kubernetes data client support for cluster trust bundles

[szuecs]

Soon cluster trust bundles are GA and we can read it.
https://kubernetes.io/docs/reference/kubernetes-api/certificates/cluster-trust-bundle-v1beta1/

We can use it for cert validations for example in mTLS cases.

[AshrafAhmed9]

Hi @szuecs, I'd be interested in helping implement this. As I understand it, the goal is to have the Kubernetes data client read ClusterTrustBundle resources (certificates.k8s.io/v1beta1) and make the bundled CA certs available for cert validation, e.g. in mTLS cases. I'd start by reviewing how the data client currently fetches Kubernetes resources and drafting a design for watching/reading ClusterTrustBundles before implementing. Since this is a larger feature, would you be open to assigning it to me and giving early feedback on the approach? Thanks!

[szuecs]

@AshrafAhmed9 if you want to read a lot of code you can do it. AI will likely not help and we don't accept kubernetes client-go as dependency.
I am not sure if I need to build this soon or not. It depends a bit on my work on SPIFFE/SPIRE in one of our dev clusters.
If you want you can give this a shot. I can not promise that we will have the time to help you to merge this or I need to rush this. Likely you will have enough time, but I wanted to let you know before.

Feel also free to join https://app.slack.com/client/T029RQSE6/C82Q5JNH5 Go slack community channel #skipper and ask there. We have always something you can do if you like.