How to Enable HTTP/2 in Apache

HTTP/2, often touted as the future of web protocols, brings a multitude of benefits, including multiplexing, server push, and header compression. These advancements not only enhance the speed of web page loading but also improve overall server performance, making HTTP/2 a must-have for any competitive website.

However, running HTTP/2 on Apache, especially on an Ubuntu server, involves more than just a simple switch. It requires an environment that supports this protocol. Notably, HTTP/2 operates exclusively over TLS (HTTPS), making it mandatory to have an SSL/TLS certificate. Additionally, Apache’s default Multi-Processing Module (MPM), mpm_prefork, is not compatible with HTTP/2. This necessitates a switch to a more suitable MPM like mpm_event, which is designed for high-performance, scalable network applications.

This article provides a comprehensive guide on how to enable HTTP/2 on Apache in Ubuntu, focusing on key steps like updating your server, verifying Apache versions, switching from mpm_prefork to mpm_event, enabling necessary modules, and configuring your server to fully leverage the benefits of HTTP/2. Whether you’re managing a small blog or a large e-commerce site, these insights will help you boost your site’s performance and user experience, keeping you at the forefront of web technology advancements.

Prerequisites

• Ubuntu server (18.04 or newer)
• Apache 2.4.17 or later
• Root or sudo privileges
• A valid SSL certificate (as HTTP/2 requires HTTPS)

Step by Step Guide

1. Update Your System
   Before proceeding, ensure your Ubuntu server is up-to-date. Run the following commands:

   sudo apt update && sudo apt upgrade  
   

2. Verify Apache Version
   HTTP/2 support is available in Apache 2.4.17 and later. Verify your Apache version with:

   apache2 -v 
   

   If your version is older, update Apache:

   sudo apt install apache2 
   

3. Disable mpm_prefork Module
   The mpm_prefork module is not compatible with HTTP/2. Disable it:

   sudo a2dismod mpm_prefork 
   

4. Enable mpm_event Module
   The mpm_event module is more efficient and compatible with HTTP/2. Enable it:

   sudo a2enmod mpm_event 
   

5. Enable Apache HTTP/2 Module
   Apache comes with an HTTP/2 module (mod_http2) that needs to be enabled. Execute:

   sudo a2enmod http2 
   

6. Configure Apache to Use HTTP/2
   Edit the Apache configuration file to enable HTTP/2. For each virtual host that should use HTTP/2, add Protocols h2 http/1.1 to the configuration. An example for default SSL configuration:

   sudo nano /etc/apache2/sites-available/000-default-le-ssl.conf 
   

   Add Protocols h2 http/1.1 under the <VirtualHost *:443> section.

   
   <VirtualHost *:443>
       ...
       Protocols h2 http/1.1
       ...
   </VirtualHost>
   
   

7. Test Configuration
   After editing the configuration file, check for syntax errors with:

   sudo apache2ctl configtest 
   

   If the output is Syntax OK, restart Apache to apply changes:

   sudo systemctl restart apache2 
   

8. Verify HTTP/2 and mpm_event Activation
   Ensure HTTP/2 is active using browser tools or online services. Confirm mpm_event is running with:

   apachectl -M | grep mpm 
   

   To confirm that HTTP/2 is enabled, you can use browser developer tools or online tools like HTTP/2 Test.

   

Conclusion

Enabling HTTP/2 in Apache on Ubuntu can greatly improve the loading times and efficiency of your website. By following these steps, you can leverage the benefits of the latest web protocol standards.