An application definition is a rule or pattern by which a collection of connected virtual machines are identified as a deployed application instance. An application instance is a set of connected virtual machines that matches an application definition.

During the discovery process, the virtual machines, the services running on the virtual machines, and the components deployed on the virtual machines are compared to application definitions. Each set of connected virtual machines that matches an application definition is considered an application instance.

If you have Microsoft Exchange installed, each Exchange role is a service for which you can create application definitions. When you are creating a rule and you select Mail Server as the server category, each of the Exchange roles are listed under Service Name,

The Manage tab of the vRealize Infrastructure Navigator virtual appliance displays the application definitions management table. The application definitions management table shows all the application definitions that exist under a vCenter Server, and all the Exchange roles.

On the Services tab in the information panel at the bottom of the screen, you can view the Microsoft Exchange name and version number of a role, and a list of the ports on which listening occurs. You can also view this information in the vRealize Infrastructure Navigator portlet on the Summary tab.