An operations engineer wants to enable Cloud CDN for an existing HTTP(S) service but the service currently uses an Internal HTTP(S) Load Balancer. What is the correct limitation to communicate?

Cloud CDN is designed to cache content at Google's edge locations globally, serving users closest to them. This functionality inherently requires a publicly accessible entry point, which is provided by an External (global) HTTP(S) Load Balancer. Internal HTTP(S) Load Balancers operate within a Virtual Private Cloud (VPC) network and are not exposed to the public internet, making them incompatible with Cloud CDN's global distribution model. Therefore, Cloud CDN cannot be enabled on an internal load balancer. There is no concept of a separate internal CDN endpoint for Cloud CDN, nor is Cloud CDN limited to only Cloud Storage backends; it can work with various backend services exposed via an external HTTP(S) Load Balancer.