I'd like to manage my application as follows:
So for example, let's say I manage mydomain zone in Project A, with www.mydomain.com, app.mydomain.com and staging.mydomain.com CNAME records configured there.
In Project B I manage one Cloud Run service, staging-service.
In Project C I manage two Cloud Run services, www-service and app-service.
How can I map the services from Project B or C to the domains/subdomains in Project A?
Thanks for the help!
DNS does not care which projects your resources are in. You can create DNS resource records for supported resources located in any project. DNS is a hostname to IP address translation service.
When mapping custom domains in Cloud Run, you will be presented with DNS resource records to create. Those records are IP/CNAME based.
Your will first need to verify site (domain) ownership for each project that you wish to use custom domains or certificates:
Cloud Run: Add verified domain owners to other users or service accounts