After a recent discussion with Marvin from the KCP team, I found out, that the fork of the controller-runtime that was previously used to foster a KCP integration will not be maintained anylonger and should be replaced by the new mutlicluster-runtime.

The multicluster-runtime is mainly a drop in replacement with some additional features on top that help to manage different shards in the future. An example how a controller would be written with the new library can be found here:

https://github.com/kcp-dev/multicluster-provider/tree/main/examples/apiexport.

The task would consist of ensuring that the account-operator is able to work as is, with replacing the current controller-runtime based implementation with the mutlicluster runtime.

It would be great to achieve this migration with as little change needed as possible, especially in the shared library. With the help of the local-setup the implementation should be able to be validated quite well.

The upstream codebase of the mutlicluster-runtime can be found here: https://github.com/kubernetes-sigs/multicluster-runtime