Revised systemd target list

The following table replaces Figure 16-2 in Using and Administering Linux: Volume 1 – Zero to SysAdmin: Getting Started on Page 472. The original shows the SystemV runlevels in the leftmost column and is sorted in the historical SystemV sequence. In this replacement I have made the systemd targets the primary column and sorted them in a sequence that makes more sense for systemd. In general, targets with higher levels of functionality are at the top of the table and those with the least functionality are at the bottom.

systemd targetsSystemV runleveltarget aliasesDescription
default.target

This target is always aliased with a symbolic link to either multi-user.target or graphical.target. systemd always uses the default.target to start the system. The default.target should never be aliased to halt.target, poweroff.target, or reboot.target.
graphical.target5runlevel5.targetMulti-user.target with a GUI.

4runlevel4.targetUnused. Runlevel 4 was identical to runlevel 3 in the SystemV world. This target could be created and customized to start local services without changing the default multi-user.target.
multi-user.target3runlevel3.targetMultiuser with all services running but command line interface (CLI) only.

2runlevel2.targetMultiuser, without NFS but all other non-GUI services running.
rescue.target1runlevel1.targetA basic system including mounting the filesystems with only the most basic services running and a rescue shell on the main console.
emergency.targetS
No services are running; filesystems are not mounted. This is the most basic level of operation with only an emergency shell running on the main console for the user to interact with the system. Single user mode in SystemV.
halt.target

Halts the system without powering it down.
reboot.target6runlevel6.targetReboot
poweroff.target0runlevel0.targetHalts the system and turns the power off.