Cloud Architecture Questions
Part of the DevOps Roadmap
In short
'Design a highly available setup for a food delivery app' has no single right answer. The interviewer is watching how you ask questions, make trade-offs and explain them.
'Design a highly available architecture for X application' — testing whether you can apply Phase 10's cloud fundamentals and Phase 13's HA/DR concepts to a concrete scenario.
Think of it like this
Planning the college fest ground
Before the fest, organisers ask how many people are coming, then place the stage, food stalls, entry gates and a backup generator. They plan crowd flow and what happens if it rains. A cloud design question is the same planning, with servers instead of tents.
Watch it happen
Structure for any design question
1/5Ask: how many users, which regions, what must never go down, any budget or compliance limits?
The big ideas
What you need to know
Ask before drawing
Jumping into boxes without requirements is the most common miss. Two minutes of questions shapes everything.
Zones and regions
Spread across availability zones for HA. Use another region mainly for disaster recovery or users far away.
Cache and queue
A cache absorbs repeated reads. A queue smooths spikes, so a lunch rush doesn't crush the order service.
Cost is a requirement
Mentioning cost, like reserved capacity or turning off idle environments, shows you think like an owner.
See it in code
Walk through the code
1Users -> DNS -> CDN (static files, images)2 |3 Load balancer (2 AZs)4 |5 App servers (autoscaling group, AZ-a + AZ-b)6 | | |7 Cache Database Queue -> Workers8 (Redis) (primary AZ-a, (order emails,9 standby AZ-b) rider assignment)10 11Backups -> object storage in a second region1/4The edge: DNS and a CDN for static content, then a load balancer spread across two zones.
A plain text sketch like this is fine in an interview. Talk through each box: why it's there and what happens if it fails.
Save yourself the pain
Common mistakes
Oops
Drawing a huge multi-region Kubernetes setup for an app with 500 users.
Do this instead
Match the design to the stated scale. Show you can start simple and explain how you'd grow it.
Oops
Never mentioning what happens when a component fails.
Do this instead
For each box, say how it fails and what takes over. That's what 'highly available' means.
Your mission
Design one on paper
Quick check
An interviewer says 'design a highly available API'. What should you do first?
Go deeper
- 1Practice a repeatable structure: requirements, compute, storage, networking, redundancy, cost.
- 2Prepare 1-2 fully worked-through examples (e.g. a 3-tier web app with auto-scaling).
- 3Practice justifying trade-offs (cost vs redundancy) explicitly as part of your answer.
More systems & infrastructure at this stop
Linux & Networking Questions
Kubernetes & Container Questions
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