To maintain a historical record of what was running in Google Cloud Platform at any point in time, you should use Forseti Security to automate inventory snapshots. Forseti Security is an open-source toolkit that helps to automate security and compliance in GCP by taking inventory snapshots of GCP resources.

Step-by-Step:

Install Forseti Security:

Follow the installation guide to deploy Forseti Security on your GCP environment.

Configure Inventory:

Set up the inventory module in Forseti to capture and store snapshots of GCP resources.

Schedule Snapshots:

Use Forseti’s configuration to schedule regular inventory snapshots.

Access Historical Data:

Review and access historical records through Forseti’s dashboard or by querying the Forseti database.

Compliance and Monitoring: Use Forseti to ensure compliance and monitor changes over time.