A master image that will be used to deploy machines for a Citrix Virtual Apps...

The Virtual Delivery Agent (VDA) is a software component that enables machines to deliver applications and desktops to users. The VDA registers with a Delivery Controller and communicates session information to the Controller, which brokers connections between users and their resources. Users access their resources through Citrix Workspace app or a compatible web browser1

1: Virtual Delivery Agent (VDA) | Citrix Virtual Apps and Desktops 7 2308