Catalogs

Catalog Entries

In order to manage Custom Resources from a ServiceCluster we have to tell KubeCarrier how to find them and how we want to offer them to our users.

First we need some kind of CustomResourceDefinition or Operator installation in our ServiceCluster. To help get you started we have a fictional example CRD that can be used without having to setup an Operator.

Register the CRD in the ServiceCluster.

# make sure you are connected to the ServiceCluster
# that's `eu-west-1` if you followed our earlier guide.
$ kubectl config use-context kind-eu-west-1
Switched to context "kind-eu-west-1".

$ kubectl apply \
  -f https://raw.githubusercontent.com/kubermatic/kubecarrier/v0.3.0/docs/manifests/couchdb.crd.yaml
customresourcedefinition.apiextensions.k8s.io/couchdbs.couchdb.io created

$ kubectl get crd
NAME                  CREATED AT
couchdbs.couchdb.io   2020-03-10T10:27:51Z

Now we will tell the KubeCarrier installation to work with this CRD. We can accomplish this, by creating a CatalogEntrySet. This object describes which CRD should be fetched from which ServiceCluster, metadata for the Service Hub and it will limit which fields are available to users.

CatalogEntrySet definition

apiVersion: catalog.kubecarrier.io/v1alpha1
kind: CatalogEntrySet
metadata:
  name: couchdbs.eu-west-1
spec:
  metadata:
    displayName: CouchDB
    description: The compfy database
  discover:
    crd:
      name: couchdbs.couchdb.io
    serviceClusterSelector: {}
  derive:
    expose:
    - versions:
      - v1alpha1
      fields:
      - jsonPath: .spec.username
      - jsonPath: .spec.password
      - jsonPath: .status.phase
      - jsonPath: .status.fauxtonAddress
      - jsonPath: .status.address
      - jsonPath: .status.observedGeneration
# make sure you are connected to the KubeCarrier Cluster
# that's `kubecarrier` if you followed our earlier guide.
$ kubectl config use-context kind-kubecarrier
Switched to context "kind-kubecarrier".

$ kubectl apply -n team-a \
  -f https://raw.githubusercontent.com/kubermatic/kubecarrier/v0.3.0/docs/manifests/catalogentryset.yaml
catalogentryset.catalog.kubecarrier.io/couchdbs created

$ kubectl get catalogentryset -n team-a
NAME       STATUS   CRD                   AGE
couchdbs   Ready    couchdbs.couchdb.io   19s

As soon as the CatalogEntrySet is ready, you will notice two new CustomResourceDefinitions appearing in the Cluster:

$ kubectl get crd -l kubecarrier.io/origin-namespace=team-a
NAME                                CREATED AT
couchdbs.eu-west-1.team-a           2020-07-31T09:36:04Z
couchdbs.internal.eu-west-1.team-a  2020-07-31T09:35:50Z

The couchdbs.internal.eu-west-1.team-a object is just a copy of the CRD present in the ServiceCluster, while couchdbs.eu-west-1.team-a is a “slimed-down” version, only containing fields specified in the CatalogEntrySet. Both CRDs are “namespaced” by their API group.

Catalogs

Now that we have successfully registered a CustomResourceDefinition from another cluster, attached metadata to it and created a “public” interface for other people, we can go ahead and actually offer this CouchDB object to other users.

The CatalogEntrySet we created in previous step is managing CatalogEntries for all ServiceClusters that match the given serviceClusterSelector.

$ kubectl get catalogentry -n team-a
NAME                 STATUS   BASE CRD                            TENANT CRD                  AGE
couchdbs.eu-west-1   Ready    couchdbs.internal.eu-west-1.team-a  couchdbs.eu-west-1.team-a   26s

We can now reference these CatalogEntries in a Catalog and offer them to Tenants. Every Account with the Tenant role has a Tenant object created in each Provider namespace.

$ kubectl get tenant -n team-a
NAME     AGE
team-b   5m35s

These objects allow the Provider to organize them by setting labels on them, so they can be selected by a Catalog. This Catalog selects all CatalogEntries and offers them to all Tenants:

Catalog definition

apiVersion: catalog.kubecarrier.io/v1alpha1
kind: Catalog
metadata:
  name: default
spec:
  # selects all the Tenants
  tenantSelector: {}
  # selects all the CatalogEntries
  catalogEntrySelector: {}
$ kubectl apply -n team-a \
  -f https://raw.githubusercontent.com/kubermatic/kubecarrier/v0.3.0/docs/manifests/catalog.yaml
catalog.catalog.kubecarrier.io/default created

$ kubectl get catalog -n team-a
NAME      STATUS   AGE
default   Ready    5s

When the Catalog is ready, selected Tenants can discover objects available to them and RBAC is setup to users to work with the CRD in their namespace. Here we also use kubectl user impersonation (--as), to showcase RBAC:

# Offering objects contain information about CRDs that are shared to a Tenant.
# They contain all the information to validate and create new instances.
$ kubectl get offering -n team-b --as=team-b-member
NAME                        DISPLAY NAME   PROVIDER   AGE
couchdbs.eu-west-1.team-a   CouchDB        team-a     3m15s

# Region exposes information about the underlying Clusters.
$ kubectl get region -n team-b --as=team-b-member
NAME               PROVIDER   DISPLAY NAME   AGE
eu-west-1.team-a   team-a     EU West 1      5m14s

# Provider exposes information about the Provider of an Offering.
$ kubectl get provider -n team-b --as=team-b-member
NAME     DISPLAY NAME   AGE
team-a   The A Team     6m11s