hardMultiple Select
XK0-006 Practice Question: Which THREE of the following are valid methods to…
Which THREE of the following are valid methods to troubleshoot a service that fails to start?
⚠ Common exam trap
Many candidates confuse general system health commands (like `df -h`) with service-specific troubleshooting methods, or they think `systemctl daemon-reload` is a diagnostic step when it only reloads configuration without providing error details.
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
✓
Run the service executable manually from the command line to see error output.
Option A is correct because running the service executable directly from the command line bypasses the service manager and surfaces stdout/stderr error messages that systemd may otherwise capture or suppress, making the actual failure reason visible. Option B is correct because journalctl queries the systemd journal, allowing you to inspect the unit's logged output and error messages (e.g., journalctl -u <service>) to identify why it failed to start. Option C is correct because a service often fails when its required dependencies (libraries, packages, or other units) are missing or not running, so verifying and starting those dependencies is a valid troubleshooting step. Option D is not a targeted method for a service startup failure; df -h only reports filesystem disk usage and is not specific to diagnosing why a particular service won't start. Option E is not a troubleshooting method for a failing service; systemctl daemon-reload only reloads unit file definitions after they are edited and does not diagnose or fix a service that fails to start.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Run the service executable manually from the command line to see error output.
Why this is correct
Running the executable directly bypasses systemd's abstraction, exposing startup errors on stderr that the service manager may swallow. This satisfies the stem's need to troubleshoot a service that fails to start by revealing the actual failure reason, such as missing libraries or permission faults.
- ✓
Review the service logs using journalctl.
Why this is correct
journalctl reads the systemd journal, which captures stdout, stderr and unit state transitions for the failed service. Querying it with -u against the unit name satisfies the stem's troubleshooting requirement by surfacing the precise exit code or error emitted during the start attempt.
- ✓
Check if the service's required dependencies are installed and running.
Why this is correct
A unit can fail because a required dependency, such as a database or socket unit, is absent or inactive. Verifying dependencies with systemctl list-dependencies or status satisfies the stem's troubleshooting requirement by confirming whether the service aborted due to an unmet Requires or After relationship.
- ✗
Run df -h to check disk space.
Why it's wrong here
df -h reports filesystem capacity and mount usage; it cannot reveal why a service failed to start, since that requires inspecting unit status, exit codes and journal logs. It is tempting because a full disk can cause startup failure, but it would be the correct choice only once disk exhaustion is the suspected cause.
- ✗
Reload the systemd daemon with systemctl daemon-reload.
Why it's wrong here
Reloading the systemd manager configuration only re-reads unit files after you edit them; it does not diagnose why a service fails to start. It is tempting because daemon-reload is required after modifying a unit, but that scenario assumes the unit itself was just changed, not that startup is failing for an unknown reason.
Go deeper
Related to this question
Learn chapter
System Services and Startup
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
Key term
systemctl
systemctl is the command-line tool used to inspect, start, stop, enable, or disable services managed by the systemd init system in Linux.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 practice question is part of Courseiva's free CompTIA 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 XK0-006 exam.