Question

Difficulty: Very hardDeploying Cloud Load Balancers and Configuring Cloud DNS

A system administrator has deployed a private Cloud DNS zone named services.internal in a host Google Cloud Virtual Private Cloud (VPC) network named vpc-production. A separate analytics workload runs in another VPC network named vpc-analytics within the same organization. Compute Engine instances located in vpc-analytics are currently unable to resolve domain names ending in .services.internal. You need to enable domain name resolution for instances in vpc-analytics while minimizing infrastructure complexity and avoiding unnecessary DNS peering overhead. Which configuration step must be performed to meet this requirement?

  1. Update the existing services.internal private DNS zone configuration in Cloud DNS to add vpc-analytics to the list of authorized VPC networks.Answer
  2. B
    Establish VPC Network Peering between vpc-production and vpc-analytics, as private Cloud DNS zones automatically sync across peered VPC networks.
  3. C
    Enable the Cloud DNS API in the host project for vpc-analytics and create a DNS peering zone in vpc-production that targets vpc-analytics as the peer network.
  4. D
    Add a custom egress VPC firewall rule in vpc-analytics with priority 65535 allowing UDP port 53 traffic to the internal metadata IP address of vpc-production.

Answer

Update the existing services.internal private DNS zone configuration in Cloud DNS to add vpc-analytics to the list of authorized VPC networks.
In Google Cloud DNS, a private DNS zone can be made accessible to multiple VPC networks by adding those networks to the zone's authorized networks list. Once authorized, instances in vpc-analytics can resolve hostnames in services.internal directly through their local metadata DNS server.

Step-by-Step Solution

1
Identify the requirement for cross-VPC private DNS resolution
Determine that instances in vpc-analytics need to resolve records managed by the private DNS zone hosted in vpc-production.
Cloud DNS private zones are restricted by default to only the VPC networks explicitly authorized during or after creation.
2
Evaluate GCP Cloud DNS multi-VPC binding capabilities
Confirm that a single private Cloud DNS zone can be authorized for multiple VPC networks across the same organization.
Direct authorization allows all VMs in the authorized VPCs to query the private zone via their local metadata server (169.254.169.254) without additional DNS forwarding or peering configurations.
3
Select the optimal configuration modification
Add vpc-analytics to the authorized networks list of the services.internal private zone.
This is the standard, simplest, and most efficient method to grant cross-VPC DNS resolution access.

Key Concept

Cloud DNS Private Zone Authorized Networks
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