How to enable or disable Apache modules

Apache is a modular system in a sense that its functionality could be extended by using modules. A module could be installed into the system and Apache would then be configured to load the module during its startup.

Some of the mostly used modules are PHP and SSL which is to enable support for hosting PHP applications and provide encrypted web traffic respectively.

Apache modules could be enabled and disabled where and when required.

Steps to enable or disable Apache modules:

1. Install required Apache module if not not already installed.

   How to install Apache modules

2. Check if desired module is already loaded or enabled (optional).

   $ apachectl -t -D DUMP_MODULES
   Loaded Modules:
    core_module (static)
    so_module (static)
    watchdog_module (static)
    http_module (static)
    log_config_module (static)
    logio_module (static)
    version_module (static)
    unixd_module (static)
    access_compat_module (shared)
    alias_module (shared)
    auth_basic_module (shared)
    authn_core_module (shared)
    authn_file_module (shared)
    authz_core_module (shared)
    authz_host_module (shared)
    authz_user_module (shared)
    autoindex_module (shared)
    deflate_module (shared)
    dir_module (shared)
    env_module (shared)
    filter_module (shared)
    mime_module (shared)
    mpm_event_module (shared)
    negotiation_module (shared)
    reqtimeout_module (shared)
    setenvif_module (shared)
    socache_shmcb_module (shared)
    status_module (shared)

   Apache binary name for different distribution

   You can also use the -M option instead which is just a shortcut to the above command.

   $ apachectl -M

3. Add desired modules into Apache configuration file using the LoadModule directive.

   LoadModule php7_module /usr/lib/apache2/modules/libphp7.3.so
   LoadModule ssl_module /usr/lib/apache2/modules/mod_ssl.so

   Apache configuration files

   Ubuntu and other Debian derivatives has a2enmod utility installed and could be used to easily load Apache modules.

   $ sudo a2enmod php7.3 ssl
   [sudo] password for user:
   Considering dependency mpm_prefork for php7.3:
   Considering conflict mpm_event for mpm_prefork:
   Considering conflict mpm_worker for mpm_prefork:
   Module mpm_prefork already enabled
   Considering conflict php5 for php7.3:
   Enabling module php7.3.
   Considering dependency setenvif for ssl:
   Module setenvif already enabled
   Considering dependency mime for ssl:
   Module mime already enabled
   Considering dependency socache_shmcb for ssl:
   Module socache_shmcb already enabled
   Enabling module ssl.
   See /usr/share/doc/apache2/README.Debian.gz on how to configure SSL and create self-signed certificates.
   To activate the new configuration, you need to run:
     systemctl restart apache2

4. Restart Apache service for the modules to be loaded.

   How to start, restart and stop Apache service

5. Check if module is now enabled.

   $ apachectl -M
   Loaded Modules:
    core_module (static)
    so_module (static)
    watchdog_module (static)
    http_module (static)
    log_config_module (static)
    logio_module (static)
    version_module (static)
    unixd_module (static)
    access_compat_module (shared)
    alias_module (shared)
    auth_basic_module (shared)
    authn_core_module (shared)
    authn_file_module (shared)
    authz_core_module (shared)
    authz_host_module (shared)
    authz_user_module (shared)
    autoindex_module (shared)
    deflate_module (shared)
    dir_module (shared)
    env_module (shared)
    filter_module (shared)
    mime_module (shared)
    mpm_prefork_module (shared)
    negotiation_module (shared)
    php7_module (shared)
    reqtimeout_module (shared)
    setenvif_module (shared)
    socache_shmcb_module (shared)
    ssl_module (shared)
    status_module (shared)

6. Remove the added LoadModule directive or comment out the line by adding # at the beginning to disable loading the module.

   #LoadModule php7_module /usr/lib/apache2/modules/libphp7.3.so
   #LoadModule ssl_module /usr/lib/apache2/modules/mod_ssl.so

   Users of Ubuntu and other Debian derivatives can use a2dismod utility to disable Apache modules.

   $ sudo a2dismod php7.3 ssl
   [sudo] password for user:
   Module php7.3 disabled.
   Module ssl disabled.
   To activate the new configuration, you need to run:
     systemctl restart apache2

7. Restart Apache service for the modules to be unloaded.