Exam AWS Certified Developer - Associate DVA-C02 topic 1 question 509 discussion

B is the correct answer. D is wrong because though it's useful for testing new features on a limited scale, it does not minimize the overall deployment duration and availability as effectively as immutable deployments.

A canary deployment is a strategy where a new version of an application is deployed to a small subset of instances first. Once it has been validated as stable, it is gradually rolled out to the remaining instances. This approach provides the following benefits: Minimal performance impact: Issues with the new version can be identified early before it affects all users. Maximum availability: Problems can be quickly rolled back, minimizing downtime or service interruptions. Fast delivery of features: By deploying incrementally, new features reach all users promptly after initial validation.

Immutable deployment creates a new set of instances with the updated version of the application. Once the new instances are verified as healthy, they replace the old instances. This strategy ensures high availability and minimizes the risk of performance impact since the old instances remain untouched until the new instances are validated.