A custom resource definition extends Kubernetes with a new resource type for application-specific business logic or constructs that built-in Kubernetes resources do not support. section 1.2.2
Use a custom resource definition when:
- Kubernetes lacks a resource model for a particular business requirement. section 1.2.2
- A Kubernetes-style API would provide a clearer operational interface for that requirement. section 1.2.2
A practical boundary
Stateless and stateful web applications generally do not need custom resource definitions; they become useful when deployment requires additional business logic or a new Kubernetes-style construct. section 1.2.2
