Incident · Sev 1

Black Friday outage

Checkout went down two minutes into the Black Friday sale, and requests aren't reaching the database. Work from the shoppers inward: open the failing component, read its logs, and pick the fix. Each right answer turns that hop green.

Requests succeeding0%

XP earned 0

Select the pulsing load balancer to investigate.

Logs

Open the failing component to read its logs.

Start investigating

Open the load balancer, read its logs, and choose the fix.

What this incident covers

Load balancer (spreads traffic): Load Balancing Intro
App servers (app-1, app-2): Backpressure & Flow Control
Cache (Redis): Caching Basics
Database (Postgres): Failures, Retries & Rate Limits