Top 30 DevOps Engineer Interview Questions & Answers for AWS Tools – 2025

DevOps engineers working with AWS tools are expected to handle CI/CD pipelines, infrastructure automation, monitoring, and more. These top 30 interview questions focus on AWS services commonly used in DevOps and real-world scenarios to help you prepare for 2025 job roles.

Foundational Questions

• 1. What is DevOps?
  DevOps is a set of practices that automate and integrate the processes between software development and IT teams to build, test, and release software faster and more reliably.
• 2. Name key AWS tools used in DevOps.
  AWS CodePipeline, CodeBuild, CodeDeploy, CodeCommit, CloudFormation, CloudWatch, ECS, EKS, Lambda, and IAM.
• 3. What is CI/CD in the context of AWS?
  Continuous Integration and Continuous Deployment using AWS tools to automate building, testing, and releasing code.
• 4. What is AWS CodePipeline?
  It's a CI/CD service to automate release pipelines for fast and reliable application and infrastructure updates.
• 5. What is AWS CodeDeploy?
  A service that automates code deployments to any instance, including Amazon EC2 and on-prem servers.

Infrastructure as Code (IaC)

• 6. What is AWS CloudFormation?
  It allows you to define infrastructure as code using JSON or YAML templates for repeatable deployments.
• 7. How is CloudFormation different from Terraform?
  CloudFormation is AWS-native; Terraform is cloud-agnostic and uses HCL for configuration.
• 8. How would you use CloudFormation for blue/green deployment?
  Create two stacks (blue and green), shift traffic between them using Route53 or Load Balancer when the green stack is validated.
• 9. How can you automate infrastructure provisioning in AWS?
  Using CloudFormation, CDK, or Terraform in CI/CD pipelines for full automation and repeatability.
• 10. What is AWS CDK?
  AWS Cloud Development Kit lets you define cloud infrastructure using programming languages like Python or TypeScript.

CI/CD & Deployment

• 11. How do you set up a CI/CD pipeline in AWS?
  Using CodeCommit (repo) → CodeBuild (build) → CodeDeploy (deploy) integrated via CodePipeline.
• 12. What is the role of IAM in CI/CD?
  IAM defines access permissions for services and pipelines. Secure roles and least-privilege access is crucial.
• 13. How do you roll back a failed deployment?
  CodeDeploy supports automatic rollback based on failure metrics or manual intervention using deployment revision history.
• 14. How do you handle secrets in AWS pipelines?
  Use AWS Secrets Manager or Systems Manager Parameter Store (with encryption) for managing sensitive data securely.
• 15. What is AWS CodeBuild?
  A fully managed continuous integration service to compile source code, run tests, and produce artifacts.

Containerization & Orchestration

• 16. How do you deploy containers using AWS?
  Use ECS, EKS, or Fargate with Docker images pushed to Amazon ECR (Elastic Container Registry).
• 17. What's the difference between ECS and EKS?
  ECS is AWS's own orchestration, while EKS is managed Kubernetes. ECS is simpler, EKS offers more flexibility.
• 18. What is AWS Fargate?
  A serverless compute engine for containers, eliminating the need to manage infrastructure.
• 19. How do you monitor container performance in AWS?
  Use CloudWatch metrics, logs, and AWS X-Ray. Fluent Bit or Prometheus/Grafana can also be integrated.
• 20. How do you scale containers automatically?
  Using ECS or EKS with Auto Scaling groups based on CloudWatch metrics like CPU and memory.

Monitoring & Security

• 21. What tools does AWS offer for monitoring?
  CloudWatch (logs, metrics, alarms), X-Ray (tracing), and CloudTrail (API activity logs).
• 22. How do you monitor a Lambda function?
  Use CloudWatch logs, custom metrics, and AWS X-Ray for tracing execution flow and debugging issues.
• 23. How do you manage cost in a DevOps environment?
  Enable billing alerts, use cost explorer, tag resources, and apply resource policies to shut down unused instances.
• 24. How do you enforce security compliance in pipelines?
  Integrate security scanning tools like SonarQube, Checkov, or AWS Inspector. Apply IAM policies and restrict privileges.
• 25. How do you set up centralized logging?
  Use CloudWatch Logs with log groups and streams, optionally send to S3 or integrate with ELK or OpenSearch.

Real-Time Scenarios

• 26. Scenario: CI/CD failed due to incorrect buildspec.yml. What would you do?
  Check the build logs in CodeBuild, fix the YAML syntax or paths, validate with local builds, and re-trigger the pipeline.
• 27. Scenario: ECS service isn't scaling. How do you troubleshoot?
  Check ECS service metrics, CloudWatch alarms, task definitions, and scaling policies. Validate IAM roles too.
• 28. Scenario: Deployment succeeded but app is not reachable. What steps do you take?
  Check security groups, target group health, load balancer config, app logs, and DNS resolution via Route53.
• 29. Scenario: You need zero downtime deployment. What strategy do you use?
  Use blue/green or canary deployment via CodeDeploy with traffic shifting policies.
• 30. Scenario: Secrets are leaking in logs. What’s your mitigation plan?
  Immediately rotate secrets using Secrets Manager, remove them from logs, and audit roles with access to those logs.