Operate running systems

Question 1

You have forgotten the password for root. List the steps to reset root’s password

Answer 1

1. From boot loader menu, press e to edit grub
2. Move cursor to the end of the linux line and append rd.break
3. Ctrl + X to reboot
4. mount -o remount,rw /sysroot
5. chroot /sysroot
6. passwd root
7. touch /.autorelabel
8. Type exit twice

Question 2

How do you switch to a different target on a running system?

Answer 2

systemctl isolate multi-user.target

Question 3

Increase nice level on process 1234 to the highest priority

Answer 3

renice -n -19 1234

Question 4

Identify the currently active tuning profile the system is currently using

Answer 4

tuned-adm active

Question 5

List all available tuning profiles

Answer 5

tuned-adm list

Question 6

Switch the active tuning profile to the throughput-performance profile.

Answer 6

tuned-adm profile throughput-performance

tuned-adm active

Question 7

What command outputs the last 10 lines of the

system journal and continues to output new journal entries as they get written to the journal?

Answer 7

journalctl -f

Question 8

In addition to the visible content of the journal, there are fields attached to the log entries that
can only be seen when verbose output is turned on. What is this command?

Answer 8

journalctl -o verbose

Question 9

List journal entries at the err priority or higher.

Answer 9

journalctl -p err

Question 10

List all journal entries from today’s records.

Answer 10

journalctl –since today

Question 11

To store journals in /var/log/journal directory across reboots, what file would you set the Storage parameter to persistent?

Answer 11

vim /etc/systemd/journald.conf