Linux Systems Administrator Interview Questions UK: 8 Real Questions and What Interviewers Want

Applying for a Linux Systems Administrator job in the UK? Here is what you are likely to be asked. These questions come from our Linux Systems Administrator question bank of 16 questions, written for UK employers at mid-level level.

Eight Linux Systems Administrator interview questions, and what the interviewer is thinking

1. A Linux server is running slowly. Walk me through how you would diagnose it from the command line.

Why they ask: The classic Linux admin question, testing a methodical command-line approach.

2. Explain Linux file permissions, including setuid, the sticky bit and how ACLs extend the standard model.

Why they ask: To check core security and access control knowledge.

3. How do you manage services and troubleshoot a service that fails to start under systemd?

Why they ask: To test day-to-day systemd competence.

4. How would you manage disk storage on a Linux server using LVM, and how would you extend a full filesystem without downtime?

Why they ask: To check storage management skills.

5. How do you automate repetitive Linux administration tasks, and what are the strengths of Bash compared with tools like Ansible?

Why they ask: To test automation mindset and tooling choices.

6. It is 2am and you are on call. A production web server has run out of disk space and the application has stopped. What do you do?

Why they ask: To test calm incident handling and practical judgement.

7. Tell me about a time you automated a manual process and what difference it made.

Why they ask: To check initiative and measurable improvement.

8. What attracts you to Linux system administration, and how do you keep your skills current?

Why they ask: To check genuine interest and development habits.

A sample answer to question 1

A Linux server is running slowly. Walk me through how you would diagnose it from the command line.

I would begin with uptime to see the load averages, then top or htop to see which processes are consuming CPU and memory, and whether the wait percentage points to disk contention. Next I would check memory with free -h and look for swapping using vmstat 1. For disk I would use df -h and df -i, since a full filesystem or inode exhaustion causes strange symptoms, then iostat -x or iotop to identify heavy I/O. For network issues I would use ss -tulpn, and check for saturation with iftop or sar. I would also read the logs, with journalctl -xe and dmesg, looking for out-of-memory kills or hardware errors. Once I identify the culprit, I would decide on a fix, such as tuning a service, killing a runaway job or adding resource, and document it. I would also check monitoring history to see when it began and what changed.

Common mistake to avoid: Restarting services before diagnosing; Ignoring inode exhaustion

Want the rest?

Full model answers, key points and common mistakes for all 16 questions are on the Linux Systems Administrator interview questions page. The first five are free, no sign-up needed.