LFCS Certification System Service Management (systemd) 4

Question 1

Which command shows the dependency tree for a given systemd unit?

Accepted Answer

systemctl list-dependencies graphical.target

Answer

`systemctl list-dependencies` displays a tree of all units required or wanted by the specified unit.

Question 2

A service needs to start only after the network is fully up with a routable address. Which directive and value should be used?

Accepted Answer

After=network-online.target

Answer

`After=network-online.target` ensures the service waits until at least one network interface has a routable address, unlike `network.target` which only means networking was initialized.

Question 3

What is the purpose of a systemd socket unit (.socket)?

Accepted Answer

It enables socket-based activation, starting the service only when a connection arrives

Answer

Socket activation means systemd listens on the socket and only launches the associated service when a client connects, enabling on-demand startup.

Question 4

Which `systemd-analyze` subcommand shows how long each unit took to start during the last boot?

Accepted Answer

systemd-analyze blame

Answer

`systemd-analyze blame` lists all units sorted by the time they took to initialize, helping identify boot slowdowns.

Question 5

You run `systemctl mask httpd`. What is the effect?

Accepted Answer

The unit is symlinked to /dev/null, preventing it from being started manually or automatically

Answer

Masking creates a symlink from the unit name to `/dev/null`, making it impossible to start by any means until explicitly unmasked.

LFCS Certification Practice Test

LFCS Certification Practice Test

LFCS Certification System Service Management (systemd) 4