I've been messing around with Apache as a load balancer for my Socket.io server. I went through the following topic and now everything seems to be fine.
Configuring Apache 2.4 mod_proxy_wstunnel for Socket.IO 1.0
I configured Apache using the following config and now the connections are being upgraded to WebSocket. But when I try to enable sticky sessions for the following config, it seems like sometimes apache routes the upgrade request to route #2 while the polling was established on route #1. When this happens, upgrade fails and websocket is not connected. Since we have to balancers (one for http and one for ws), I thought maybe the cookie set by http route #1 , cannot be accessed by ws routes and that's why sessions are not sticky among http and ws.
I'm using apache 2.4.9
<VirtualHost *:8080>
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
ProxyRequests off
ServerName localhost
<Proxy balancer://http-localhost/>
BalancerMember http://localhost:8081 route=1 keepalive=On smax=1 connectiontimeout=10 retry=600 timeout=900 ttl=900
BalancerMember http://localhost:8082 route=2 keepalive=On smax=1 connectiontimeout=10 retry=600 timeout=900 ttl=900
ProxySet lbmethod=byrequests
ProxySet stickysession=ROUTEID
</Proxy>
<Proxy balancer://ws-localhost/>
BalancerMember ws://localhost:8081 route=1 keepalive=On smax=1 connectiontimeout=10 retry=600 timeout=900 ttl=900
BalancerMember ws://localhost:8082 route=2 keepalive=On smax=1 connectiontimeout=10 retry=600 timeout=900 ttl=900
ProxySet lbmethod=byrequests
ProxySet stickysession=ROUTEID
</Proxy>
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/socket.io [NC]
RewriteCond %{QUERY_STRING} transport=websocket [NC]
RewriteRule /(.*) balancer://ws-localhost/$1 [P,L]
ProxyPass /socket.io balancer://http-localhost/socket.io
ProxyPassReverse /socket.io balancer://http-localhost/socket.io
</VirtualHost>