I just restricted the Debian 10 Buster Cloud VPS image to the Toolforge project. Puppet 7 packages aren't available for Buster and it won't be possible to enroll new Puppet 5 clients to Puppet 7 based infrastructure.
I did however allow the Toolforge project to access the image, as I suspect we might need to provision new K8s nodes (and decom some grid nodes) using Buster as running them on newer OS versions still needs some more setup and testing.
Further details are on the task https://phabricator.wikimedia.org/T351499.
Taavi