I can not find the use-cases this might answer, is this supposed to replace IaC tools such as ansible or Terraform?
AFAIK using standard GCE instances and updating them or re-rovisioning them is a quite cheap operation, I'm not sure where this stands in the whole "pet vs cattle" spectrum.
I could be missing something, I am genuinely curious about this new product.
VM Manager is three separate services, one of which is "OS config management", which is more akin to Ansible (or Puppet, Chef, etc), i.e. provisioning software on a system. The other two services look after themselves TBH.
The OS config mangement in practice is a daemon that polls for "guest policies" every 10 minutes. Their example policies will give you a good idea of what it does:
