Aws Interview Q&A

Q: When would you choose this platform?

Choose based on: existing vendor relationships, team expertise, compliance requirements, pricing for your specific workload mix, and regional availability.

Q: What are the core shared services across clouds?

Compute (EC2/VM/GCE), Object Storage (S3/Blob/GCS), Managed K8s (EKS/AKS/GKE), IAM (IAM/AAD/IAM), Serverless (Lambda/Functions/Cloud Functions), Database (RDS/Azure SQL/Cloud SQL).

Q: How do you manage costs in this cloud?

Use reserved/committed use for baseline workloads (40-60% savings). Spot/preemptible for batch/fault-tolerant. Right-size instances (use monitoring data). Storage tiering. Auto-scaling to match actual demand.

Quick Reference — Aws

Key Points for Revision

•Review the overview section for core architecture and fundamentals

•Practice commands/configurations from the cheatsheet section

•Use interview Q&A for active recall before exams or interviews

•Cross-reference with related tools in the cloud academy

Practice Approach

1.Read the overview to understand what and why

2.Work through fundamentals for how

3.Attempt hands-on labs or configurations

4.Test yourself with interview questions

5.Keep cheatsheet accessible for quick reference during work

Further Learning

Connect this topic to the broader cloud ecosystem.

Each tool in this academy is designed to work with others —

understanding the integration points is what separates intermediate from senior practitioners.

AWS Interview Q&A

Q: What is the difference between security groups and NACLs?

Security Groups: stateful (return traffic automatically allowed), attached to instances/ENIs, allow rules only. NACLs: stateless (must explicitly allow inbound AND outbound), attached to subnets, allow and deny rules, evaluated in order. Use SGs for instance-level control, NACLs for subnet-level defense in depth.

Q: Explain VPC peering vs Transit Gateway.

VPC Peering: direct 1:1 connection between two VPCs (same or different accounts/regions). Non-transitive — if A peers with B and B peers with C, A cannot reach C through B. Transit Gateway: hub-and-spoke model, centrally routes traffic between many VPCs and on-premises. More scalable; supports transitive routing.

Q: What is the difference between EBS, EFS, and S3?

EBS: block storage, attached to single EC2 instance, persistent, low latency. EFS: network file system (NFS), shared across multiple EC2 instances, scales automatically. S3: object storage, virtually unlimited scale, accessed via API (not mountable as filesystem natively), cheapest per GB.

Q: How does IAM Roles differ from IAM Users?

Users: long-term credentials for humans or applications (access key + secret). Roles: temporary credentials, assumed by AWS services (EC2, Lambda), federated users (SSO), or cross-account access. Best practice: no long-term access keys for applications — use roles. EC2 instance profiles attach a role to the instance.

Q: What is AWS Lambda and its cold start issue?

Serverless compute — runs code without provisioning servers. Cold start: first invocation (or after idle period) requires initialising the execution environment (download code, start runtime). Adds 100ms-1s latency. Mitigations: Provisioned Concurrency (pre-warm containers), SnapStart (Java), keep functions warm via scheduled pings.

This section is part of the SynfraCore learning platform. Use the sidebar to navigate to Overview, Fundamentals, Advanced, and Cheatsheet sections for comprehensive coverage of this topic.

AWS Core Services Overview — Interview Q&A