The below is real world Nexus 1000v archicture design based on Cisco UCS.
Architecture Assumption: vCenter will run wthine the UCS system
Key Points:
Two VSMs will work in active-standby way mode. VMware anti-affinity rule is applied to make sure that active VSM and standby VSM run on different host.
VMware vSwitch is used to provide the connectivity for VSM to avoid the "Chiken and Egg" scenario when the whole UCS is down.
Mac-pinning is used for Nexus1000v uplink load sharing.