+1 for BGP/OSPF-based VIPs in a layer 3 network. It's 2018. No reason why you can't easily run a layer 3 network with rich routing protocols. Super easy.
You don't need application level "discovery" when the IP never changes; the network will tell you where it currently lives.
I'll take a layer 3 network over raft/consul any day and all night.
I don't think I've ever heard BGP described as "easy", but then again it's not really my area.
Where could I go to read up on this without being a networking expert? Are there any safe ways to play with BGP in a lab environment? How expensive would said lab be to set up?
Are there any safe ways to play with BGP in a lab environment?
actually there are multiple ways of running bgp in a lab.
there are cheap variants that are routed into the internet with ipv6 and there are ways to just play without without talking to the outside network.
How expensive would said lab be to set up?
it heavily depends on what you want.
for a high available lab you would of course need multiple nodes/routers, depends on what you want to do.
Network people who understand BGP are cheaper and easier to find than someone who actually knows how Consul/raft works. You might think you know how consul works, but do you really? Consul and raft have caused several high profile outages -- including at places full of smart people like Amazon. If Amazon can't do it right, what chance do you have?
Especially when there are several-year old bugs open against consul, where it just completely loses consensus and can't deal with losing a single node(0)
You don't need application level "discovery" when the IP never changes; the network will tell you where it currently lives.
I'll take a layer 3 network over raft/consul any day and all night.