It seems like Amazon et al have full-fledged SDNs while DigitalOcean is a little more primitive. Even customer-level VLANs are new. Prior to that, "private netw

It seems like Amazon et al have full-fledged SDNs while DigitalOcean is a little more primitive. Even customer-level VLANs are new. Prior to that, "private networking" was just a way to save on transit quota; you shared a LAN with everyone else in the datacenter. Speculating and recalling old memories here, but: floating IP is implemented as an additional IP on an existing interface. DHCP can't assign multiple IPs for the same MAC. So there's got to be some DigitalOcean magic in the base images to figure out that a floating IP is assigned and configure the interface for it. You might be able to replicate this yourself, they just don't want to be responsible for support. Perhaps over time they will grow a more complex network fabric that will enable floating IPs to be their own DHCP-enabled interfaces straight on VMs, instead of the "dumb" forwarding rules they appear to be today. But also perhaps the lack of such things is why DigitalOcean is cheaper than Amazon.