Working with systemd Targets

The concept of runlevels in SysV has been reimagined and expressed as targets in `systemd`. Knowing how to manage, use, and manipulate targets will make your `systemd` management much easier. In this lab, we'll use the `runlevel` command that ships with `systemd` to determine system state, work with the default target, manipulate it, and then isolate to the new target. We'll also understand why some targets can be isolated and others can't, inspect the contents of targets to see what they can do, and finally get a better understanding of the relationship between the `poweroff`, `shutdown`, `halt`, and `reboot` commands and `systemctl`.