DevOps Interview Questions 2025

DevOps is a set of practices, philosophies, and cultural philosophies that aim to unify software development (Dev) and IT operations (Ops). The primary goal of DevOps is to shorten the development lifecycle, deliver high-quality software continuously, and improve collaboration between development and operations teams.

What is DevOps?

  • DevOps is not just a set of tools or technologies; it's a cultural shift that emphasizes collaboration, automation, and continuous improvement.
  • It bridges the gap between development (building software) and operations (running and maintaining software).
  • DevOps focuses on automating processes, improving efficiency, and enabling faster delivery of applications.

Why DevOps?

  • Faster Delivery: Automating processes allows teams to release software more frequently and reliably.
  • Improved Collaboration: Breaks down silos between development and operations teams.
  • Enhanced Quality: Continuous testing and monitoring ensure higher-quality software.
  • Scalability: Infrastructure as Code (IaC) and containerization enable scalable and repeatable deployments.
  • Reliability: Monitoring and logging tools help identify and resolve issues quickly.

Key Principles of DevOps

  1. Automation: Automate repetitive tasks like testing, deployments, and infrastructure provisioning.
  2. Continuous Integration (CI): Merge code changes frequently and test them automatically.
  3. Continuous Delivery (CD): Ensure software can be released to production at any time.
  4. Monitoring and Logging: Track application performance and errors in real-time.
  5. Collaboration: Foster a culture of shared responsibility between teams.
  6. Infrastructure as Code (IaC): Manage infrastructure using code for consistency and scalability.

DevOps Lifecycle

The DevOps lifecycle consists of the following stages:

  1. Plan: Define requirements and plan the development process.
  2. Code: Write and review code collaboratively.
  3. Build: Compile and build the application.
  4. Test: Automate testing to ensure quality.
  5. Release: Deploy the application to production.
  6. Deploy: Use CI/CD pipelines for seamless deployments.
  7. Operate: Monitor and manage the application in production.
  8. Monitor: Continuously monitor performance and gather feedback.
  9. Feedback: Use insights to improve the next iteration.

Core DevOps Concepts

  1. What is DevOps and how does it differ from traditional development methodologies?
  2. Explain the DevOps lifecycle.
  3. What are the key principles of DevOps?
  4. What is CAMS in DevOps?
  5. What are the key components of DevOps?
  6. What is the difference between Agile and DevOps?
  7. What are the benefits of implementing DevOps practices?
  8. What is the role of a DevOps engineer?
  9. What is the difference between DevOps and SRE?
  10. What are the key metrics in DevOps (KPIs)?
  11. What is "shift left" in DevOps?
  12. Mention what the key aspects or principles behind DevOps are?
  13. What are the core operations of DevOps with application development and with infrastructure?
  14. What are the prerequisites for the implementation of DevOps?
  15. Name some best practices which should be followed for DevOps success.
  16. Name some of the areas where DevOps are implemented.

Version Control

  1. What is Git, and why is it used?
  2. Explain Git branching strategies (Git Flow, GitHub Flow, Trunk-Based).
  3. What is a Git merge conflict, and how do you resolve it?
  4. What is git rebase vs. git merge?
  5. How do you revert a Git commit?
  6. What is a .gitignore file?
  7. How do you squash commits in Git?
  8. What is Git cherry-pick?
  9. Explain Git hooks.
  10. How do you handle large files in Git (Git LFS)?
  11. What version control systems have you used? What are their pros and cons?
  12. Explain how you would handle revision (version) control?
  13. Give some benefits of using Version Control systems.
  14. Explain Git Bisect.
  15. Explain SubGit tool.

CI/CD

  1. What is Continuous Integration (CI) and Continuous Deployment (CD)?
  2. What is the difference between CI and CD?
  3. What is the difference between continuous delivery and continuous deployment?
  4. What are the stages of a CI/CD pipeline?
  5. Name popular CI/CD tools (Jenkins, GitLab CI, GitHub Actions, CircleCI).
  6. How do you handle failed builds in CI?
  7. What is a Jenkins pipeline?
  8. How do you secure a CI/CD pipeline?
  9. Explain blue-green deployment methodology.
  10. What is canary deployment and when would you use it?
  11. Explain the term 'Canary Release'.
  12. What is a rolling deployment?
  13. How do you implement CI/CD for microservices?
  14. How do you handle rollbacks in case of failed deployments?
  15. Explain how you would set up a CI/CD pipeline for a typical application.
  16. Explain Blue/Green Deployment Pattern.
  17. What is the build?
  18. Explain your experience with CI/CD tools like Jenkins, GitLab CI, or GitHub Actions.

