Cluster API Source

[jplitza]

Cluster API is a framework for creating new Kubernetes clusters from an existing management Kubernetes cluster and representing their components with custom resources in said management cluster (Cluster, ControlPlane, Machine, ...)

To make the high availability control plane of such a cluster usable under a central name, one can use DNS names with multiple A/AAAA records.

It would be great to use ExternalDNS to manage these records!

A Cluster contains the following:

apiVersion: cluster.x-k8s.io/v1beta1
kind: Cluster
metadata:
  name: test-cluster
spec:
  controlPlaneEndpoint:
    host: test-cluster.k8s.example.org

The Machine resources for the associated control plane contain:

apiVersion: cluster.x-k8s.io/v1beta1
kind: Machine
metadata:
  labels:
    cluster.x-k8s.io/cluster-name: test-cluster  # Links the machine to the Cluster and hence the domain name
    cluster.x-k8s.io/control-plane: ""  # Indicates it is a control plane machine, not a worker machine
status:
  phase: Running  # Probably shouldn't add non-running Machines
  addresses:
  - address: 2001:db8::1  # Should cause a AAAA record to be added
    type: ExternalIP
  - address: fd00::1  # Should only be added when there is no ExternalIP
    type: InternalIP

Sources cannot be implemented out-of-tree, right? Would this be too nieche of a source to be merged?

The alternative would probably be some controller that converts those ClusterAPI resources to ExternalDNS Endpoint resources.

[k0da]

@jplitza Hi, we've created this exactly for that use case.

[jplitza]

Nice, thanks for the hint!