Top 50 Advanced DevOps Interview Questions (2026 Guide)

By Manish saini

🟢 Basic Level 

General Concepts

  1. What is DevOps and why is it important?
  2. What is the difference between DevOps and Agile?
  3. Explain the DevOps lifecycle (Plan → Code → Build → Test → Release → Deploy → Operate → Monitor).
  4. What is CI/CD? How do they differ?
  5. What is the difference between Continuous Delivery and Continuous Deployment?



Version Control
  1. What is Git? How is it different from SVN?
  2. What is the difference between git merge and git rebase?
  3. What is a pull request / merge request?
  4. How do you resolve a merge conflict in Git?


Linux/OS Basics
  1. What are inodes in Linux?
  2. How do you check disk usage in Linux? (df, du)
  3. What is the difference between a process and a thread?
  4. What does chmod 755 mean?
  5. How do you check running processes? (ps, top, htop)

🟡 Intermediate Level
CI/CD & Automation

  1. What tools have you used for CI/CD? (Jenkins, GitHub Actions, GitLab CI, CircleCI)
  2. Explain a Jenkins pipeline. What is a Jenkinsfile?
  3. What is the difference between a declarative and scripted pipeline in Jenkins?
  4. How do you handle secrets/credentials in a CI/CD pipeline?
  5. What is a build artifact? How do you manage them?

Containerization
  1. What is Docker? How does it differ from a virtual machine?
  2. Explain the difference between a Docker image and a container.
  3. What is a Dockerfile? Walk me through writing one.
  4. What is Docker Compose and when would you use it?
  5. How do Docker volumes work? Why are they needed?
  6. What is the difference between CMD and ENTRYPOINT in a Dockerfile?

Configuration Management
  1. What is Infrastructure as Code (IaC)?
  2. What is the difference between Ansible, Chef, and Puppet?
  3. What is an Ansible playbook? What is an inventory file?
  4. What are idempotent operations? Why do they matter in IaC?

Cloud Basics
  1. What is the difference between IaaS, PaaS, and SaaS?
  2. What is auto-scaling? How does it work in AWS/Azure/GCP?
  3. What is an S3 bucket? What are common use cases?
  4. What is a VPC? What are subnets, security groups, and NACLs?

🔴 Advanced Level
Kubernetes

  1. What is Kubernetes and why is it used?
  2. Explain the Kubernetes architecture (Master Node, Worker Node, etcd, API Server, Scheduler, Controller Manager, Kubelet, Kube-proxy).
  3. What is the difference between a Pod, Deployment, ReplicaSet, and StatefulSet?
  4. What is a Kubernetes Service? Explain ClusterIP, NodePort, and LoadBalancer.
  5. What are ConfigMaps and Secrets in Kubernetes?
  6. How does Kubernetes handle rolling updates and rollbacks?
  7. What is a Helm chart? When would you use it?
  8. What is a Kubernetes Ingress? How does it differ from a Service?
  9. How do you horizontally scale pods in Kubernetes? (HPA)
  10. What is the difference between Liveness and Readiness probes?

Terraform / IaC Advanced
  1. What is Terraform state? Why is it important?
  2. What is the difference between terraform plan and terraform apply?
  3. How do you manage Terraform state in a team? (remote backends like S3 + DynamoDB)
  4. What are Terraform modules? Why use them?
  5. What is terraform import used for?
  6. How do you handle sensitive data in Terraform?

Monitoring & Observability
  1. What is the difference between monitoring and observability?
  2. What are the three pillars of observability? (Logs, Metrics, Traces)
  3. What tools have you used for monitoring? (Prometheus, Grafana, Datadog, ELK Stack)
  4. What is a Prometheus exporter? What is a scrape interval?
  5. How do you set up alerting with Prometheus + Alertmanager?
  6. What is distributed tracing? Have you used Jaeger or Zipkin?
  7. What is an SLO, SLI, and SLA? How do you define them?

Networking & Security
  1. What is a reverse proxy? How is it different from a load balancer?
  2. What is mTLS? Why is it used in microservices?
  3. What is a service mesh? (e.g., Istio, Linkerd)
  4. How do you secure a Kubernetes cluster?
  5. What is RBAC in Kubernetes?
  6. What is a zero-trust security model?
  7. How do you scan Docker images for vulnerabilities? (Trivy, Snyk)

High Availability & Scalability
  1. How would you design a highly available architecture on AWS?
  2. What is the CAP theorem? How does it apply to distributed systems?
  3. What is the difference between horizontal and vertical scaling?
  4. What are blue-green deployments and canary deployments?
  5. What is a circuit breaker pattern? Why is it important in microservices?
  6. How do you handle database migrations in a zero-downtime deployment?

🧠 Scenario-Based Questions
  1. Your production deployment failed. How do you rollback quickly?
  2. A container is running but the application is not responding. How do you debug it?
  3. Your CI/CD pipeline takes 45 minutes to run. How would you optimize it?
  4. You need to migrate a monolithic app to microservices. What is your approach?
  5. How would you implement GitOps for your infrastructure?
  6. A Kubernetes node is NotReady. Walk me through your troubleshooting steps.



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