Custom properties are vRealize Automation-supplied properties. You can also define your own properties. Properties are name-value pairs used to specify attributes of a machine or to override default specifications.
You can use custom properties to control different provisioning methods, types of machines, and machine options as in the following examples:
Specify a particular type of guest OS.
Enable WIM-based provisioning, in which a Windows Imaging File Format (WIM) image of a reference machine is used to provision new machines.
Customize the behavior of Remote Desktop Protocol when connecting to a machine.
Register a virtual machine with a XenDesktop Desktop Delivery Controller (DDC) server.
Customize a virtual machine’s system specifications, such as adding multiple disk drives.
Customize the guest OS for a machine, for instance, by including specified users in selected local groups.
Specify network and security settings.
Add additional control options such as drop-down menus to make input and selection options available to the consumer at request time.
When you add a property to a blueprint, reservation, or other form you can specify if the property is to be encrypted and also if the user must be prompted to specify a value when provisioning. These options cannot be overridden when provisioning.
For an example of how to additional control options to dynamically set a custom property based on a consumer's selection from a list of predefined options, see the Adding a Network Selection Drop-Down in vRA 7 blog post.
A property specified in a blueprint overrides the same property specified in a property group. This enables a blueprint to use most of the properties in a property group while differing from the property group in some limited way. For example, a blueprint that incorporates a standard developer workstation property group might override the US English settings in the group with UK English settings.
You can apply properties in reservations and business groups to many machines. Their use is typically limited to purposes related to their sources, such as resource management. Specifying the characteristics of the machine to be provisioned is generally done by adding properties to blueprints and property groups.