[DOC] document "nbsrv" and "monitor fail"
diff --git a/doc/configuration.txt b/doc/configuration.txt
index d37008b..d8d242a 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -261,6 +261,7 @@
log X X X X
maxconn X X X -
mode X X X X
+monitor fail - X X -
monitor-net X X X -
monitor-uri X X X -
option abortonclose X - X X
@@ -605,6 +606,13 @@
contain more than one of certain headers. See "hdr" for more information on
header matching.
+nbsrv <integer>
+nbsrv(backend) <integer>
+ Returns true when the number of usable servers of either the current backend
+ or the named backend matches the values or ranges specified. This is used to
+ switch to an alternate backend when the number of servers is too low to
+ to handle some load. It is useful to report a failure when combined with
+ "monitor fail".
2.1.6) Pre-defined ACLs
-----------------------
@@ -676,7 +684,31 @@
See below for the detailed help on the "block" and "use_backend" keywords.
-2.2) Options
+2.2) Instance-specific keywords and statements
+----------------------------------------------
+
+monitor fail [if | unless] <condition>
+ [ supported in: frontend, listen ]
+
+ This statement adds a condition which can force the response to a monitor
+ request to report a failure. By default, when an external component queries
+ the URI dedicated to monitoring, a 200 response is returned. When one of the
+ conditions above is met, haproxy will return 503 instead of 200. This is
+ very useful to report a site failure to an external component which may base
+ routing advertisements between multiple sites on the availability reported by
+ haproxy. In this case, one would rely on an ACL involving the "nbsrv"
+ criterion.
+
+ Example:
+
+ frontend www
+ acl site_dead nbsrv(dynamic) lt 2
+ acl site_dead nbsrv(static) lt 2
+ monitor-uri /site_alive
+ monitor fail if site_dead
+
+
+2.3) Options
------------
A handful of options affect the way the load balancing is performed or reaction
@@ -703,7 +735,7 @@
it is not enabled by default, as it has small performance impact (~0.5%).
-2.3) Server options
+2.4) Server options
-------------------
slowstart <start_time_in_ms>