Create a Discovery Controller that adds service/instance information in config maps

To eliminate the need for the application to be able to access the K8S API server we should provide a ServiceDiscovery implementation that does not rely on the use of the API.

We could do this by just leveraging the platform service discovery and then fetch the port via a lookup.

Another option would be to implement a service discovery server which exclusively talks to the k8s api server and have clients fetch service information from this server (kind of like a eureka server).

[markfisher]

I think the best way to do this (without the Pod contacting the API) would be to provide a Kubernetes controller that uses a shared Informer to capture all the events about services and act as a ServiceRegistry.

I agree, but I would first explore the ecosystem for existing projects. I would also expect that implementing an Informer-driven ServiceRegistry would be simpler/lighter in Go.

[spencergibb]

https://github.com/scratches/spring-controller (native, config maps) and https://github.com/Haybu/spring-cloud-k8s-eureka-controller (discovery) can be useful proofs of concept to take from.