I have a situation with 2 seperate DC's that are to be interconnected via OTV to form a resilient pair supporting vmotion between DC's, DC-A and DC-B. Each DC has a pair of Nexus 7K's.
In this requirement I need HSRP in a particular vlan on DC-A to move to DC-B following a WAN failure in DC-A. So I plan to use HSRP with object tracking to monitor a WAN interface in DC-A to decrement the priority values in DC-A to become lower than those in DC-B when the tracked interface goes down. So far so good.
But, I now find that VPC is also used in both DC;s forwarding the server vlans, within each DC, not between the two. I know that VPC will forward traffic destined to an HSRP address regardless of the state of the HSRP priority.
My concern is that following a WAN failure in DC-A, HSRP priority moves to DC-B, but vPC in DC-A will still forward traffic, as it ignores the HSRP priority. I've seen this in DC's with a pair of Nexus chassis, with 2 interfaces in the HSRP group.
I've never seen this in a dual DC set up with 4 interfaces in an HSRP group, is the HSRP/VPC interaction still the same?
I know about filtering the HSRP messages across the OTV, but this isnt appropriate in this situation, I cannot have servers in a particular vlan active on both sites due to liberal use of stateful firewalls, it has to be one or the other.
