In traditional monolithic architecture, applications already knew where the backend services existed through static hostnames, IP addresses, and ports. The IT operation team maintained the static configurations for service reliability and system stability. This Day 2 operation has significantly changed since microservices began running in distributed networking systems. The change happened because microservices need to communicate with multiple backend services to improve load balancing and service resiliency.
The microservices topology became much more complex as the service applications were containerized and placed on Kubernetes. Because the application containers can be terminated and recreated anytime by Kubernetes, the applications can't know the static information in advance. The microservices don't need to be configured with the static information of the backend applications because Kubernetes handles service discovery, load balancing, and self-healing dynamically and automatically.