- A
The 'systemctl enable' command only creates symlinks; a separate 'systemctl start' must be run after enable.
Why wrong: Enable is for boot start, not immediate start; but the service should start at boot.
- B
The service depends on a target that is not reached before the service starts, and 'Restart=on-failure' does not retry the start if the condition is not met.
With After=network.target, the service may start before network is fully ready; on-failure only restarts if the service exits with non-zero, but if the start fails due to a condition (e.g., network not ready), the service may not be restarted. Using 'Restart=always' or 'RestartSec' can help.
- C
The 'systemctl enable' command was not run as root.
Why wrong: Even if not root, it would have given an error; but the command succeeded as stated.
- D
The unit file has a syntax error that prevents systemd from parsing it.
Why wrong: If there were a syntax error, manual start would also fail.
Quick Answer
The answer is that the service lacks a requirement directive, so systemd only respects the ordering from After=network.target without ensuring the target is actually active. This is the most likely cause when a systemd service fails to start after reboot despite being enabled, because After= merely schedules the start order but does not pull in the target as a dependency. If the network target isn’t fully reached when myapp.service starts, systemd attempts the ExecStart once, and Restart=on-failure only retries if the process exits with a non-zero code after a successful start—it does not reattempt a failed initial launch due to unmet conditions. On the LFCS exam, this tests your understanding of the critical difference between ordering and requirement directives; a common trap is assuming After= guarantees the target is up. To fix it, add Requires=network.target or Wants=network.target to the [Unit] section. Memory tip: “After orders the line, Requires makes it shine.”
LFCS Service Configuration Practice Question
This LFCS practice question tests your understanding of service configuration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company runs a critical web application on a Linux server. The application is managed by a systemd service called 'myapp.service'. Recently, after a scheduled maintenance reboot, the service failed to start automatically. The administrator manually started it with 'systemctl start myapp' and it ran fine. The unit file is located at /etc/systemd/system/myapp.service and contains: [Unit] Description=MyApp After=network.target [Service] ExecStart=/usr/local/bin/myapp Restart=on-failure [Install] WantedBy=multi-user.target. The administrator wants to ensure the service starts automatically after future reboots. However, after running 'systemctl enable myapp', the service still didn't start after the next reboot. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The service depends on a target that is not reached before the service starts, and 'Restart=on-failure' does not retry the start if the condition is not met.
Option B is correct because the 'After=network.target' directive only specifies ordering, not a requirement. If the network target is not fully reached before the service starts, systemd will attempt to start the service once and, if it fails, 'Restart=on-failure' will restart it only if the start was successful but the process later exits with a failure. It does not retry the initial start if a dependency condition is not met. The service must have 'Requires=network.target' or 'Wants=network.target' to ensure the target is active before the service starts.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The 'systemctl enable' command only creates symlinks; a separate 'systemctl start' must be run after enable.
Why it's wrong here
Enable is for boot start, not immediate start; but the service should start at boot.
- ✓
The service depends on a target that is not reached before the service starts, and 'Restart=on-failure' does not retry the start if the condition is not met.
Why this is correct
With After=network.target, the service may start before network is fully ready; on-failure only restarts if the service exits with non-zero, but if the start fails due to a condition (e.g., network not ready), the service may not be restarted. Using 'Restart=always' or 'RestartSec' can help.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The 'systemctl enable' command was not run as root.
Why it's wrong here
Even if not root, it would have given an error; but the command succeeded as stated.
- ✗
The unit file has a syntax error that prevents systemd from parsing it.
Why it's wrong here
If there were a syntax error, manual start would also fail.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse 'After=' with a dependency directive, assuming ordering implies requirement, and overlook that 'Restart=on-failure' only applies to runtime failures, not initial start failures due to unmet conditions.
Trap categories for this question
Command / output trap
Even if not root, it would have given an error; but the command succeeded as stated.
Detailed technical explanation
How to think about this question
In systemd, 'After=' only orders the start sequence but does not create a dependency; the service can start before the specified unit is fully up. To enforce a dependency, you must use 'Requires=' or 'Wants='. 'Restart=on-failure' only triggers restarts after the service has successfully started and then exits with a non-zero code or is killed; it does not retry the initial start if the service fails due to unmet dependencies. A real-world scenario is a web application that needs networking; if 'network.target' is not reached (e.g., due to a slow DHCP), the service starts and fails immediately, and 'Restart=on-failure' does not help because the start itself failed.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the LFCS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this LFCS question test?
Service Configuration — This question tests Service Configuration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The service depends on a target that is not reached before the service starts, and 'Restart=on-failure' does not retry the start if the condition is not met. — Option B is correct because the 'After=network.target' directive only specifies ordering, not a requirement. If the network target is not fully reached before the service starts, systemd will attempt to start the service once and, if it fails, 'Restart=on-failure' will restart it only if the start was successful but the process later exits with a failure. It does not retry the initial start if a dependency condition is not met. The service must have 'Requires=network.target' or 'Wants=network.target' to ensure the target is active before the service starts.
What should I do if I get this LFCS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
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