stack/erp5: modernize haproxy config

* expect a minimum connection_count of 4, using 1 (or 2) seems to cause
balancing issues (test_balancer had several errors).

* set a timeout server, a bit more than the timeout client, to prevent
this warning:

    [WARNING]  (26864) : config : missing timeouts for proxy 'family_default'.
       | While not properly invalid, you will certainly encounter various problems
       | with such a configuration. To fix this, please ensure that all following
       | timeouts are set to a non-zero value: 'client', 'connect', 'server'.

* update health check directive to what the examples from
https://www.haproxy.com/blog/how-to-enable-health-checks-in-haproxy/

stack/erp5/buildout.hash.cfg

@@ -94,7 +94,7 @@ md5sum = b0751d3d12cfcc8934cb1027190f5e5e
 
 [template-haproxy-cfg]
 filename = haproxy.cfg.in
-md5sum = 1645ef8990ab2b50f91a4c02f0cf8882
+md5sum = cd084f1d57ad2c75f8f588b2a0f3f79f
 
 [template-rsyslogd-cfg]
 filename = rsyslogd.cfg.in

stack/erp5/haproxy.cfg.in

@@ -51,7 +51,7 @@
  #               None,  # timeout (in seconds) int | None
  #               [  # backends
  #                  '10.0.0.10:8001', # netloc str
- #                   1, # max_connection_count int
+ #                   5, # connection_count int
  #                   False, # is_web_dav bool
  #               ],
  #            ),
@@ -63,7 +63,7 @@
  #               None,  # timeout (in seconds) int | None
  #               [  # backends
  #                  '10.0.0.10:8003', # netloc str
- #                   1, # max_connection_count int
+ #                   10, # connection_count int
  #                   False, # is_web_dav bool
  #               ],
  #            ),
@@ -138,6 +138,7 @@ defaults
   timeout connect 10s
   timeout queue 60s
   timeout client 305s
+  timeout server 306s
 
   option http-server-close
 
@@ -193,10 +194,11 @@ listen family_{{ name }}
 {%   for address, connection_count, webdav in backend_list -%}
 {%     if webdav %}{% do has_webdav.append(None) %}{% endif -%}
 {%     set server_name = name ~ '-' ~ loop.index0 %}
-  server {{ server_name }} {{ address }} cookie {{ server_name }} check inter 3s rise 1 fall 2 maxqueue 5 maxconn {{ connection_count }}
+  server {{ server_name }} {{ address }} cookie {{ server_name }} check inter 3s rise 1 fall 2 maxqueue 5 maxconn {% if connection_count > 4 %} {{ connection_count }} {% else %} 4 {% endif %}
 {%-  endfor -%}
 {%-  if not has_webdav and server_check_path %}
-  option httpchk GET {{ server_check_path }}
+  option httpchk
+  http-check send meth GET uri {{ server_check_path }}
 {%-   endif %}
 
 {% endfor %}