Question

Difficulty: HardProvisioning Compute Engine and Kubernetes Engine Clusters

An enterprise logistics company is provisioning a private Google Kubernetes Engine (GKE) cluster to process high-throughput batch analytics workloads. Security compliance mandates that worker nodes must only have private IP addresses and that administrative access to the GKE control plane endpoint must be restricted strictly to an internal management subnet accessible via Cloud Interconnect. During deployment testing, engineers notice that while worker nodes lack public IP addresses, the cluster control plane public endpoint remains accessible from unauthorized external networks. Which configuration change must be implemented to fulfill the security compliance requirements?

  1. Enable Control Plane Authorized Networks on the GKE cluster and restrict authorized CIDR blocks exclusively to the internal management subnet range.Answer
  2. B
    Rely on the private cluster configuration alone, assuming that disabling public IPs on worker nodes automatically restricts network access to the GKE control plane.
  3. C
    Assign the primitive Owner IAM role (roles/owner) to the management subnet service account to enforce perimeter network restrictions on the control plane.
  4. D
    Re-architect the workload to run on an unmanaged Compute Engine Managed Instance Group (MIG) because private GKE clusters cannot restrict control plane administrative endpoints.

Answer

Enable Control Plane Authorized Networks on the GKE cluster and restrict authorized CIDR blocks exclusively to the internal management subnet range.
Enabling Control Plane Authorized Networks on a private GKE cluster allows organizations to specify explicit CIDR ranges (such as an internal management subnet) permitted to communicate with the cluster's control plane API server. This ensures that unauthorized public or internal networks cannot reach the cluster administration endpoints.

Step-by-Step Solution

1
Analyze the cluster security requirements
Worker nodes must remain private and administrative access to the GKE control plane must be constrained to specific internal IP ranges.
By default, creating a private cluster prevents public IP assignment on nodes but leaves the control plane endpoint reachable unless restricted.
2
Evaluate control plane security features in GKE
Control Plane Authorized Networks provide IP-based access control lists (ACLs) for the GKE control plane master endpoint.
Configuring Control Plane Authorized Networks explicitly blocks traffic originating from IP addresses outside the configured CIDR blocks.
3
Select the correct configuration option
Enable Control Plane Authorized Networks and set the allowed CIDR range to the internal management subnet.
This satisfies security compliance without requiring application re-architecture or granting overly permissive IAM roles.

Key Concept

GKE Private Cluster Control Plane Security & Authorized Networks
Estimated Time:2m 0s
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