When are subnets created in Auto Mode VPCs within GCP?

Subnets in Auto Mode VPCs within Google Cloud Platform (GCP) are created automatically in each region when the VPC is initially set up. This approach allows users to quickly provision resources across multiple regions without needing to manually define subnets for each one. The auto mode simplifies network management by automatically creating one subnet per region, each with a predefined IP range.

This automatic subnet creation process is particularly beneficial for users looking to quickly deploy applications that may require resources in multiple geographic locations, as the infrastructure can be established with minimal configuration. When a new region is added to an Auto Mode VPC, it automatically receives a subnet, making it easier for organizations to scale their cloud architecture seamlessly.

The other choices do not reflect the behavior of Auto Mode VPCs: subnets are not created solely based on user action, nor are they created only when traffic exceeds a certain limit, and while the automatic creation does span across regions, it specifically occurs during the initial setup rather than being an ongoing or reactive process.