Recently, I was asked to implement vPC connections over Dark Fiber between two data centers. Is this possible, and, if it is possible, does it have any drawbacks or limitations? I'm asked to encrypt the data involved in the vPC using MACsec. I know it is a very hard task, but any help would be useful.
Three words: Don't do it.
There are many reasons why, but the most important is that instead of making resilient links, you have made both data centers vulnerable to the same problem. If the VPC link goes down, both data centers will think they're active. That almost certainly means that nothing will work until you restore the link. Not exactly a robust system is it?