Configuration Management & Infrastructure as Code

  1. What is Infrastructure as Code (IaC)? Why is it important?
  2. Explain how "Infrastructure code" is processed or executed in AWS?
  3. Compare Terraform vs. Ansible vs. CloudFormation.
  4. What are Terraform modules?
  5. How do you manage Terraform state files securely?
  6. What is Ansible, and how does it work?
  7. Explain Ansible playbooks, roles, and inventories.
  8. What is idempotency in Ansible?
  9. How do you handle secrets in Ansible?
  10. What is Puppet/Chef, and how do they differ from Ansible?
  11. What is Pulumi, and how is it different from Terraform?
  12. What is configuration management? Name some popular tools.
  13. What is Puppet?
  14. What is Chef?
  15. Explain your experience with Ansible/Puppet/Chef/other configuration management tools.
  16. What is GitOps and how is it beneficial?
  17. How do you deal with configuration drift?
  18. What is your experience with Infrastructure as Code testing?

Containerization

  1. What are containers and their benefits in a DevOps workflow?
  2. What is Docker, and how does it work?
  3. Explain Docker architecture (Docker Engine, Images, Containers).
  4. What is the difference between a Docker image and a container?
  5. How do you reduce Docker image size?
  6. What is a multi-stage build in Docker?
  7. How do you manage Docker volumes?
  8. What is Docker Compose?
  9. How do you secure Docker containers?
  10. What is Docker Swarm?
  11. How do you debug a crashing Docker container?
  12. How do you optimize container images for production?
  13. Name two tools which are used for Docker networking.

Kubernetes and Orchestration

  1. What is Kubernetes and what problems does it solve?
  2. Explain Kubernetes architecture (Master & Worker Nodes).
  3. What is a Pod in Kubernetes?
  4. What are Deployments, ReplicaSets, and StatefulSets?
  5. How do Kubernetes Services work (ClusterIP, NodePort, LoadBalancer)?
  6. What is a ConfigMap and Secret in Kubernetes?
  7. How do you scale applications in Kubernetes?
  8. What is Helm, and why is it used?
  9. How do you debug a failing Pod?
  10. What is a Kubernetes Operator?
  11. How would you secure Kubernetes clusters?
  12. Describe your experience with containerization orchestration platforms.
  13. How do you manage state in containerized applications?

Cloud Computing

  1. What are the key AWS services for DevOps?
  2. Explain AWS ECS vs. EKS vs. Fargate.
  3. What is AWS Lambda, and how does it fit into DevOps?
  4. How do you automate AWS infrastructure?
  5. What is AWS CloudFormation?
  6. What is Azure DevOps?
  7. Explain GCP's CI/CD tools (Cloud Build, GKE).
  8. What is serverless computing?
  9. How do you secure cloud infrastructure?
  10. What is multi-cloud DevOps?
  11. What is your experience with cloud providers (AWS, Azure, GCP)?
  12. Name a few cloud platforms which are used for DevOps Implementation.
  13. What is your experience with serverless architecture?
  14. What is the easiest method to build a small cloud?

Monitoring & Logging

  1. What is the difference between monitoring and logging?
  2. Name popular monitoring tools (Prometheus, Grafana, Nagios, Datadog).
  3. What is APM (Application Performance Monitoring)?
  4. How do you set up alerts in Prometheus?
  5. What is ELK Stack (Elasticsearch, Logstash, Kibana)?
  6. How do you debug high CPU usage in a server?
  7. What is distributed tracing?
  8. What are the key metrics to monitor in Kubernetes?
  9. How do you handle log rotation?
  10. What is OpenTelemetry?
  11. What monitoring and logging tools have you worked with? How do you use them?
  12. Name some important network monitoring tools.
  13. What metrics do you consider essential to monitor in a production environment?
  14. What is your experience with observability tools and practices?
  15. Explain the concept of infrastructure monitoring.

Security (DevSecOps)

  1. What is DevSecOps?
  2. How do you ensure security in a DevOps environment?
  3. How do you implement security in CI/CD?
  4. What is SAST, DAST, and IAST?
  5. How do you handle secrets management in a CI/CD pipeline?
  6. What is RBAC in Kubernetes?
  7. How do you scan Docker images for vulnerabilities?
  8. What is a zero-trust security model?
  9. How do you secure API endpoints in microservices?
  10. What is compliance as code?
  11. How do you handle DDoS attacks in a DevOps environment?
  12. Explain two-factor authentication.
  13. How do you handle compliance requirements in DevOps?
  14. Explain the concept of shift-left security in DevOps.

Networking & Performance

  1. What is the OSI model?
  2. Explain TCP vs. UDP.
  3. What is a load balancer, and how does it work?
  4. What is an API Gateway?
  5. How do you troubleshoot network latency?
  6. What is DNS, and how does it work?
  7. What is the use of PTR in DNS?
  8. What is a CDN, and why is it used?
  9. How do you optimize database performance?
  10. What is gRPC, and how is it different from REST?
  11. How do you implement service discovery in microservices?
  12. What are the types of HTTP requests?
  13. What is service discovery and why is it important in microservices?
  14. How do you handle rate limiting and throttling in microservices?
  15. What is your approach to API versioning and backward compatibility?

