I’m doing some lab work with my team at the moment and we were gifted some hardware to do some multi region validation. Both systems (a VxRack SDDC & a VxRail) are in 2 separate datacenters, and both are using private IP addressing that is not routable between datacenters. As part of the validation we need both systems to be able to communicate with each other, however we dont control the inter lab switching to put in place the necessary routes to enable this. Rather than go through a change control process with the keepers of that gate we decided to get creative and have some fun (and hopefully learn something!) by setting up an NSX IPSec VPN between the labs.
Disclaimer: There are many better ways to do this for a permanent lab setup (i.e. BGP to the core with routes) but this was done on borrowed kit that was never initially designed with inter lab routing as a requirement, with no direct control on the inter lab switches, and we would also like to put it back the way we found it so dont want to make sweeping architectural changes!