LFCS Service Configuration Practice Test 3 — 15 Questions

Question 1

A developer reports that a web application's logs are not being written to /var/log/myapp.log. The service runs as user 'myapp' and the log directory /var/log/myapp/ has permissions 755 owned by root. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The service user 'myapp' does not have write permission to the log directory.. The /var/log/myapp/ directory has permissions 755, which grants read and execute access to the 'others' category but not write. Since the service runs as user 'myapp', which is not the owner (root) and not in the root group, it falls under 'others' and thus lacks write permission. Without write permission on the directory, the service cannot create or write to /var/log/myapp.log, even if the file itself might have different permissions.

Answer

AppArmor is denying access.

Answer

SELinux is blocking the write.

Answer

The service is logging to systemd-journald instead of a file.

Question 2

Which THREE actions will affect the state of a systemd service that is currently running? (Choose three.)

Accepted Answer

systemctl kill myapp.service. Option A, `systemctl kill myapp.service`, is correct because it sends a signal (SIGTERM by default) to the service's processes, which changes the running state by terminating or signaling them. Option B, `systemctl reload myapp.service`, is correct because it triggers the service's ExecReload action, causing the running process to reload its configuration without stopping, thus affecting its runtime state. Option E, `systemctl stop myapp.service`, is correct because it explicitly stops the running service, transitioning it from active to inactive. Option C, `systemctl disable myapp.service`, only removes the service's autostart symlinks and does not affect a currently running instance. Option D, `systemctl daemon-reload`, only reloads systemd manager configuration and does not alter the state of any running service.

Answer

systemctl disable myapp.service

Answer

systemctl daemon-reload

Question 3

An administrator runs 'systemctl status sshd' and sees the output above. The administrator wants sshd to start automatically at boot. Which command should be used?

Accepted Answer

systemctl enable sshd. The `systemctl enable sshd` command creates the necessary symlinks in the systemd unit configuration directories (e.g., `/etc/systemd/system/multi-user.target.wants/`) so that the sshd service is started automatically at boot. This is the correct way to configure a service to start on boot in a systemd-based Linux distribution.

Answer

systemctl reenable sshd

Answer

systemctl mask sshd

Answer

systemctl start sshd

Question 4

A Linux administrator needs to temporarily stop a service named 'httpd' without disabling it from starting automatically on subsequent boots. Which command should be used?

Accepted Answer

systemctl stop httpd. The `systemctl stop httpd` command sends a SIGTERM signal to the main process of the httpd service, causing it to stop immediately. This action does not modify the service's enablement state, so the service will still start automatically on subsequent boots if it is enabled. This is the correct way to temporarily stop a service without altering its boot-time behavior.

Answer

systemctl mask httpd

Answer

systemctl disable httpd

Answer

systemctl kill httpd

Question 5

A system administrator needs to ensure the Apache httpd service starts automatically on system boot. Which command should they use?

Accepted Answer

systemctl enable httpd. The `systemctl enable httpd` command creates the necessary symlinks in the systemd unit configuration directories (typically `/etc/systemd/system/multi-user.target.wants/`) to ensure the Apache httpd service starts automatically at boot time. This is the correct approach because `enable` configures the service to be started on system startup, whereas `start` only runs it immediately without affecting boot behavior.

Answer

systemctl start httpd

Answer

systemctl disable httpd

Answer

systemctl reload httpd

Question 6

Which TWO commands can be used to check the status of the sshd service on a system using systemd?

Accepted Answer

systemctl is-active sshd. `systemctl is-active sshd` directly queries systemd to report whether the sshd service is currently in an active (running) state, returning a simple exit code and text output (e.g., 'active' or 'inactive'). Option E is correct because `systemctl status sshd` provides a comprehensive view of the service's current state, including whether it is active, its PID, recent log entries, and cgroup details, making it a standard command for checking service health on systemd-based systems.

Answer

systemctl list-units --type=service

Answer

systemctl is-enabled sshd

Answer

systemctl cat sshd

Question 7

Order the steps to create a new partition on a disk using fdisk.

Accepted Answer

Run 'n' to create a new partition, then specify partition type/number, then specify starting and ending sectors, then run 'w' to write changes.. The correct sequence to create a partition with fdisk is: first use 'n' to create a new partition, then specify the partition type and number (e.g., primary, logical) when prompted, then define the starting and ending sectors, and finally use 'w' to write the changes to the disk. Skipping or reordering steps can lead to errors or unintended configurations.

Answer

Run 'n' to create a new partition, then run 'w' to write changes, then specify partition type/number and sectors.

