We have a web server and a client, both written in go, that interact with each other. We want HAProxy to load balance requests between several instance of the server, but it's not working. The client will always connect to the same server while it's still up.
If I look at the output of "netstat -anp", I can see that there is a persistent connection that was established between the client and the sever through HAProxy. I tried setting the Connection Header in the response to "close", but that didn't work at all.
Needless to say, I'm completely confused by this. My first question is, is this a problem with the client, server, or HAProxy? How does one force the client to disconnect? Am I missing something regarding this? Curl works fine, so I know that HAProxy does load balance, but curl also completely shuts down when finished, hence why I'm suspecting it's the persistent connection that's causing me issues since the client and server are long running.
Just as an FYI, I'm using go-martini on the server.
Thanks.
HTTP/1.1 uses KeepAlive by default. Since the connections aren't closed, HAProxy can't balance the requests between different backends.
You have a couple options:
Force the connection to close after each request in your code. Setting Request.Close = true on either the client or the server will send a Connection: close header, telling both sides to close the tcp connection.
Alternatively you could have HAPoxy alter the requests by setting http-server-close so the backend is closed after each request, or http-closeto shutdown both sides after each request.
http-server-close is usually the best option, since that still maintains persistent connections for the client, while proxying each request individually.