with HTTPS.

Conclusion

By following these steps, you’ve successfully configured mod_wsgi with Apache on AlmaLinux. This setup enables you to host Python web applications with ease and efficiency. While this guide focused on a simple WSGI application, the same principles apply to more complex frameworks like Django or Flask.

For production environments, always ensure your application and server are optimized and secure. Configuring proper logging, load balancing, and monitoring are key aspects of maintaining a reliable Python web application.

Feel free to explore the capabilities of mod_wsgi further and unlock the full potential of hosting Python web applications on AlmaLinux.