Hi Luke, I've place an nginx instance after my local haproxy dev config, and found something which might explain what you're observing : the process apparently leaks FDs and fails once in a while, causing 500 to be returned :
2019/01/23 08:22:13 [crit] 25508#0: *36705 open() "/usr/local/nginx/html/index.html" failed (24: Too many open files), client: 1> 2019/01/23 08:22:13 [crit] 25508#0: accept4() failed (24: Too many open files) 127.0.0.1 - - [23/Jan/2019:08:22:13 +0100] "GET / HTTP/2.0" 500 579 "-" "Mozilla/4.0 (compatible; MSIE 7.01; Windows)" The ones are seen by haproxy : 127.0.0.1:47098 [23/Jan/2019:08:22:13.589] decrypt trace/ngx 0/0/0/0/0 500 701 - - ---- 1/1/0/0/0 0/0 "GET / HTTP/1.1" And at this point the connection is closed and reopened for new requests. There's never any GOAWAY sent. I managed to work around the problem by limiting the number of total requests per connection. I find this extremely dirty but if it helps... I just need to figure how to best do it, so that we can use it as well for H2 as for H1. Best regards, Willy