I have an external regional load balancer running on a shared VPC in project A and have backend services attached to it from project B and C. I would like to add Cloud Armor to my Cross-project backend services (NEG) from project B and C. But when I try to apply the security rule to a target it does not provide me with the option for one of my cross-project backend services.
I know GCP has only introduced the feature for cross-project backend services in external loadbalancer in 2022 so my guess would be that this feature does not exist yet. Though if so, are they still planning to add this functionality?
Adding Cloud Armor To Cross-Project Backend Services is still under enhancement mode. You can refer to the Feature request . Do upvote this Feature Request to get future updates on this case and Search for or create issues and feature requests, by product.
As now this FR is pending with the product engineering team, currently there is no ETA. You can learn more about cross-project service referencing in the following link.