A team must roll out updates on the production instance of an application. To avoid any service down time, the new version must be released alongside the old version. After the team ensures that the n

Rolling deployment gradually replaces instances of the old version with instances of the new version, which can cause temporary inconsistencies or brief downtime during updates.

Blue/green deployment involves having two identical production environments, 'blue' (current version) and 'green' (new version). Traffic is routed to the blue environment, while the green environment is deployed and tested; once validated, traffic is switched to the green environment, and the blue environment is eventually decommissioned, ensuring no downtime. This matches the described process of running new and old versions concurrently, redirecting traffic, and then shutting down the old.

Shadow deployment sends a copy of live traffic to a new version to test its performance without impacting real users, but the new version does not actively serve live traffic initially.

Canary deployment routes a small percentage of live traffic to the new version to test it with a limited user base before a full rollout, rather than running fully parallel environments.