Document ClusterProvider API & Contract

[In-Ko]

Description

For the new MCP system as well as for its new setup, we need an improved way of ordering k8s clusters. According to the planned architecture, this is meant to happen via Cluster k8s resources which are interpreted by different ClusterProviders, depending on their class/type/flavor.

We have to design a first version (we will likely have to improve it while implementing) for the Cluster resource and the contract how the cluster provider controllers are expected to interact with this resource.

Ideally, we would already create a 'ClusterProvider Implementation Template' repository that can be cloned and adapted when creating a new ClusterProvider. We want this for the open-source community anyway and it would also help with our own ClusterProvider implementations.

Tasks

• Document contract
  • How does a ClusterProvider behave?
  • Which fields in the Cluster resource is it allowed to modify, which is it expected to modify?
• Create Cluster API
  • Probably in a new 'openMCP API' repo?
• (to be done later, and move to another individual task) Stretch: Prepare 'ClusterProvider Implementation Template' repository
  • Idea: For implementing a new ClusterProvider, just clone the template and adapt everything that says TODO.

[In-Ko]

ADR-draft: https://github.com/openmcp-project/docs/blob/adr/cluster-api/adrs/cluster-api.md

[reshnm]

Missing/Open points have been discussed and decided. ADR will be updated to reflect these changes.
After ADR has been updated, implementation tasks can be created/updated to develop the first cluster providers.