Kubernetes Resource Orchestrator (KRO)

KRO (Kube Resource Orchestrator) is a Kubernetes-native controller under kubernetes-sigs. It turns a ResourceGraphDefinition into a custom API and a reconciled bundle of cluster objects. You declare a graph of resources and how they relate. kro generates the CRD and controllers that keep the bundle in sync. We assess it for platform teams that want reusable abstractions without hand-rolling a Go operator for every bundle. It fits alongside Helm and Kustomize when the goal is a new API surface, not manifest templating alone.

Blurb

Kube Resource Orchestrator (kro) is a Kubernetes-native controller that simplifies the creation and management of complex custom resources for Kubernetes.

Summary

What it does: A ResourceGraphDefinition (RGD) describes multiple Kubernetes resources, dependencies between them, and a SimpleSchema for the instance API. kro validates the RGD, materializes a CRD, and runs dedicated controllers to reconcile instances. Wiring uses CEL expressions, validated at creation time.

When to use: platform teams publishing internal building blocks (app + IAM + networking); compositions that mix core resources with third-party CRDs; EKS shops that want managed kro via EKS Capabilities.

When to skip: a single Deployment/Service pair (Kustomize overlays are enough); packaged third-party charts (Helm); complex admission or multi-step imperative logic (a full operator or Shell Operator hooks may fit better).

Ecosystem notes: kro lives in kubernetes-sigs/kro and is a SIG Cloud Provider subproject. AWS, Azure, and Google Cloud collaborate on it. EKS documents kro for composing ACK-managed AWS resources into higher-level APIs.

Details

Core CRDs: ResourceGraphDefinition defines the graph; instances of the generated CRD create the underlying objects.

Install: Helm chart or raw manifests from the kro release artifacts; on EKS, optional EKS Capability for a managed controller.

Docs: kro.run, kubernetes-sigs/kro, EKS kro guide.