Requirement

The cloud-based web application must scale out automatically fast enough to absorb a sharp traffic increase without manual intervention and without disproportionate cost growth.

Acceptance Criteria

• Scale-out completion: when sustained incoming traffic rises to 150% of the established baseline for 5 min, the platform adds enough healthy serving capacity within <= 2 min after threshold breach; source: load-test report plus autoscaling and health-check events; horizon: each quarterly elasticity test.
• Post-scale stability: during the first 10 min after scale-out, request latency stays at p95 <= 3 s and average CPU utilization of serving instances stays at <= 70% under a traffic level of 200% of baseline; source: APM dashboard and infrastructure metrics; horizon: each quarterly elasticity test.
• Cost bound and gate: under the same 200% traffic test, hourly compute cost rises by <= 150% over the baseline hour; if any threshold is missed, rollout of the changed autoscaling configuration is blocked within <= 1 business day; source: cost report and release gate log; horizon: each quarterly elasticity test.