At the core of the Agility product is the Virtual Deployment Description Language (VDDL). VDDL is an XML based technology for describing application composition. It allows the user to describe the way in which components of a system are connected and also to model the explicit requirements for each system component.
VDDL gives users the power to define the total environment in which their application components should run. As an example of what is possible, users can specify that their applications should: use a specific version of an Application Server, run on a particular Operating System or be connected to a particular database. This declarative approach not only allows an enterprise to model how their applications are constructed, it also allows the Agility product to realize complex dynamic deployments.
The diagram above shows the features of VDDL in action. A user requests the type of application they require via a Deployment Description. The IT infrastructure that Agility can use to provision the application is described to it via a Service Environment Description. Agility matches the application requested by the user with a set of deployable software components defined within a Product Description. With this match made, Agility begins the provisioning process. Deployment time is minimized as Agility only deploys what is necessary, making use of already running software and hardware. Agility's intelligent requirement-matching process provisions application components to the optimal location, subject to the explicit demands of policy.
