Services, Load Balancing, ExternalDNS, and Global Balancing

Before systems like Kubernetes were available, scaling an application often required a manual process that could involve multiple teams, and multiple processes, in many larger organizations. To scale out a common web application, you would have to add additional servers, and update the frontend load balancer to include the additional servers. We will discuss load balancers in this chapter, but for a quick introduction to anyone that may be new to the term, a load balancer provides a single point of entry to an application. The incoming request is handled by the load balancer, which routes traffic to any backend server that hosts the application. This is a very high-level explanation of a load balancer, and most offer very powerful features well beyond simply routing traffic, but for the purpose of this chapter, we are only concerned with the routing features.

When you deploy an application to a Kubernetes cluster, your...