linuxexpert-practice-labs/labs/lfcs/1-2-processes-services/README.md

LFCS 1.2: Processes and services

Signals and nice values, running a service now and at boot, fixing a broken service, masking, and the default boot target.

Before you start

The lab creates user alice (password Lab-Pass-1), installs the cups print service and starts it, stops and disables any web server already installed, and sets the default boot target to graphical.target.

Tasks

1. As alice, start sleep 3000 in the background, find its PID without ps, give it nice value 15, then stop it with SIGTERM. Check it yourself: ps -o ni -p PID shows 15 before you stop it, and pgrep sleep prints nothing after.
2. Install nginx (or httpd), and make it run now and at every boot.
3. Put a typo in the web server's configuration and restart it. Find the exact error line in the logs and write it to /root/lab-answers/3. Then fix the typo, so the service is running again and curl -sI localhost returns a status line.
4. Make sure the cups service can't be started by anyone.
5. Make the system boot to a text login by default.

Hints

• pgrep -u, renice -n ... -p, kill.
• systemctl enable --now, systemctl is-active, systemctl is-enabled.
• systemctl status, journalctl -u ... -b, nginx -t or apachectl configtest.
• systemctl mask.
• systemctl get-default, systemctl set-default.