Question

Difficulty: MediumDeploying Cloud Load Balancers and Configuring Cloud DNS

Your enterprise organization has two Virtual Private Cloud (VPC) networks, `shared-services-vpc` and `application-vpc`, in the same Google Cloud project. You are deploying an Internal HTTP(S) Load Balancer in `application-vpc` to expose a microservice, and you need clients in both VPC networks to resolve the load balancer's internal IP address using a private DNS domain name (`internal.example.com`). Which of the following configuration steps are required to successfully deploy this solution? (Select TWO choices.)

  1. Authorize both `application-vpc` and `shared-services-vpc` in the Cloud DNS private zone network visibility settings.Answer
  2. Reserve and allocate a dedicated proxy-only subnet in the region where the Internal HTTP(S) Load Balancer is deployed.Answer
  3. C
    Enable the Cloud DNS API directly at the GCP Organization resource level to permit cross-VPC DNS resolution.
  4. D
    Apply IAM roles at the subnet level to override the default organization policy hierarchy for cross-VPC traffic.

Answer

To successfully allow private DNS resolution across multiple VPCs and deploy an Internal HTTP(S) Load Balancer, you must authorize both VPC networks in the Cloud DNS private zone settings and create a regional proxy-only subnet for the load balancer's Envoy proxies.
Authorizing both VPC networks in the Cloud DNS private zone configuration ensures that VMs in both networks can query and resolve internal DNS records. Creating a regional proxy-only subnet is a strict prerequisite for deploying an Internal HTTP(S) Load Balancer because Envoy proxies require IP addresses allocated from this dedicated subnet to forward requests to backend services.

Step-by-Step Solution

1
Configure Cloud DNS Private Zone Network Visibility
Both `application-vpc` and `shared-services-vpc` are attached to the Cloud DNS private zone (`internal.example.com`).
By default, a private DNS zone is accessible only by authorized VPC networks in the project.
2
Allocate a Proxy-Only Subnet
A regional proxy-only subnet is created with an appropriate CIDR range (e.g., `/26` or larger) in the target region.
GCP regional Internal HTTP(S) Load Balancers require a proxy-only subnet to instantiate Envoy proxy instances that handle Layer 7 traffic routing.

Key Concept

Cloud DNS Private Zone Authorization and Internal HTTP(S) Load Balancing Subnet Requirements
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