Problems / LLM serving, medium

GPU autoscaling ceiling

The GPU pool autoscales from 2 to 3 nodes of 16 slots each, but traffic needs more than 3 nodes.

Free to open. Runs in your browser, no sign-up.

Your goals

Success ≥ 99%, p99 ≤ 5 s.

The traffic

70 requests a second for 30 seconds: 100% request (reads).

The system

What each component does in this design, and what calls it. The simulator mimics each one from these settings.

ComponentIts job hereSettings
Load balancerLoad balancerTraffic enters here.Calls AI app.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header.–
AI appApp serviceLoad balancer forwards to it.Calls GPU serving pool.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s.3 replicas × 500 slots · timeout 30 s
GPU serving poolSelf-hosted serving poolAI app calls it.GPU servers batch requests together; throughput rises with batch size until memory runs out.16 slots · 2–3 instances

Hints

Try it first. Open one hint at a time if you get stuck.

Hint 1

Look at Instances on the GPU pool.

Hint 2

Autoscaling stops at its maximum.

One way to solve it

Raise the maximum (and minimum) number of GPU nodes.

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