Which deployment approach minimizes downtime and risk when rolling out application updates?

The deployment approach that minimizes downtime and risk when rolling out application updates is blue/green deployment. This method involves maintaining two identical environments: one live (the blue environment) and one idle (the green environment). When an application update is ready, it is deployed to the idle environment (green). Once testing is complete and the new version is confirmed to be stable, traffic is switched over from the blue environment to the green environment.

This approach effectively reduces downtime because users are immediately directed to the live instance of the application, while the update is thoroughly tested beforehand. If any issues arise, it is straightforward to revert to the blue environment, thus minimizing risk. Additionally, blue/green deployment allows for continuous delivery and rapid rollback, making it a robust choice for maintaining high availability while implementing updates.

In contrast, rolling deployment gradually replaces instances of the application with the new version, which can lead to temporary inconsistencies during the rollout process and may involve more downtime. Canary deployments introduce new software to a small subset of users first, but can involve continuous back-and-forth adjustments if problems arise. The recreate deployment approach invloves shutting down instances of the old version before bringing up the new version, leading to unavoidable downtime.