a2ensite

Enable a virtual host

$ sudo a2ensite [virtual_host]

$ sudo a2ensite [[-q|--quiet]] [virtual_host]

a2ensite <site_name> [<site_name> ...]

<site_name>
    The name of the Apache virtual host configuration file (typically without the .conf extension) located in the /etc/apache2/sites-available/ directory. Multiple site names can be specified to enable several sites simultaneously.

a2ensite is a fundamental utility script prevalent on Debian-based Linux distributions, such as Ubuntu, designed to efficiently manage Apache HTTP Server virtual host configurations. Its primary function is to enable a specific virtual host. The command achieves this by creating a symbolic link from the configuration file located in the /etc/apache2/sites-available/ directory to the /etc/apache2/sites-enabled/ directory. This symlink instructs Apache to include the linked configuration when it processes its active sites.

While a2ensite successfully enables the site, it does not automatically trigger a reload or restart of the Apache service. Therefore, it is essential for administrators to manually reload or restart Apache (e.g., using sudo systemctl reload apache2 or sudo service apache2 reload) after running the command for the changes to take effect. This separation of tasks ensures that multiple configuration changes can be batched before a single service restart. The utility significantly streamlines the activation and deactivation process for various websites hosted on a single Apache instance, enhancing server management efficiency. It is typically part of the core apache2 package.

Root Privileges Required:
The command must be executed with root privileges (e.g., using sudo), as it modifies system directories and creates symbolic links in /etc/apache2/sites-enabled/.

Apache Reload/Restart:
After running a2ensite, Apache must be reloaded or restarted for the changes to take effect. The command itself does not perform this action.

Configuration Validity:
The target configuration file in /etc/apache2/sites-available/ must be a valid Apache virtual host configuration. a2ensite does not validate the syntax of the configuration file.

Complementary to a2dissite:
It is the counterpart to a2dissite, which disables a virtual host by removing the symbolic link.

Configuration files relevant to a2ensite are primarily stored in:
/etc/apache2/sites-available/ (where site configurations are placed and reside)
/etc/apache2/sites-enabled/ (where active site symlinks are created and managed by a2ensite)

a2ensite is a key component of the apache2-common or apache2 package, primarily developed for and used by Debian and Ubuntu Linux distributions. Its introduction aimed to simplify the management of Apache virtual hosts, offering a structured and user-friendly alternative to manually creating and removing symlinks. This utility has streamlined the process of activating and deactivating websites, significantly contributing to more efficient and less error-prone server administration within these environments.

a2dissite(8), a2enmod(8), a2dismod(8), systemctl(1), apache2ctl(8)