Our devs are working on application where we need to frequently distribute small amounts of data to multiple locations which may change dynamically (servers may join and leave rather often). Some servers are on cloud providers like AWS, DO, some are HW in IDC.
I've been tasked with finding a reasonable solution to this. I am thinking whether it is possible to create a subnet on top of IPSec VPN (using openswan/libreswan). I know that I can setup routing between different subnets joined via VPN, however that is rather a manual job. In light of those servers coming and going often it would be rather hard to do. So I am wondering if it would be possible to utilize VPN setup (preferably IPSec, or possibly OpenVPN) to organize those servers into single "virtual LAN" with it's own subnet range and being able to connect IPs within this subnet (and possibly also use broadcast address?).