On 07/05/2014 06:21 PM, Tim wrote:
Allegedly, on or about 05 July 2014, Patrick O'Callaghan sent:
More to the point, to understand "target" I now have to understand "unit". According to systemd(1), under the heading "Concepts", we find that "systemd provides a dependency system between various entities called "units" of 12 different types". 12 different types! I'm getting a sinking feeling already ...
The old system was considered bad, because it had 6 run levels, of which a few of them were never used. Now we have 12?
Twelve different types of *units*, of which service and target are two. A target is like a runlevel (it groups units together), except that more than one can be active at a time. A target can be marked "AllowIsolate=yes", which means that it can be treated like a sysvinit runlevel (start everything listed in it and stop everything else).
Note also that backward-compatible symlinks are provided in /usr/lib/systemd/system for the targets that correspond to the "classical" sysvinit runlevels:
runlevel0.target -> poweroff.target runlevel1.target -> rescue.target runlevel2.target -> multi-user.target runlevel3.target -> multi-user.target runlevel4.target -> multi-user.target runlevel5.target -> graphical.target runlevel6.target -> reboot.target
https://fedoraproject.org/wiki/Systemd#How_do_I_change_the_target_.28runleve...
https://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet