If you use single-user subscriptions, then you have to sign in on each VM. And to do that, you need to run the Arnold License Manager, because Autodesk single-user licensing requires a user interface for the sign in. So probably you'll need to do something like ssh x-forwarding
If you use network licenses, the VMs have to be able to connect to your license server machine, wherever it is.
// Stephen Blair
// Arnold Renderer Support