Outside in monitoring for Kubernetes is possible, if you are just doing poke tests. But if you are looking to collect pod and node metrics you have to do it from within the cluster. My understanding a general metrics collection for Kubernetes is:
- node-exporter type agent per node.
- singleton prometheus or similar service, pulls from node exporter, forwards to backend (mimir, thanos, etc)
- Singleton prometheus can also pull from service metrics based on service discovery.
None of this can be easily done from outside.