Global Checkout Brownout

No service behind checkout is fully down. Pricing, Promotions, and Tax have each begun returning moderately elevated latency and error rates at the same time — individually, none of the three looks like an outage on its own health dashboard. Because all three sit on the same synchronous checkout critical path, their latencies add together rather than hide behind each other, and end-to-end checkout latency has become unusable even though nothing reads as 'down.' Business invariants: payment authorization and inventory reservation must remain correct at all times and can never be traded away to relieve latency elsewhere, however severe the brownout gets. Promotions may be disabled outright for the duration of the incident. Tax may use the business-authorized bounded fallback rate table instead of a live calculation. Pricing may serve a short-TTL cached price instead of calling live. Checkout may return reduced enrichment, or a visibly partial/reduced-functionality result, rather than fail end-to-end.

Difficulty

Principal

Expected Time

~20 min

Category

Distributed Systems