Description of problem:

Some engine VM specific configuration can be achieved using the help of a script
that the cloud-init will execute. e.g register your engine VM to dynamic dns service so the setup env could resolve it:

1. during setup pass file or text. No validation should be made on the input.
2. input passes as runcmd: section -
      
   runcmd:
    - [ curl, x.x.x.x://register.sh ]

3. cloud init should run it.