Description of problem:

Currently we are using these proxy timeout settings for all services:
defaults
  log  global
  maxconn  4096
  mode  tcp
  retries  3
  timeout  http-request 10s
  timeout  queue 1m
  timeout  connect 10s
  timeout  client 1m
  timeout  server 1m
  timeout  check 10s


Both glance, heat has an API call which haves the service to connect to an external service: for Ex.:
 
time glance --os-image-api-version 1  image-create --disk-format=qcow2  --container-format=bare --copy-from=http://example.com
504 Gateway Time-out: The server didn't respond in time. (HTTP N/A)

real	1m1.020s
user	0m0.531s
sys	0m0.095s


glance does not needs to save the full url, before it returns, but it wants have at least a HEAD. 


BTW, Long responding API calls also possible, when you for ex. asking something about 10k item.


In my case the server was not responded in time, because first it tried on IPv6 (I have no external IPv6 connectivity, just local), but it can be delayed by any other reasons. (iptables DROP ..)

I would not notice the issue, beside it is slow if the proxy timeout would be 3 minute.

Actual results:
The haproxy is inpatient, or the services does not have built in response deadlines.
 

haproxy disconnects from the backend server before it generates the response,
and returns with 504 to the client instead of the real response.


The Glance api log has this kind of traces :
2016-11-03 07:33:35.043 12918 INFO eventlet.wsgi.server [req-749fa599-f55a-432b-aac7-966fcb5381c4 cab7f2d4f87e46a493775b3fc87be0d4 2ab73c577de146f2816b311485b63340 - default default] Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/eventlet/wsgi.py", line 512, in handle_one_response
    write(b''.join(towrite))
  File "/usr/lib/python2.7/site-packages/eventlet/wsgi.py", line 453, in write
    wfile.flush()
  File "/usr/lib64/python2.7/socket.py", line 303, in flush
    self._sock.sendall(view[write_offset:write_offset+buffer_size])
  File "/usr/lib/python2.7/site-packages/eventlet/greenio/base.py", line 385, in sendall
    tail = self.send(data, flags)
  File "/usr/lib/python2.7/site-packages/eventlet/greenio/base.py", line 379, in send
    return self._send_loop(self.fd.send, data, flags)
  File "/usr/lib/python2.7/site-packages/eventlet/greenio/base.py", line 366, in _send_loop
    return send_method(data, *args)
error: [Errno 104] Connection reset by peer


When I directly connect to the backend server, 
It worked in 130 sec.

Expected results:

haproxy does not breaks the connection to backend server, when the server is able to response.  1 minute without response does not means the server is dead.
3 minute also does not means it, but in the above case it would be better.

Alternatively, all service must be somehow convinced to ALLWAYS response within 50 sec (less than the proxy timeout), even if it is an 503. Not the haproxy's responsibility to kill a (potentially) valid in-progress request.