I find abstract concepts are easier to understand and follow when you can build on basic facts, tie in prior knowledge, and parallel abstract concepts with concrete examples. Generic Networking in a Kubernetes Context Understanding the how and why of basic concepts improves your ability to do quick solid evaluations of different tooling solutions, which is critical since no one has time to learn every tool in depth. If you take the time to deeply learn the fundamentals that advanced concepts are built upon you’ll be able to come up with multiple solutions to problems that don’t have a perfect how to guide readily available and evaluate which solution is best for a given situation. The point of the story is that trying to implement Kubernetes by relying on how to guides can cause you to learn the tool equivalent of a hammer and then see every problem as a nail. Exposing the Internal APIs over Ingress came about out of ignorance of the basics of Kubernetes / that was the only known way to interact with things in the cluster. It’s a valid solution, but I’d like to point out that the Internal APIs should have only been internally reachable using a ClusterIP service as this would have been both more secure and less complex. The External APIs were put behind an API Gateway as a means of bolting on authentication functionality, and the Internal APIs were firewalled to prevent them from being externally exposed. The architecture evolved to a point where both the Internal and External APIs were externally exposed using Kubernetes Ingress, firewall rules were implemented to limit access to both sets of APIs. Internal APIs were named such to make it obvious that it’d be dangerous to externally expose them as they were meant to house application middleware logic and backend database logic. The External APIs were to function as publicly reachable backend points of entry for the websites and act as potentially reusable building blocks for future projects. I’ve seen a project with 2 websites and 2 API Groups: Externally accessible APIs and Internally accessible APIs. If you read till the end of this series you’ll gain a deep understanding of the following diagram, Kubernetes Networking, the 7 service types, Kubernetes Ingress, and a few other fundamental concepts. Kubernetes Networking, Services, and Ingress

What is kubernetes networking