Explore the evolution and potential of Custom Resource Definitions (CRDs) in Kubernetes during this keynote presentation from KubeCon + CloudNativeCon. Discover how CRDs have transformed from primarily out-of-tree, third-party extensions to becoming integral components for managing in-tree, first-party Kubernetes resources. Learn about the ongoing efforts to refine and enhance Kubernetes as a modular and extensible platform by factoring out non-essential elements from its core. Gain insights into building CRDs as first-class citizens in Kubernetes based on first-hand experiences, and understand how they can be seamlessly integrated with other core API objects. Get introduced to Kubebuilder, a Software Development Kit (SDK) for building and publishing Kubernetes APIs, and learn how it simplifies the process of writing custom controllers for CRDs. Follow the journey of CRDs' growth, explore practical examples, and discover the vision for their future in Kubernetes ecosystem.