HAProxy 配置
# Reference: http://blog.haproxy.com/2012/11/07/websockets-load-balancing-with-haproxy/
listen chat
bind *:80
default_backend nodes
backend nodes
option httpchk HEAD /health
http-check expect status 200
cookie io prefix indirect nocache # using the `io` cookie set upon handshake
server app01 app01:3000 check cookie app01
server app02 app02:3000 check cookie app02
server app03 app03:3000 check cookie app03