distributing gateway over two sites

Hi,

If you are familiar with Cisco ACI or VMware NSX, you know that if you have stretched a vlan over two sites (with vxlan), the default gateway of this subnet is distributed on all leafs (ACI) or all hosts (NSX). So the servers in site A use the gateway of site A and same thing with site B.

Now I have this client who want to stretch a vlan over two sites with vxlan and EVPN with Nexus 9000. No ACI or NSX, he wants to do hardware VTEP interfaces in NX-OS.

Now, how do you distribute the default gateway over these two sites without ACI/NSX ? If you do HSRP over two sites, only one will be active (no vpc), so it's not good. GLBP load balance between routers but you can't specify that site A uses router 1 only and site B uses router 2 only.

So I'm looking for a way to have a subnet stretched over two sites with default gateway being on these two sites simultaneously so that server don't have to cross the WAN to be routed. Like NSX and ACI can do but without them.

BTW, the WAN links between sites are low latency (less then 2 ms).

any idea to make this possible ?

thanks