Clearly, using deployment manager seems like quite a task given all of this. Here, though, is what you should be sure to remember about IAC:

• Managed Instance Groups are a powerful construct for autohealing and autoscaling groups of GCE VMs
• Infrastructure as a Code allows us to provision infrastructure using template files that can be reused, composed, and checked into source control
• Google's Cloud Deployment Manager offers an IAC framework using YAML configuration files, potentially parameterized using Jinja or Python
• Google's IaaC offering, Deployment Manager, is not quite on the same level of capabilities as the current segment leader (Terraform), but it is getting there