Sample HA-Proxy configuration for load balancing SockJS running on Node.JS servers.

haproxy.cfg

global
    maxconn     10000 # Total Max Connections. This is dependent on ulimit
    nbproc      2

defaults
    mode        http
    option      redispatch
    maxconn     2000
    contimeout  5000
    clitimeout  50000
    srvtimeout  50000
    option      httpclose

frontend all 0.0.0.0:80
    timeout client 86400000

    acl is_api hdr_dom(host) -i api
    use_backend api_http_backend if is_api

    acl is_websocket hdr(Upgrade) -i WebSocket
    acl is_websocket hdr_beg(Host) -i ws
    use_backend ahd_socket_backend if is_websocket # Filter for Websockets
    default_backend ahd_http_backend

backend ahd_http_backend
    balance roundrobin
    cookie SERVERID insert indirect # Match requests to same machines, if possible
    option forwardfor # This sets X-Forwarded-For
    timeout server 30000
    timeout connect 4000

    server aas0 10.0.10.76:3000 weight 1 maxconn 5000 cookie AHDFE0 check
    server aas1 10.0.10.77:3000 weight 1 maxconn 5000 cookie AHDFE1 check
    server aas2 10.0.10.78:3000 weight 1 maxconn 5000 cookie AHDFE2 check

backend ahd_socket_backend
    balance roundrobin
    cookie SOCKETID insert indirect # Match socket requests to same machines, if possible
    option forwardfor # This sets X-Forwarded-For
    no option httpclose # To match the `Connection` header for the websocket protocol rev. 76
    option http-server-close
    option http-pretend-keepalive
    timeout queue 5000
    timeout server 86400000
    timeout connect 86400000

    server aas0 10.0.10.76:9000 weight 1 maxconn 5000 cookie AHDSCKT0 check
    server aas1 10.0.10.77:9000 weight 1 maxconn 5000 cookie AHDSCKT1 check
    server aas2 10.0.10.78:9000 weight 1 maxconn 5000 cookie AHDSCKT2 check

backend api_http_backend
    balance roundrobin
    cookie SERVERID insert indirect # Match requests to same machines, if possible
    option forwardfor # This sets X-Forwarded-For
    timeout server 30000
    timeout connect 4000

    server aas0 10.0.10.76:3001 weight 1 maxconn 5000 cookie APIFE0 check
    server aas1 10.0.10.77:3001 weight 1 maxconn 5000 cookie APIFE1 check
    server aas2 10.0.10.78:3001 weight 1 maxconn 5000 cookie APIFE2 check

listen stats :8080
    mode http
    stats enable
    #stats hide-version
    stats realm Haproxy\ Statistics
    stats uri /
    stats auth user:password