Comprehensive DevOps Q&A for Aspiring Professionals

 


Top 45 DevOps Interview Questions and Answers


1. What is DevOps?

DevOps is a cultural and technical movement that combines development (Dev) and operations (Ops) to improve collaboration, automate workflows, and deliver software faster and more reliably.

2. What are the key principles of DevOps?

  1. Collaboration and communication.

  2. Automation of processes.

  3. Continuous integration and delivery.

  4. Monitoring and feedback.

  5. Infrastructure as Code (IaC).

3. What is CI/CD?

  • CI (Continuous Integration): Developers frequently merge code changes into a shared repository, and automated builds and tests are run.

  • CD (Continuous Delivery/Deployment): The code is automatically deployed to production or staging environments after passing CI.

4. What is Infrastructure as Code (IaC)?

IaC is the practice of managing and provisioning infrastructure through code instead of manual processes, using tools like Terraform, Ansible, and CloudFormation.

5. What are some popular DevOps tools?

  • CI/CD: Jenkins, GitHub Actions, GitLab CI

  • Containerization: Docker

  • Orchestration: Kubernetes

  • IaC: Terraform, Ansible

  • Monitoring: Prometheus, Grafana

  • Version Control: Git

6. Explain the differences between Agile and DevOps.

  • Agile: Focuses on iterative software development.

  • DevOps: Focuses on software delivery and operational efficiency.

7. What is version control, and why is it important?

Version control systems track changes to code, enabling teams to collaborate effectively and manage code versions. Example: Git.

8. How does Git work in DevOps?

Git is a distributed version control system used to manage source code. It supports features like branching, merging, and version tracking.

9. What is the difference between Docker and a virtual machine (VM)?

  • Docker: Lightweight, shares the host OS kernel, and uses containers.

  • VM: Heavyweight, emulates entire OS instances.

10. What are microservices?

Microservices are an architectural style where applications are built as a collection of small, independent, and loosely coupled services.

11. What is Kubernetes?

Kubernetes is an open-source container orchestration tool used to deploy, manage, and scale containerized applications.

12. Explain a CI/CD pipeline.

A CI/CD pipeline automates code building, testing, and deployment. Example stages:

  1. Source: Pull code from Git.

  2. Build: Compile code.

  3. Test: Run automated tests.

  4. Deploy: Deploy code to environments.

13. What is Jenkins?

Jenkins is an open-source automation server used to build, test, and deploy software projects.

14. What is a build tool?

A build tool compiles source code into executable code. Examples: Maven, Gradle.

15. What is the difference between continuous delivery and continuous deployment?

  • Continuous Delivery: Code is ready for release but requires manual approval.

  • Continuous Deployment: Code is automatically deployed to production.

16. How do you secure a CI/CD pipeline?

  1. Use secure credentials management.

  2. Encrypt sensitive data.

  3. Implement role-based access control.

  4. Regularly update dependencies.

17. What is a container?

A container is a lightweight, portable unit that packages an application with its dependencies, ensuring consistency across environments.

18. How does Docker work?

Docker uses containerization technology to package applications and dependencies into a single container image that can run anywhere.

19. What is a reverse proxy?

A reverse proxy is a server that routes client requests to backend servers, often used for load balancing, caching, or security.

20. What is Ansible?

Ansible is an open-source configuration management and automation tool used to manage servers and deploy applications.

21. What is Terraform?

Terraform is an IaC tool that allows you to define and provision infrastructure using a high-level configuration language.

22. What is the ELK stack?

ELK stands for Elasticsearch, Logstash, and Kibana, a set of tools for log aggregation, processing, and visualization.

23. How do you handle environment-specific configurations in CI/CD?

Use environment variables or configuration management tools like Ansible or Consul.

24. What is blue-green deployment?

Blue-green deployment is a strategy where two identical environments (blue and green) are used to minimize downtime during releases.

25. What is a canary deployment?

Canary deployment releases a new version of software to a small subset of users before a full rollout.

26. How do you monitor applications in DevOps?

Use monitoring tools like Prometheus, Grafana, or Datadog to track application performance and health.

27. What is the purpose of a load balancer?

A load balancer distributes incoming traffic across multiple servers to ensure reliability and scalability.

28. What is a configuration management tool?

Tools like Chef, Puppet, and Ansible are used to automate and manage system configurations.

29. What are artifacts in DevOps?

Artifacts are the packaged versions of software components, such as .jar or .war files, stored in repositories like Nexus or Artifactory.

30. What is a rolling deployment?

A rolling deployment updates a subset of servers at a time, reducing downtime.

31. How do you handle failed deployments?

  1. Use automated rollback mechanisms.

  2. Analyze logs for root cause.

  3. Deploy fixes via CI/CD.

32. What is Prometheus?

Prometheus is an open-source monitoring tool that collects metrics and supports alerting.

33. What is Grafana?

Grafana is a visualization tool used to create dashboards for metrics and logs.

34. How does DNS work in DevOps?

DNS resolves domain names to IP addresses, enabling communication between services and users.

35. What is GitOps?

GitOps is a DevOps practice where Git repositories are the source of truth for CI/CD pipelines and infrastructure.

36. How do you optimize CI/CD pipelines?

  1. Use parallel builds and tests.

  2. Cache dependencies.

  3. Automate everything.

  4. Monitor pipeline performance.

37. What is a webhook?

A webhook is an HTTP callback triggered by an event, commonly used in CI/CD systems.

38. What is a service mesh?

A service mesh manages communication between microservices, providing features like traffic control and security. Example: Istio.

39. What is immutable infrastructure?

Immutable infrastructure ensures that servers are not modified after deployment; changes require redeployment of new instances.

40. How do you scale applications?

  1. Horizontal scaling: Add more instances.

  2. Vertical scaling: Add resources to existing instances.

  3. Use load balancers and auto-scaling groups.

41. What are pods in Kubernetes?

Pods are the smallest deployable units in Kubernetes, containing one or more containers.

42. What is Helm?

Helm is a package manager for Kubernetes used to deploy applications as Helm charts.

43. What is a cluster in Kubernetes?

A cluster consists of multiple nodes managed by Kubernetes, used to deploy and manage containerized applications.

44. What is the 12-factor app methodology?

A set of best practices for building cloud-native applications, focusing on factors like scalability, configuration, and processes.

45. How do you ensure high availability in DevOps?

  1. Use load balancers.

  2. Deploy across multiple regions.

  3. Monitor system health.

Location: Bengaluru, Karnataka, India

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