[EKS] [request]: Cedar for Kubernetes in Amazon EKS

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**Tell us about your request**
Integrate [Cedar access controls for Kubernetes](https://github.com/awslabs/cedar-access-control-for-k8s/) into Amazon EKS

**Which service(s) is this request for?**
EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
Kubernetes RBAC has well-known limitations in being allow-only (no denials), no conditions, and no attribute-based controls.

**Are you currently working around this issue?**
Many customers use Open Policy Agent/Gatekeeper, Kyverno, or K8s Validating Admission Policies to restrict permissions

**Additional context**
AWS open sourced [Cedar access controls for Kubernetes](https://github.com/awslabs/cedar-access-control-for-k8s/) ([blog post](https://www.cedarpolicy.com/blog/cedar-for-kubernetes)) in October 2024, but as authorization webhooks are not customer configurable in EKS (aws/containers-roadmap#1932), AWS would have to integrate Cedar into EKS for customers to use it.

Read the Cedar for Kubernetes project and its linked blog post first, then review aws/containers-roadmap#1932 about customer-configurable authorization webhooks in EKS. The request is complete when Cedar access controls are integrated into Amazon EKS so customers can use them.

Written by the indexing model from the issue text.