Ensure you are in the correct VDC
vpc domain 1
Configure vPCpKL - peer keep-alive link.
Note: this is done while under "vpc domain
Note that it highly recommended that the keep-alive link be configured using a separate VRF such as the mgmt 0 mechanism.
Create the vPCpL - peer-link
Note: this is done under the interfaces on each switch that are going to participate in the domain.
interface port-channel 20
Enable vPC on the unlink/downlink interfaces on particpating switches