Compose stacks with kro

In the ACK lab you applied three separate manifests (a Table resource, a ConfigMap override, and a Pod Identity association) to migrate carts onto an AWS-managed DynamoDB table. That's the right altitude for a one-off, but a platform team running this for many services would want one user-facing resource that captures the whole stack.

In this lab you'll do exactly that with kro (Kube Resource Orchestrator), delivered as an EKS capability. kro lets a platform team package many Kubernetes resources behind one simple, custom resource. There are two pieces:

• A ResourceGraphDefinition (RGD) is the blueprint. It defines a new custom resource type (here, CartsStack), the handful of inputs it accepts (like a table name), and the graph of underlying resources one instance expands into: a Namespace, an ACK Table, a ConfigMap, a ServiceAccount, a Deployment, and a Service. A platform team writes this once.
• An instance is what everyone else applies: a short CartsStack resource with just the inputs filled in. kro reads it and creates the whole graph for you, in the right order.

Like the other capabilities, kro's controllers run in AWS-owned infrastructure outside the cluster with AWS handling their operations. Inside the cluster you only see the Custom Resource Definitions (CRDs) it registers, starting with resourcegraphdefinitions.kro.run.

What's been set up for you

• The kro EKS-managed capability is ACTIVE on the cluster, with the resourcegraphdefinitions.kro.run CRD registered.
• The ACK DynamoDB capability from the ACK lab is still ACTIVE, so kro will compose its Table resource alongside native Kubernetes objects.
• The pre-provisioned ${EKS_CLUSTER_AUTO_NAME}-carts-dynamo IAM role is wildcard-scoped to ${EKS_CLUSTER_AUTO_NAME}-carts-* tables, so the same role covers the ACK lab's -carts-fastpath table and the kro lab's -carts-kro table without changes.

Throughout this lab, we will:

1. Verify the kro capability is ACTIVE and the resourcegraphdefinitions.kro.run CRD is present.
2. Apply a CartsStack ResourceGraphDefinition that composes Namespace + ACK Table + ConfigMap + ServiceAccount + Deployment + Service.
3. Apply a CartsStack instance, observe kro reconcile its child resources in order, then bind a Pod Identity association so the carts Pod can read and write the new table.

A single CartsStack apply produces this graph:

                you apply:
                CartsStack/carts-kro          (one CR, two required fields)
                       │
                       ▼  kro reconciler expands the RGD
                       │
   ┌──────────┬────────┴──┬──────────┬─────────────┬──────────┐
   ▼          ▼           ▼          ▼             ▼          ▼
Namespace   Table     ConfigMap     SA        Deployment    Service
                        │                          │
                        ▼                          ▼
                   ACK DynamoDB                 Pod (carts-…)
                    controller                       │
                        │                            │ + aws eks create-pod-identity-association
                        ▼                            ▼
                AWS DynamoDB table          AWS_CONTAINER_CREDENTIALS
                (eks-workshop-…-carts-kro)   via Pod Identity Agent

備考

kro only reconciles Kubernetes resources; it never calls AWS APIs itself. The AWS DynamoDB table in the graph above is created by the ACK controller from the ACK lab, which kro drives by creating the Table resource.

Verify the capability

Confirm the capability is ACTIVE:

~$aws eks describe-capability \

--cluster-name $EKS_CLUSTER_AUTO_NAME \

--capability-name $EKS_CAP_KRO_CAPABILITY \

--query 'capability.status' --output text

ACTIVE

Now look at the CRD kro registered, which is the RGD "blueprint" type from above:

~$kubectl api-resources --api-group=kro.run

NAME                       SHORTNAMES   APIVERSION         NAMESPACED   KIND

resourcegraphdefinitions   rgd          kro.run/v1alpha1   false        ResourceGraphDefinition

Note NAMESPACED: false: an RGD is cluster-scoped, because the blueprint is shared across the whole cluster. The instances you create from it (your CartsStack resources) are namespaced, since each one owns resources in a specific namespace. With the capability ACTIVE and the RGD CRD in place, we're ready to define our first RGD.