Lab 17.1: Work with targets

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Doel

Find out what the system boots into, change it, switch targets without a reboot, and see how enable works.

Voordat je begint

Work on the console of server1 (not over SSH) as root.

Taken

Show the default target and all active targets.
Make the system boot into text mode (no desktop) by default.
Switch to text mode now, without a reboot. Then go back.
Enable httpd and show the link that systemd created. Which target pulls it in?
Reboot and check the default target and that httpd runs.

Controleer je werk

#systemctl get-default
#ls -l /etc/systemd/system/default.target
#ls /etc/systemd/system/multi-user.target.wants/ | grep httpd
#systemctl is-active httpd

get-default = multi-user.target.
default.target is a link to multi-user.target.
httpd.service is in multi-user.target.wants.

Hints

Toon de hints

systemctl set-default, systemctl isolate.
WantedBy= in the [Install] section of the unit.

Oplossing

Toon de oplossing

Default and active targets.

#systemctl get-default
#systemctl list-units -t target

Text mode by default.

#systemctl set-default multi-user.target

Switch now and back (on a system with a desktop).

#systemctl isolate multi-user.target
#systemctl isolate graphical.target

Enable and look at the link.

#systemctl enable --now httpd
#ls -l /etc/systemd/system/multi-user.target.wants/httpd.service
#grep WantedBy /usr/lib/systemd/system/httpd.service

Reboot and check.

#systemctl reboot
#systemctl get-default; systemctl is-active httpd

Work with targets

Doel

Voordat je begint

Taken

Controleer je werk

Hints

Oplossing

Mijn notities

Lessen voor dit lab

Commando's in dit lab