Part II — Composing Applications

The app layer deploys heterogeneous systems as one unit and exposes typed handles to workloads.

Use this entry pattern when the system under test is not a single uniform cluster. A root AppDeployment deploys children such as processes, uniform child clusters, and in-process services. It exposes their handles, while the scenario runtime schedules test behavior and cleanup.

• AppHost and with_app — hosting a composed app inside a scenario
• AppDeployment and DeployContext — the deployment contract and its context
• Handle Ownership and Teardown — typed access, managed lifetime, and reverse cleanup
• One Binary: LocalProcessApp — the smallest building block
• Uniform Child Clusters: LocalAppCluster — a managed cluster as one component
• Composing Heterogeneous Stacks — the root-app pattern, end to end
• Backend Scope — what the app layer supports today