systemd targets

systemd replaces traditional SysVinit runlevels with predefined groups of units called targets. Targets are usually defined according to the intended use of the system, and ensure that required dependencies for that use are met.

The system boots to the target described in /lib/systemd/system/default.target. This file is a symlink that can be changed when booting to a different target is desired.

Appending systemd.unit=custom.target to the kernel’s boot arguments will override the default target.