Gardener apiServer: missing enforcement of private-only mode across clouds

Gardener apiServer: Private‑Only Enforcement

The Gardener apiServer configuration can restrict access to a shoot cluster’s Kubernetes API server, but the default behaviour leaves the endpoint exposed via a cloud provider load balancer. While the spec allows specifying network policies or firewall rules, the toggle to enforce a “private‑only” API server is not consistently applied across all supported clouds. This raises a design decision: how to guarantee that the API server is never reachable from the public internet while still allowing the Gardener seed cluster to manage the shoot through its internal network.

Unresolved Decision Points

• Should Gardener provide a single boolean flag that automatically configures the underlying cloud’s security groups or firewalls to restrict the API server to the seed network?
• How can the system avoid locking out the seed cluster if the shoot’s network policy excludes the seed’s IP ranges?
• What fallback mechanisms exist for providers that require complex VPN or DirectConnect setups to achieve true private access?

Specific Questions

1. Is there a documented mechanism to enable a private‑only API server mode that works uniformly across AWS, GCP, and Azure?
2. What are the required seed‑side network allowances to maintain control plane connectivity when the shoot API server is restricted?
3. How does Gardener handle cases where the underlying cloud provider cannot expose a load balancer with internal-only access?