I am trying to wrap my head around this (very) simple issue of IP failover from one physical location to another. I have a few Virtual machines running at Site A where I need to rebuild the NAS. In order to do so I want to vMotion/move these VM(s) to site B but want to retain the IP addresses of the VMs/Network configuration. SiteA and SiteB's routers have a GRE tunnel between them and I defined static route for the next-hop of the IP being migrated.
In order for this to work, I have created a virtual interface on Site B's routerB and use the same gateway IP address which the VM is expecting. It works fine but when I try to access any machine from the same subnet from migrated VM, I can't do so because my requested subnet is physically not present on router B. It falls under /24 broadcast domain of the subnet on router B.
NSX solved this problem with VxLAN but What is the alternative to achieve IP failover across multiple datacenters? I run BGP on both locations and running over Brocade NetIron routers. I was thinking to create a MPLS cloud over my exiting IP network and have a virtual router interface defined accessible from both routers A and B? Or some sort of extended VLAN?
Or I would say I have 2 sites, 2 routers, I need to have a extended LAN between both sites so I can use 1 IP address from any of the locations at the same time.