Scripting & Automation

  1. What scripting languages are used in DevOps (Bash, Python, Go)?
  2. Explain which scripting language is most important for a DevOps engineer?
  3. How do you automate server provisioning?
  4. What is the difference between Bash and Python for automation?
  5. How do you schedule tasks in Linux (Cron)?
  6. What is YAML, and where is it used in DevOps?
  7. How do you parse JSON in a shell script?
  8. What is the difference between #!/bin/bash and #!/bin/sh?
  9. How do you debug a failing shell script?
  10. What is Python's subprocess module used for?
  11. How do you automate backups in Linux?
  12. At what instance have you used the SSH?

Databases in DevOps

  1. What is the difference between SQL and NoSQL?
  2. How do you manage database migrations in CI/CD?
  3. What strategies do you use for database migrations during deployments?
  4. How do you manage database schema changes without downtime?
  5. What is database replication?
  6. How do you optimize slow SQL queries?
  7. What is Redis, and how is it used in DevOps?
  8. How do you backup and restore a PostgreSQL database?
  9. What is database sharding?
  10. How do you monitor database performance?
  11. What is a connection pool?
  12. How do you implement database failover?
  13. What is Memcached?
  14. Mention some important features of Memcached?
  15. Is it possible to share a single instance of Memcache between multiple projects?
  16. You are having multiple Memcache servers, in which one of the Memcache servers fails, and it has your data, will it ever try to get key data from that one failed server?
  17. How can you minimize the Memcached server outages?
  18. How can you update Memcached when data changes?
  19. What is Dogpile effect? How can you prevent this effect?
  20. How Memcached should not be used?
  21. When a server gets shut down, does data stored in Memcached still available?
  22. What is the difference between Memcache and Memcached?

Troubleshooting & Debugging

  1. How do you troubleshoot a server that is running out of memory?
  2. What is strace, and how is it used for debugging?
  3. How do you check open ports on a Linux server?
  4. What is journalctl, and how is it used?
  5. How do you debug a slow API response?
  6. What is the difference between kill and kill -9?
  7. How do you analyze network traffic (tcpdump, Wireshark)?
  8. What is a core dump, and how do you analyze it?
  9. How do you troubleshoot a Kubernetes Pod stuck in CrashLoopBackOff?
  10. What is dmesg, and how is it useful?
  11. How would you troubleshoot a slow-performing application in production?
  12. Explain what you would check if a Linux-build-server suddenly starts getting slow?

Advanced DevOps & SRE Concepts

  1. What is Chaos Engineering?
  2. What is chaos engineering and why is it important?
  3. What is GitOps?
  4. How do you implement disaster recovery in DevOps?
  5. How do you implement disaster recovery in cloud environments?
  6. How do you implement disaster recovery testing?
  7. What is observability vs. monitoring?
  8. What is SLA, SLO, and SLI in SRE?
  9. How do you reduce MTTR (Mean Time to Recovery)?
  10. What is canary analysis?
  11. How do you implement auto-scaling in the cloud?
  12. What is auto-scaling and how would you implement it?
  13. What is a service mesh (Istio, Linkerd)?
  14. What is your experience with service mesh technology?
  15. How do you manage technical debt in DevOps?
  16. What is your approach to managing technical debt?
  17. What is microservices architecture?
  18. How do you approach capacity planning in cloud environments?
  19. How do you manage dependencies in your applications?
  20. What testing strategies do you implement in a CI/CD pipeline?
  21. How do you approach performance testing in your CI/CD pipeline?
  22. How do you approach zero-downtime deployments?
  23. What strategies do you use for reducing deployment downtime?
  24. What is your strategy for monitoring costs in cloud environments?
  25. What is your approach to automated regression testing?
  26. How do you implement feature flags in your applications?
  27. What are immutable infrastructure patterns and why are they useful?
  28. Explain the concept of idempotence in infrastructure automation.
  29. How do you implement high availability in your systems?
  30. What is your approach to incident management?
  31. What is a post-mortem meeting with reference to DevOps?
  32. What is CBD?
  33. Explain Pair Programming with reference to DevOps.
  34. Explain Resilience Test.
  35. Name three important DevOps KPIs.

Scenario-Based Questions

  1. A deployment failed in production. What steps do you take?
  2. How would you reduce CI pipeline execution time?
  3. Your Kubernetes cluster is running out of resources. How do you debug?
  4. How do you handle a sudden traffic spike?
  5. A server is hacked. What's your incident response plan?
  6. How do you migrate from VMs to Kubernetes?
  7. How do you implement zero-downtime deployments?
  8. Your Docker build is failing. How do you troubleshoot?
  9. How do you enforce compliance in a DevOps pipeline?
  10. How do you optimize cloud costs in a DevOps setup?

Linux/Ubuntu Questions

  1. Whether your video card can run Unity, how would you know?
  2. How to enable startup sound in Ubuntu?
  3. What is the quickest way to open an Ubuntu terminal in a particular directory?
  4. How can you get the current color of the current screen on the Ubuntu desktop?
  5. How do you create launchers on a desktop in Ubuntu?
  6. What is Vagrant?
  7. What types of testing are important to ensure that a new service is ready for production?
  8. Explain how DevOps is helpful to developers?

DevOps Roadmap

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