linuxexpert-practice-labs/labs/lpic-1/101-2-boot-the-system/README.md

LPIC-1 101.2: Booting the system

Booting into a different target from the GRUB menu, keeping the journal across reboots, and finding out which init the system runs.

Before you start

The lab makes the journal volatile: if /var/log/journal exists, it moves it aside (reset puts it back), so the journal is kept only in memory under /run/log/journal and is lost at every reboot. It also notes the current boot. Write answers to the files in /root/lab-answers/.

Tasks

1. Boot once with systemd.unit=rescue.target added at the GRUB menu, log in, and check /proc/cmdline. Check it yourself: /proc/cmdline showed the option during that boot, and the next normal boot didn't have it.
2. Make the journal persistent by creating /var/log/journal, reboot twice, then list the boots with journalctl --list-boots and read the previous one with journalctl -b -1.
3. Find out which init the VM runs with ps -p 1 -o comm=, then look at ls -l /sbin/init. Write the name of PID 1 on line 1 of /root/lab-answers/3, and the file /sbin/init points to on line 2.

Hints

• At the GRUB menu, e edits the entry for one boot; add the option to the end of the linux line and press Ctrl+X. If the menu doesn't show, hold Shift or press Esc while the VM starts.
• mkdir /var/log/journal, then systemd-tmpfiles --create --prefix /var/log/journal and journalctl --flush (or restart systemd-journald) to start using it without a reboot.
• journalctl --list-boots, journalctl -b -1 -n 20.
• ps -p 1 -o comm=, ls -l /sbin/init, readlink -f /sbin/init.