You need to deploy two tightly coupled containers to Azure Container Instances: an API container and a sidecar that reads/writes shared data. The containers must share a lifecycle, have a single public IP/port, communicate over localhost, and share a persistent volume. What should you do?

The correct solution is to deploy both containers into a single Azure Container Instances (ACI) container group. A container group in ACI is designed for tightly coupled containers that share a lifecycle, resources (like CPU and memory), a network, and can mount shared volumes. This allows them to communicate over localhost and present a single public IP address. Defining a shared Azure Files volume within the group ensures persistent data sharing between the API and sidecar containers. Incorrect options: Deploying each container as its own ACI instance would mean separate lifecycles, separate IPs (unless fronted by a load balancer), and communication wouldn't be over localhost. Azure App Service for Containers is not designed for tightly coupled sidecar patterns with localhost communication and shared lifecycles in the same way ACI container groups are. Azure Kubernetes Service (AKS) could host these containers, but using separate Deployments and a LoadBalancer Service would not achieve the localhost communication or the shared lifecycle of a single ACI container group. While AKS offers more advanced orchestration, ACI container groups are simpler and more direct for this specific tightly coupled scenario.