DevOps Interview Questions 2025 - Top 100 with Answers

Here are 100 Essential DevOps Interview Questions & Answers for 2025, categorized for structured learning. Master these to ace your DevOps interviews!

Core Concepts & Culture (1-10)

1. What is DevOps?

A cultural and technical movement emphasizing collaboration, automation, and continuous delivery to improve software flow.

2. Explain the CALMS model.

Culture, Automation, Lean, Measurement, Sharing.

3. What is DevSecOps?

Integrating security practices into the DevOps pipeline from the start.

4. What is GitOps?

Using Git as the single source of truth for declarative infrastructure and applications.

5. Explain "Shift-Left" testing.

Incorporating testing earlier in the development cycle.

6. What is "Toil" in SRE terms?

Manual, repetitive operational work that scales linearly with service growth.

7. What is a "Blame-Free Post-Mortem"?

A focus on process and system failures, not individual blame.

8. Define "Immutable Infrastructure."

Servers are never modified after deployment; replaced entirely with new versions.

9. What is "Infrastructure as Code" (IaC)?

Managing infrastructure through machine-readable definition files.

10. Explain the "12-Factor App" methodology.

Best practices for building SaaS apps (e.g., config in environment, stateless processes).

Linux & Scripting (11-20)

11. How to check disk space in Linux?

df -h

12. How to find a file named "app.log"?

find / -name app.log 2>/dev/null

13. How to check memory usage?

free -m or htop

14. Explain awk '{print $1} ' file.txt

Prints the first column of each line in file.txt.

15. What does chmod 755 file.sh do?

Gives user rwx, group rx, others rx.

16. How to run a process in the background?

Append & or use screen/tmux.

17. What is a shebang line?

#!/bin/bash – tells the OS which interpreter to use.

18. How to kill a process on port 3000?

sudo lsof -ti:3000 | xargs kill -9

19. Explain grep -r "error" /var/log/

Recursively searches for "error" in /var/log.

20. What is sudo?

Execute a command with superuser privileges.

Git & Version Control (21-30)

21. Difference between git merge and git rebase?

Merge creates a new commit; rebase rewrites commit history onto another branch.

22. What is a .gitignore file?

Specifies intentionally untracked files to ignore.

23. Explain git cherry-pick.

Applies a specific commit from one branch to another.

24. How to undo the last commit?

git reset --soft HEAD~1 (keeps changes) or --hard (discards changes).

25. What is git stash?

Temporarily shelves changes to work on something else.

26. Difference between git fetch and git pull?

Fetch downloads changes; fetch + merge = pull.

27. How to create a new branch?

git checkout -b new-branch

28. What is a Git hook?

Scripts that run automatically before/after events like commit or push.

29. Explain git bisect.

Binary search to find which commit introduced a bug.

30. How to squash commits?

git rebase -i HEAD~n then mark commits as squash.

📚 Complete Guide Includes:

✅ CI/CD (Questions 31-40)
✅ Docker & Containers (Questions 41-50)
✅ Kubernetes (Questions 51-65)
✅ Cloud & IaC (Questions 66-75)
✅ Monitoring & Logging (Questions 76-85)
✅ Security - DevSecOps (Questions 86-95)
✅ Scripting & Problem-Solving (Questions 96-100)

Download the complete PDF with all 100 questions when you enroll in our DevOps Master Program!

CI/CD (31-40) - Sample Questions

31. What is Jenkins Pipeline?

A suite of plugins for implementing CI/CD as code (Jenkinsfile).

35. What is a "Multibranch Pipeline"?

Automatically creates pipelines for each branch in a repository.

36. Explain Blue-Green Deployment.

Two identical environments; switch traffic from old (blue) to new (green).

Docker & Containers (41-50) - Sample Questions

41. What is a Docker image?

A read-only template with instructions for creating a container.

42. Difference between CMD and ENTRYPOINT?

ENTRYPOINT sets the executable; CMD sets default arguments.

45. What is a multi-stage Docker build?

Uses multiple FROM statements to keep final image small.

Kubernetes (51-65) - Sample Questions

51. What is a Pod?

Smallest deployable unit; one or more containers sharing network/storage.

52. Explain Deployment vs. StatefulSet.

Deployment for stateless apps; StatefulSet for stateful apps with stable identities.

60. What is Helm?

Package manager for Kubernetes (charts).

💡 Pro Tip for 2025:

Combine tool knowledge with real-world scenarios. Practice explaining concepts as if to a colleague. Your ability to troubleshoot and communicate will set you apart. Good luck!

🎯 Interview Preparation Tips:

✅ Practice hands-on with each tool mentioned
✅ Build real projects to demonstrate your knowledge
✅ Prepare to explain your thought process, not just answers
✅ Review common troubleshooting scenarios
✅ Stay updated with latest DevOps trends