RHCSA Systemd and Service Management Questions and Answers

Question 1

A system administrator needs to troubleshoot a failing service named `httpd.service`.
Which of the following commands provides the most direct and comprehensive way to view all log entries for only that specific service since the system last booted?

Accepted Answer

journalctl -u httpd.service -b

Answer

systemctl status httpd.service

Answer

cat /var/log/messages | grep httpd

Answer

journalctl /usr/sbin/httpd

Question 2

What is the key difference between disabling a service with `systemctl disable` and masking a service with `systemctl mask`?

Accepted Answer

`disable` prevents the service from starting automatically at boot, but it can still be started manually or as a dependency. `mask` links the service to `/dev/null`, preventing it from being started under any circumstances.

Answer

`disable` stops the service immediately, whereas `mask` only prevents it from starting on the next boot.

Answer

`disable` is a temporary action that is reset on reboot, whereas `mask` is persistent.

Answer

`mask` removes the service's unit file from the system, while `disable` only removes the startup symlinks.

Question 3

After creating a new systemd unit file at `/etc/systemd/system/custom.service`, a system administrator tries to start it but receives an error that the unit is not found. Which command must be run first for systemd to recognize the new unit file?

Accepted Answer

systemctl daemon-reload

Answer

systemctl restart systemd

Answer

systemctl refresh-units

Answer

systemctl enable custom.service

Question 4

A server is currently running in the `graphical.target` (runlevel 5). An administrator needs to switch to `multi-user.target` (runlevel 3) immediately to perform maintenance, but wants the server to boot back into `graphical.target` on the next reboot. Which command will achieve this temporary change?

Accepted Answer

systemctl isolate multi-user.target

Answer

systemctl set-default multi-user.target

Answer

telinit 3

Answer

systemctl disable graphical.target

Question 5

After editing the main configuration file for a running web server, you need to apply the changes without dropping active user connections. Assuming the service unit supports this functionality, which command is the most appropriate?

Accepted Answer

systemctl reload httpd.service

Answer

systemctl restart httpd.service

Answer

systemctl kill -s SIGHUP httpd.service

Answer

systemctl daemon-reload

Question 6

Which of the following commands is used to change the default target the system will boot into, making the change persistent across reboots?

Accepted Answer

systemctl set-default graphical.target

Answer

systemctl isolate graphical.target

Answer

systemctl enable default.target --now

Answer

systemctl start graphical.target

A system administrator needs to troubleshoot a failing service named `httpd.service`.Which of the following commands provides the most direct and comprehensive way to view all log entries for only that specific service since the system last booted?

A system administrator needs to troubleshoot a failing service named `httpd.service`.
Which of the following commands provides the most direct and comprehensive way to view all log entries for only that specific service since the system last booted?