Which design type is this question?

It is a cloud infrastructure question. You design an auto-scaling system for web servers and explain your choices the way you would in an interview.

Is this question asked at entry level?

It is marked Easy, so it suits engineers who are new to cloud infrastructure interviews. It is also a good warm-up before harder questions.

What should I cover first?

Start with the workloads, the availability target and the security and cost limits. Agree on scope with the interviewer before you design anything.

Can I practise it for free?

It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.

Design an auto-scaling system for web servers

PremiumCloud infrastructureEasy

Auto scaling
Target tracking
Load balancer

Quick answer

This cloud infrastructure interview question asks you to design an auto-scaling system for web servers. Aim for a design that runs reliably and securely in the cloud at a sensible cost, then explain the services, regions, deployment and trade-offs. Interviewers want to see how you balance reliability, security and cost.

The problem

Design an auto-scaling system for web servers, like the auto-scaling groups cloud providers offer: it watches load and adds or removes servers behind a load balancer. The hard parts are reacting fast to spikes, not flapping up and down, and never removing a server that is still serving users.

What must an auto-scaling system for web servers do?

Scaling policy: Keep average CPU near a 50% target across the group, within a minimum and maximum server count.
Launch and register: Start servers from a versioned image, wait until the app passes its health check, then register it with the load balancer.

5 more requirementsUnlock to see all

How well must it do it?

Fast reaction: Decide to scale out within 1 minute of a load rise, and have the new servers serving about 2.5 minutes after that decision.
Stability: No flapping: scale in slowly, only after load stays low for 15 minutes.

3 more requirementsUnlock to see all

What scale should you design for?

Use these numbers in your estimates.

The scale numbers unlock with this questionUnlock

Key concepts

Auto scaling
Target tracking
Load balancer
Health checks
Instance warm up
Connection draining

How you’ll practise

6 short steps · save and come back any time

Requirements
Environments and topology
Deployment pipeline
Reliability and disaster recovery
Observability and cost
Wrap-up

Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.

What do interviewers look for?

In any cloud infrastructure design round.

Clarifies availability, security and cost targets
Chooses managed services with reasons
Plans regions, zones and failover
Covers identity, secrets and network boundaries
Explains deployment, rollback and observability
Keeps an eye on cost as usage grows

Questions people ask about this interview question

Which design type is this question?: It is a cloud infrastructure question. You design an auto-scaling system for web servers and explain your choices the way you would in an interview.
Is this question asked at entry level?: It is marked Easy, so it suits engineers who are new to cloud infrastructure interviews. It is also a good warm-up before harder questions.
What should I cover first?: Start with the workloads, the availability target and the security and cost limits. Agree on scope with the interviewer before you design anything.
Can I practise it for free?: It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.

The problem

What must an auto-scaling system for web servers do?

How well must it do it?

What scale should you design for?

Key concepts

How you’ll practise

What do interviewers look for?

Questions people ask about this interview question

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