LFCS Certification System Service Management (systemd) 3

Question 1

Which command would you use to reload systemd's unit file configuration from disk without rebooting?

Accepted Answer

systemctl daemon-reload

Answer

`systemctl daemon-reload` re-reads all unit files and regenerates dependency trees; it must be run after any unit file modification.

Question 2

A timer unit `backup.timer` is set to activate `backup.service`. Where must the timer unit be enabled for it to fire at boot?

Accepted Answer

The timer unit itself must be enabled and started with systemctl enable --now backup.timer

Answer

Timer units must be enabled and started independently; enabling the associated service does not activate the timer.

Question 3

Which directive limits the amount of CPU time a systemd service can use, expressed as a percentage of one CPU core?

Accepted Answer

CPUQuota=

Answer

`CPUQuota=50%` restricts the service to using no more than 50% of a single CPU core via the cgroup CPU controller.

Question 4

You need to temporarily override a vendor unit file without modifying it directly. Which approach is recommended?

Accepted Answer

Create a drop-in file in /etc/systemd/system/<unit>.d/override.conf

Answer

Drop-in files in `/etc/systemd/system/<unit>.d/` are merged with the vendor unit file, letting you override specific directives without touching the original.

Question 5

What does `systemctl isolate rescue.target` do?

Accepted Answer

Immediately switches to rescue.target, stopping all units not required by it

Answer

`isolate` starts the specified target and stops all units not pulled in by that target, effectively switching runlevels immediately.

LFCS Certification Practice Test

LFCS Certification Practice Test

LFCS Certification System Service Management (systemd) 3