We have 3 physical servers (each with 1 NIC) in different datacentres, all of them are interconnected by openvpn bridged private network (10.x.x.x).

Inside this network we have fully functional 3 nodes Proxmox 2.1 cluster. So, actually question is:

Is there any "proper" way to make "global" local network (172.16.x.x) for all VMs inside cluster, so even if we move VM from one node to other we could reach it by static IP regardless of it's physical location?

BTW, we can't add dedicated NIC to each server.

Thanks in advance.

EDIT:

I have tried to make a separate openvpn bridge for 172.16.x.x, now I have at each server two interfaces:

SRV1:
openvpnbr1 - 172.16.13.1
vmbr0 - 172.16.1.1

SRV2:
openvpnbr1 - 172.16.13.2
vmbr0 - 172.16.2.1

But now there is no connection between those ifaces:

SRV1:
ping 172.16.13.2
From 172.16.1.1 icmp_seq=2 Destination Host Unreachable

SRV2:
ping 172.16.13.1
From 172.16.2.1 icmp_seq=2 Destination Host Unreachable

If I shut down vmbr0 interfaces, so there is connection between servers over openvpn, but vmbr0 is used by Proxmox...

Where I am wrong?