When deploying VxRail, you can use an existing "customer-provided" vCenter server or a new "VxRail-provided" vCenter server. If you use an existing vCenter server, the server must be reachable on the VxRail External Management network during VxRail deployment.
The example in this document uses the VxRail-provided vCenter server that is deployed with VxRail on one of the VxRail nodes. This location provides the vCenter with the fault tolerance provided by the stretched cluster.
Note: Since a new vCenter is automatically deployed with VxRail, there is no need deploy a new vCenter to esx-svcs01 as shown in the SmartFabric Services with Multisite vSAN Stretched Cluster Deployment Guide.