vRA 8.1 |Hostname| OOTB

The specified template will substitute the auto-generated machine names. Make sure the template generates unique names for this project, otherwise the deployment may fail if a machine with the same name already exists. Here are the available properties to use: 
Resource properties: includes the resource name from blueprint template, custom properties assigned to the resource (from blueprint, project, etc.). e.g. ${resource.image}, ${resource.name}
Endpoint properties: use any endpoint or custom property assigned to the endpoint e.g. ${endpoint.endpointType} 
Project properties: name and description e.g. ${project.name} 
User name, user: ${userName}, ${user} 
Number generator: add digits to generated names to make them unique. ${######} adds 6 digits.