Argo CD App of Apps pattern

WHAT THIS TESTS Whether you understand that Argo CD Applications are themselves Kubernetes resources, and how to exploit that to manage fleets of apps declaratively.

A GOOD ANSWER COVERS An Argo CD Application is a custom resource describing a source repo, a path, and a destination. The App of Apps pattern defines a single root Application whose Git path does not contain raw workloads but rather more Application manifests. When the root syncs, it creates those child Applications, and each child then syncs its own real workloads. This gives you a tree: one parent governing many children. It is powerful because you can bootstrap an entire cluster with one command by pointing Argo CD at the root app; adding a new application becomes a single commit adding a child Application manifest; and you can group and order things by environment or team. It centralizes management and makes the full set of deployed apps itself declarative and version-controlled. Note the related ApplicationSet, which generates Applications from generators like lists, clusters, or Git directories, and is often preferred for templated fan-out.

COMMON WRONG ANSWERS Confusing App of Apps with ApplicationSet, thinking the root app deploys workloads directly rather than child Applications, or missing why it helps bootstrapping and onboarding.

LIKELY FOLLOW-UPS How does App of Apps differ from ApplicationSet? How do sync waves order child apps? How do you handle cascading deletion?

ONE CONCRETE EXAMPLE You create a root Application pointing at apps/ in Git. That directory holds five Application manifests: monitoring, ingress, database, and two services. Syncing the root creates all five child Applications, each of which then deploys its workloads. To add a sixth service later, you commit one new Application manifest into apps/, and the next sync brings it online automatically.