A DevOps team is managing a critical application. They need to ensure that every deployment to production is fully reversible to minimize downtime in case of critical issues. The deployment process should allow for an immediate switch back to the previous stable version if problems are detected. Which deployment strategy is most suitable for achieving this goal?

Why the other options are wrong

• A. Immutable deployment ensures that deployed artifacts are never changed in place; new deployments involve creating new instances. While good for consistency, it doesn't inherently guarantee immediate full rollback via a traffic switch like Blue/Green does; a rollback would typically involve deploying the previous immutable version, which is a new deployment process.
• B. Rolling deployment gradually replaces instances of the old version with the new. While it offers some rollback capability by reversing the roll, it's not an immediate, full-environment switch and can still incur downtime or partial service disruption during the rollback process.
• D. Canary release deploys to a small subset of users first. While it minimizes impact, it's primarily for testing new features in production, not for ensuring immediate full rollback of an entire deployment.