You have a microservice on Azure Container Apps with external HTTP ingress. Updates to the service must not cause downtime. Which deployment configuration should you use to update the service?

Enabling single revision mode for Azure Container Apps allows for zero-downtime updates. When a new revision is deployed in single revision mode, the old revision continues to serve traffic until the new revision is healthy and ready. Once the new revision is healthy, traffic is seamlessly switched to it, and the old revision is terminated. This ensures continuous availability of the service. Multiple revision mode is used for A/B testing or blue/green deployments, where you might want to split traffic between revisions or manually promote a new revision, which could introduce downtime if not managed carefully. Using multiple environments or a single environment for all containers does not directly address zero-downtime updates for a single service. A private container registry and a single image are best practices for image management but don't inherently provide zero-downtime deployment capabilities.