WebSockets with Varnish and Nginx

Not only that, but letting all traffic through Varnish is not a good utilization of its resources at all.

The question is, how could I set up multiple servers on the same port? Or what else do I need to put in front of Varnish to route WebSocket connections elsewhere?

I'm starting to think this use case is not easy to solve under one IP address.

I don't see why Varnish would create one thread per allocation. They are using epoll/kqueue on an accept thread to handle new incoming requests. The requests themselves are handled by worker thread pool.

To clarify (and answer @sureshv), Varnish allocates one worker-thread per session (active connection), but those threads are pooled by the managed thread pool @sureshv referred to. It's recommended to leave the thread_pool value at 2 and scale the thread_pool_min and _max values to suit your traffic.

As for the handling of the websockets, setting the pipe_timeout variable in the vcl file would release any persistent, yet silent, connections.

nginx can compress your HTTP traffic, while Varnish can't. So there are some things you would need nginx for.

However, I really think that nginx should implement proper support for WebSockets by now. I have requested this previously, but the request got unanswered.

I would think nginx would be better for holding open long "keep alive" connections than Apache or IIS if you are doing long polling etc.

Of course if you are just forwarding to another backend you may lose this.

Well, the sample is incomplete. Often, you also need a server for serving static files, which Nginx is really good at, but Varnish cannot do.

So how do you handle the case of SSL in front of web traffic and web socket traffic? I need to handle both SSL and non-SSL. Right now I just use another port, but my users behind a firewall can't access the websocket.