The short question is how can be set the timeout for an upstream for persistent connections (using keepalive) - looks like they never timeout.

Details:

I have a configuration where i need to setup a reverse proxy for SSL connections, and reuse the backend SSL connections. For doing this i'm using the keepalive directive on the upstream, something like this:

...
upstream backend {
server backend-host.com:443;
keepalive 10;
}
...

backend-host.com is hosted on Amazon AWS and consists of an Elastic Load Balancer. This means that from time to time its IP will change (scaling up and down)

My issue is that witth the current configuration the persistent connections are never refreshed (they don't have a timeout) and when the IP of the ELB changes then the nginx reverse proxy stops working.

Let me know if more info is needed.