How to validate your Apache configuration

Checking the Apache configuration is essential before restarting the service, especially after making changes to the config file. A failure to validate the configuration can lead to service disruption and affect the availability of hosted websites.

Apache offers a built-in feature to validate the configuration file, allowing you to identify and rectify any errors or warnings. By repeatedly checking the configuration files and resolving issues, you can ensure a smooth restart of the service.

Both apachectl and httpd tools are available to test the Apache configuration from the terminal, providing a convenient way to verify the syntax and overall validity of the configuration files.

1. Open your preferred terminal application.
2. Modify the Apache configuration file using your preferred text editor.

   $ sudo vi /etc/apache2/apache2.conf

   Related: Understanding Apache web server configuration files

3. Use apachectl or similar binaries to test the Apache configuration file syntax.

   $ sudo apachectl configtest
   AH00543: apache2: bad user name username
   Action 'configtest' failed.
   The Apache error log may have more information.

   Use -t option instead of configtest if you're using httpd or apache and not apachectl

   Related: Apache binary name for different distribution

4. Continue editing and testing the Apache configuration until the configtest option reports no errors.

   $ sudo apachectl configtest
   Syntax OK

5. Once the configuration is error-free, restart the Apache service to apply the changes.

   $ sudo systemctl restart apache2 # Ubuntu, Debian, openSUSE and SLES
   $ sudo systemctl restart httpd # CentOS and Red Hat

   Related: How to manage the Apache web server service