If a Cloud Foundation for VxRail instance is already running in the data center, you can decide if you want this new instance to join the existing vCenter SSO domain, or create a new vCenter SSO domain. It should be noted that when you join an existing SSO domain, it reduces the number of workload domains the Cloud Foundation on VxRail instance can support. This is due to the limitation of 15 vCenter instances supported in enhanced linked mode.