Answer

First specify partition type/number, then run 'n' to create a new partition, then specify sectors, then run 'w'.

Answer

Run 'n' to create a new partition, then specify sectors, then specify partition type/number, then run 'w'.

Question 8

Which command enables a service to start automatically at boot in a systemd-based system?

Accepted Answer

systemctl enable service. The `systemctl enable` command creates the necessary symlinks in the `/etc/systemd/system/` directory tree (typically `multi-user.target.wants/`) to ensure the specified service unit is started automatically when the system boots. This is the standard mechanism in systemd to configure a service for automatic startup at boot time.

Answer

systemctl set-default service

Answer

systemctl daemon-reload

Answer

systemctl start service

Question 9

A custom systemd service unit file has been created but the service fails to start with 'Exec format error'. What is the most likely cause?

Accepted Answer

The ExecStart command path is incorrect or missing shebang. The 'Exec format error' in systemd indicates that the binary or script specified in the ExecStart directive cannot be executed, typically because the path is incorrect, the file is not executable, or (most commonly) the script lacks a valid shebang line (e.g., #!/bin/bash). Without a shebang, the kernel does not know which interpreter to use, causing an execve() failure.

Answer

The unit file has incorrect permissions

Answer

The user does not have permission to start the service

Answer

The service is disabled

Question 10

An administrator configures a systemd service with Restart=on-failure and RestartSec=10. What happens if the service exits with a non-zero exit code?

Accepted Answer

It waits 10 seconds before restarting. When Restart=on-failure is set, systemd only restarts the service if it exits with a non-zero exit code or is terminated by a signal (excluding SIGHUP, SIGINT, SIGTERM, and SIGPIPE). The RestartSec=10 directive then introduces a 10-second delay before the restart attempt, preventing rapid restart loops and giving the system time to stabilize.

Answer

It restarts immediately

Answer

It retries infinitely regardless of exit code

Answer

It does not restart

Question 11

To check the details of a failed systemd service unit, including the last log entries, which command is most appropriate?

Accepted Answer

systemctl status service. `systemctl status service` is the most appropriate command because it displays the current state of the service unit, including whether it is active, failed, or inactive, along with the last several log entries from the journal for that unit. This provides both the failure status and the contextual log output needed to diagnose why the service failed, all in a single command.

Answer

systemctl list-units --failed

Answer

systemctl is-failed service

Answer

systemctl show service

Question 12

A service is configured to run as a specific user. Which directive in the [Service] section sets the user?

Accepted Answer

User. In systemd service units, the directive to specify the user under which the service process runs is `User=` within the `[Service]` section. This directive sets the Unix user account (by name or UID) that the service's main PID will execute as, ensuring proper privilege separation and security.

Answer

RunAs

Answer

Account

Answer

UserID

Question 13

Which systemd unit type is used to group services and other units together for boot execution?

Accepted Answer

target. In systemd, the 'target' unit type is designed to group services, sockets, timers, and other units into a logical synchronization point for boot execution. Targets do not execute code themselves but instead define dependencies (via Wants, Requires, and After directives) that ensure all associated units are started in the correct order to reach a desired system state, such as multi-user.target or graphical.target.

Answer

socket

Answer

timer

Answer

service

Question 14

Which TWO directives are typically used in a systemd service unit file to configure dependencies?

Accepted Answer

Wants. In a systemd unit file, Wants= (option B) and Requires= (option E) are dependency directives that pull in other units: Wants= establishes a weak dependency where the listed units are started if possible but failure does not stop this unit, while Requires= establishes a strong dependency where the listed units must be activated successfully or this unit fails. Both belong to the [Unit] section and define which other units are needed, which is exactly what the question asks. By contrast, After= (option A) and Before= (option C) only control ordering — they specify start/stop sequence relative to other units but do not create a dependency that pulls those units in. Alias= (option D) merely provides an alternative name for the unit and has nothing to do with dependencies.

Answer

After

Answer

Before

Answer

Alias

Question 15

Which THREE of the following are valid systemd unit types?

Accepted Answer

target. Option C (target) is a valid systemd unit type: targets group other units and synchronize boot, replacing SysV runlevels (e.g., multi-user.target). Option D (socket) is valid: socket units describe an IPC or network socket that systemd listens on and activates the corresponding service via socket activation. Option E (service) is valid: service units define and control daemons or oneshot processes managed by systemd (e.g., sshd.service). Options A (notification) and B (startup) are not systemd unit types; notification is not a unit type at all, and startup is not a recognized unit suffix, whereas real types include service, socket, target, device, mount, automount, swap, timer, path, slice, and scope.

Answer

notification

Answer

startup