Switch to Kubernetes EndpointSlices API

[jnoordsij]

Welcome!

• Yes, I've searched similar issues on GitHub and didn't find any.
• Yes, I've searched similar issues on the Traefik community forum and didn't find any.

What did you expect to see?

In my search of figuring out how exactly Service/Pod traffic is distributed, I noticed that Traefik internally uses the Kubernetes Endpoints API. As of Kubernetes 1.21, the EndpointSlices API is a stable alternative described as:

Kubernetes' EndpointSlice API provides a way to track network endpoints within a Kubernetes cluster. EndpointSlices offer a more scalable and extensible alternative to Endpoints.

Both from a performance and future-proof point of view, it might therefore be benificial to switch towards using this API.

A possible source of inspiration may be kubernetes/ingress-nginx#8890, which implemented this for (Kubernetes) NGINX.

[jnoordsij]

A WIP attempt can be found at https://github.com/jnoordsij/traefik/tree/migrate-to-endpointslices. This is far from finished, not passing tests yet, but seems to be heading in the right direction. Also this should probably rebased to master.

[kevinpollet]

Hello @jnoordsij,

Thanks for opening the issue,

When you have something ready feel free to open a pull request.
As this is an enhancement, the pull request has to be opened on the master branch.