11.9 Summary

A newly installed Ubuntu system includes a base set of systemd units many of which run in the background to provide much of the functionality of the system. These units are categorized by type, the most common of which being targets and services. A target unit is simply a group of other units that are to be started collectively. The system has a default target unit which defines the other units which are to be started up each time the system boots. The most common targets are those which boot the system to either multi-user or graphical mode. The systemctl command-line tool provides a range of options for performing systemd unit configuration tasks, many of which are also available through the Cockpit web-based interface.