What are Kubernetes Custom Resource Definitions (CRDs)?

Custom Resource Definitions (CRDs) in Kubernetes allow users to extend the base API with custom objects and enable management of other parts of infrastructure such as network devices. Commonly, CRDs are included with tool installations on a cluster. Creating a CRD involves defining a resource definition using YAML files. Once created, these custom objects can be managed by Kubernetes and used to create automation scripts through CustomController objects. Spacelift is an alternative CI/CD automation tool that helps manage complexities and compliance challenges of using Kubernetes.