City permit API instances are upgraded a few at a time so the service never goes fully dark. Which deployment strategy is being used?
Select an answer to reveal the explanation.
Short Explanation
Rolling is like repainting a bridge one section at a time while cars still cross the other lanes. A few instances upgrade; the rest keep answering permits. The service stays up — that gradual subset swap is rolling, not parking a whole second bridge (blue-green) or shutting the road.
Full Explanation
Rolling deployments replace or upgrade instances in batches so capacity remains available throughout the change. Gradual subset updates with continuous service availability are the hallmark of rolling strategy. Blue-green depends on a parallel full environment and a traffic switch; canary focuses on limited user exposure for validation; full outage windows describe planned downtime in-place work, not rolling.