You are configuring a CI pipeline.

Cloud Build Private Pools allow your builds to run in a secure, isolated environment with direct access to resources inside your private VPC network, without exposing them to the public internet. This is the Google-recommended approach for minimizing management overhead while maintaining strong security boundaries.

From the official documentation:

"Private pools run your builds in a dedicated and secure environment that can connect to private network resources."

— Cloud Build Private Pools Overview

"You can configure private pools to access resources in a VPC network, which enables secure access to services without using public IPs."

— Accessing Private Resources

This method eliminates the need to create and manage additional compute instances or complex load balancing setups, providing seamless integration with your private services during CI pipeline execution.