A web app needs zero-downtime deployments with the ability to warm up a new version and swap it into production instantly, keeping a rollback path. Which App Service feature does this?
A.Scale out rules
Autoscaling adds instances — doesn't deploy or roll back versions.
B.Deployment slots with swap
Slots + swap = the zero-downtime deployment mechanism. Correct.
C.Application Insights monitoring
Monitoring is observability, not deployment.
D.App Service Environment
ASE is a dedicated isolated hosting environment — unrelated to deployment mechanics.
Why this answer
Deployment slots (e.g., 'staging') host app versions alongside production — deploy to staging, warm it up, then 'swap' slot ↔ production instantly. Rollback = swap back. Requires Standard tier or above.
Correct answer: B · Last reviewed 2026-02-14
Official AWS references
Practice this interactively
Answer without seeing the solution first in the Compute Deployment practice session.
Practice Compute Deployment