Step 1 of 9 · Intro

Design an auto-scaling web app on AWS

Let capacity follow the load, and learn why reacting is not the same as being ready.

How it works

• ›Application Auto Scaling can scale an ECS service's task count by target tracking, step scaling, scheduled scaling or predictive scaling.
• ›Target tracking and step scaling react to a CloudWatch metric, so capacity arrives after the load does. Scheduled and predictive scaling can add capacity ahead of time.
• ›Every scaling policy has a maximum you set. Beyond it, you need another way to cut load, such as caching.
• ›Limits come from AWS documentation (default quotas in us-east-1). Where AWS publishes no figure, such as how many requests a container or database handles, the lab states its assumption on the component.

What you'll build

1. A fixed-size stack at 1,500 requests a second
2. An auto-scaled service for 5,000
3. An edge cache for a spike that outgrows the task maximum
4. A scaling plan for a predictable daily spike
5. A good scaling metric
6. Why scale-in is slow
7. Slow start
8. Paying for what you use at night