Design VPC, IP plan, management, storage, SSO
Company: Amazon
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Technical Screen
Design and deploy a multi-layer VPC architecture: how would you segment networks (public, private, management), route between layers, and enforce security with subnets, route tables, and security groups? For a fleet of 2,000 servers, plan the CIDR allocations and estimate how many IPs are required, accounting for per-subnet reserved addresses and future growth. Propose a centralized way to manage both Linux and Windows instances (e.g., configuration management, patching, access control, inventory). Recommend a shared storage solution for concurrent access by multiple servers (e.g., NFS/EFS, SMB/FSx, or alternatives) and compare performance, consistency, and cost trade-offs. Finally, design single sign-on so users authenticate once to access multiple services, including the identity provider choice, trust relationships, and token flows.
Quick Answer: This question evaluates competency in cloud network and platform architecture, covering VPC/subnet design and routing, CIDR/IP planning for large fleets, centralized Linux/Windows fleet management, shared concurrent storage considerations, and federated SSO and identity flows.