Cloud engineer interview questions

Cloud engineer interview questions and answers

Cloud interviews check that you can design, secure and run systems on AWS or Azure - and keep the bill under control. These are the questions asked most, with what each one checks.

What to revise before the interview

  • Compute: EC2/VMs, containers, serverless (Lambda/Functions)
  • Storage: S3/Blob, block storage, storage classes
  • Networking: VPC, subnets, route tables, security groups
  • IAM: users, roles, policies, least privilege
  • Load balancers and auto scaling
  • High availability across availability zones
  • Databases: RDS, DynamoDB
  • Cost optimisation and tagging

  1. 1.What are IaaS, PaaS and SaaS?

    What they're checking
    Basic cloud concepts.
    How to answer
    IaaS gives you infrastructure to manage (EC2); PaaS runs your code without managing servers (Elastic Beanstalk, App Service); SaaS is a finished application (Gmail).

  2. 2.Explain public and private subnets in a VPC.

    What they're checking
    Networking - the area most candidates are weakest in.
    How to answer
    A public subnet routes to an internet gateway; a private subnet doesn't, and reaches the internet out-only through a NAT gateway. Put load balancers in public subnets and app servers and databases in private ones.

  3. 3.Security group vs network ACL?

    What they're checking
    Security layers in AWS.
    How to answer
    Security groups are stateful and attach to instances, with allow rules only. NACLs are stateless, apply to subnets and support allow and deny rules.

  4. 4.How do IAM roles differ from IAM users?

    What they're checking
    Access management done right.
    How to answer
    Users are long-term identities with credentials; roles are assumed temporarily by services or people. Give EC2 or Lambda a role instead of storing access keys in code.

  5. 5.How would you make a web app highly available on AWS?

    What they're checking
    Architecture thinking.
    How to answer
    Instances in an auto scaling group across at least two availability zones behind a load balancer, a Multi-AZ database, static files on S3 with CloudFront, and health checks.

  6. 6.What S3 storage classes would you use for logs?

    What they're checking
    Cost awareness.
    How to answer
    Standard for recent logs, then a lifecycle rule to move them to Infrequent Access and later Glacier, and delete after the retention period.

  7. 7.When would you use Lambda instead of EC2?

    What they're checking
    Choosing the right compute.
    How to answer
    Lambda for event-driven, short or spiky workloads where you don't want to manage servers; EC2 for long-running processes, special software or steady heavy load where it's cheaper.

  8. 8.Your AWS bill doubled. What do you check?

    What they're checking
    Practical cost control.
    How to answer
    Cost Explorer by service and tag, then idle or oversized instances, unattached volumes, NAT gateway data, data transfer and forgotten test environments. Add budgets and alerts.

  9. 9.How do you secure an S3 bucket?

    What they're checking
    A common real-world breach cause.
    How to answer
    Block public access, use bucket policies with least privilege, encryption at rest, access logging, and pre-signed URLs for sharing files temporarily.

  10. 10.Describe a cloud setup you built or managed.

    What they're checking
    Hands-on experience.
    How to answer
    Draw it in words: networking, compute, database, storage, how it scales and how it's deployed. Mention one decision you'd change now.

Frequently asked questions

Is an AWS certification needed for cloud jobs?

It helps freshers get shortlisted - AWS Cloud Practitioner or Solutions Architect Associate are common starting points - but interviews still test hands-on understanding.

AWS or Azure for jobs in India?

Both are in demand. AWS leads overall; Azure is common at enterprises and in Microsoft-focused services teams.

What projects help for cloud interviews?

Deploy a small app with a load balancer, auto scaling, a managed database and infrastructure as code, and be ready to explain the networking.

Company interview guides for this role

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