Consuming Services

This document describes how to use (consume) Services offered in KDP.

Background

A “service” in KDP defines a unique Kubernetes API Group and offers a number of resources (types) to use. A service could offer certificate management, databases, cloud infrastructure or any other set of Kubernetes resources.

Services are provided by service owners, who run their own Kubernetes clusters and take care of the maintenance and scaling tasks for the workload provisioned by all users of the service(s) they offer.

A KDP Service should not be confused with a Kubernetes Service. Internally, a KDP Service is ultimately translated into a kcp APIExport with a number of APIResourceSchemas (~ CRDs).

Browsing Services

Log in to the KDP Dashboard and choose your organization. Then on “Services” page, select “External Services” tab to see a list of all external services added into this organization. Click “Add Services” button to see a list all services that you have access to. For each service that is active and hasn’t been added to the organization yet, a button is offered to add it to the organization.

Note that every Service shows:

• its main title (the human-readable name of a Service, like “Certificate Management”)
• its internal name (ultimately the name of the Kubernetes Service object you would need to manually enable the service using kubectl)
• a short description

Check out Your First Service if you want to publish services by yourself.

Enabling a Service

After clicking on “Add to Organization” in the service catalog, the following wizard will open to confirm adding a service:

Several options are offered when adding a service:

• “Create default roles for resources managed by this service” will optionally create a standard set of RBAC roles within the workspace that allow giving different levels of access to this specific service. This is not mandatory, but otherwise roles may need to be created separately.
• The “Resources” section informs you about resources that the service is requesting access to (claiming) to function properly, e.g. to be able to read or write secret data associated with objects of that service. Service owners are encouraged to gracefully handle situations in which resource access is not granted, but service quality and functionality will likely suffer. You can grant/revoke access to resources for a service at any time.

Manually

Alternatively, create the APIBinding object yourself. This section assumes that you are familiar with kcp on the Command Line and have the kcp kubectl plugin installed.

First you need to get the kubeconfig for accessing your kcp workspaces. Once you have set your kubeconfig up, make sure you’re in the correct namespace by using kubectl ws <path to your workspace>. Use kubectl ws . if you’re unsure where you’re at.

To enable a Service, use kcp bind apiexport and specify the path to and name of the APIExport.

# kubectl kcp bind apiexport <path to KDP Service>:<API Group of the Service>
kubectl kcp bind apiexport root:my-org:my.fancy.api

Without the plugin, you can create an APIBinding manually, simply kubectl apply this:

apiVersion: apis.kcp.io/v1alpha1
kind: APIBinding
metadata:
  name: my.fancy.api
spec:
  reference:
    export:
      name: my.fancy.api
      path: root:my-org

Shortly after, the new API will be available in the workspace. Check via kubectl api-resources. You can now create objects for types in that API group to your liking and they will be synced and processed behind the scenes.

Note that a Service often has related resources, often Secrets and ConfigMaps. You must explicitly allow the Service to access these in your workspace and this means editing/patching the APIBinding object (the kcp kubectl plugin currently has no support for managing permission claims). For each of the claimed resources, you have to accept or reject them:

spec:
  permissionClaims:
    # Nearly all Services in KDP require access to namespaces, rejecting this will
    # most likely break the Service, even more than rejecting any other claim.
    - all: true
      resources: namespaces
      state: Accepted
    - all: true
      resources: secrets
      state: Accepted # or Rejected

Rejecting a claim will severely impact a Service, if not even break it. Consult with the Service’s documentation or the service owner if rejecting a claim is supported.

When you change into (kubctl ws …) a different workspace, kubectl will inform you if there are outstanding permission claims that you need to accept or reject.