ELB supports layer-4 load balancing, which would just multiplex inbound TCP connections (with an added bonus of offloading TLS), but I'm concerned about losing client IP addresses. ELB actually has a way to address this with HAProxy's PROXY protocol:
http://www.haproxy.org/download/1.6/doc/proxy-protocol.txt
However, I haven't found a place for setting up the PROXY protocol support in undertow. Has anyone done this? Is there a way I should be going about it?
We should probably add support for haproxy's protocol if it has wide usage like this. It looks fairly straightforward.