1.13. Modifying existing unit files

Procedure

1. Depending on the extent of the required changes, pick one of the following approaches:

   • Create a directory for supplementary configuration files at /etc/systemd/system/<unit>.d/. This method is recommended for most use cases. You can extend the default configuration with additional functionality, while still referring to the original unit file. Changes to the default unit introduced with a package upgrade are therefore applied automatically. See Extending the default unit configuration for more information.
   • Create a copy of the original unit file from /usr/lib/systemd/system/`directory in the `/etc/systemd/system/ directory and make changes there. The copy overrides the original file, therefore changes introduced with the package update are not applied. This method is useful for making significant unit changes that should persist regardless of package updates. See Overriding the default unit configuration for details.
2. To return to the default configuration of the unit, delete custom-created configuration files in the /etc/systemd/system/ directory.

3. Apply changes to unit files without rebooting the system:

   # systemctl daemon-reload

   The daemon-reload option reloads all unit files and recreates the entire dependency tree, which is needed to immediately apply any change to a unit file. As an alternative, you can achieve the same result with the following command:

   # init q

4. If the modified unit file belongs to a running service, restart the service:

   # systemctl restart <name>.service