haproxy/doc
Willy Tarreau 826f3ab5e6 MINOR: stick-tables/counters: add http_fail_cnt and http_fail_rate data types
Historically we've been counting lots of client-triggered events in stick
tables to help detect misbehaving ones, but we've been missing the same on
the server side, and there's been repeated requests for being able to count
the server errors per URL in order to precisely monitor the quality of
service or even to avoid routing requests to certain dead services, which
is also called "circuit breaking" nowadays.

This commit introduces http_fail_cnt and http_fail_rate, which work like
http_err_cnt and http_err_rate in that they respectively count events and
their frequency, but they only consider server-side issues such as network
errors, unparsable and truncated responses, and 5xx status codes other
than 501 and 505 (since these ones are usually triggered by the client).
Note that retryable errors are purposely not accounted for, so that only
what the client really sees is considered.

With this it becomes very simple to put some protective measures in place
to perform a redirect or return an excuse page when the error rate goes
beyond a certain threshold for a given URL, and give more chances to the
server to recover from this condition. Typically it could look like this
to bypass a URL causing more than 10 requests per second:

  stick-table type string len 80 size 4k expire 1m store http_fail_rate(1m)
  http-request track-sc0 base       # track host+path, ignore query string
  http-request return status 503 content-type text/html \
      lf-file excuse.html if { sc0_http_fail_rate gt 10 }

A more advanced mechanism using gpt0 could even implement high/low rates
to disable/enable the service.

Reg-test converteers_ref_cnt_never_dec.vtc was updated to test it.
2021-02-10 12:27:01 +01:00
..
design-thoughts DOC: assorted typo fixes in the documentation 2020-03-09 14:45:58 +01:00
internals MAJOR: htx: Remove the EOM block type and use HTX_FL_EOM instead 2021-01-28 16:37:14 +01:00
lua-api DOC: assorted typo fixes in the documentation 2020-12-21 11:24:56 +01:00
51Degrees-device-detection.txt CLEANUP: 51d: move the 51d dummy lib to contrib/51d/src to match the real lib 2019-06-13 15:56:10 +02:00
acl.fig [DOC] add diagrams of queuing and future ACL design 2009-02-22 16:46:38 +01:00
architecture.txt DOC: Use gender neutral language 2020-07-26 22:35:43 +02:00
close-options.txt DOC: fix a few typos in the documentation 2018-11-18 22:23:15 +01:00
coding-style.txt DOC: assorted typo fixes in the documentation 2020-12-21 11:24:56 +01:00
configuration.txt MINOR: stick-tables/counters: add http_fail_cnt and http_fail_rate data types 2021-02-10 12:27:01 +01:00
cookie-options.txt DOC: fix a few typos in the documentation 2018-11-18 22:23:15 +01:00
DeviceAtlas-device-detection.txt DOC: fix typos 2019-05-25 07:34:24 +02:00
gpl.txt [LICENSE] licensing clarifications 2006-06-15 21:48:13 +02:00
haproxy.1 DOC: add description of pidfile in master-worker mode 2020-08-26 18:40:53 +02:00
intro.txt DOC: fix some spelling issues over multiple files 2021-01-08 14:53:47 +01:00
lgpl.txt [LICENSE] licensing clarifications 2006-06-15 21:48:13 +02:00
linux-syn-cookies.txt DOC: add doc/linux-syn-cookies.txt 2015-08-11 12:17:41 +02:00
lua.txt [RELEASE] Released version 2.3-dev2 2020-07-31 14:48:32 +02:00
management.txt MEDIUM: server: adding support for check_port in server state 2021-02-04 10:46:52 +01:00
netscaler-client-ip-insertion-protocol.txt DOC: fix typos 2019-05-25 07:34:24 +02:00
network-namespaces.txt MAJOR: namespace: add Linux network namespace support 2014-11-21 07:51:57 +01:00
peers-v2.0.txt DOC: Use gender neutral language 2020-07-26 22:35:43 +02:00
peers.txt DOC: peers: Update for dictionary cache entries for peers protocol. 2019-06-07 15:47:54 +02:00
proxy-protocol.txt DOC: Use gender neutral language 2020-07-26 22:35:43 +02:00
queuing.fig [DOC] add diagrams of queuing and future ACL design 2009-02-22 16:46:38 +01:00
regression-testing.txt DOC: assorted typo fixes in the documentation and Makefile 2020-03-06 10:49:55 +01:00
seamless_reload.txt CLEANUP: removed obsolete examples an move a few to better places 2019-06-15 21:25:06 +02:00
SOCKS4.protocol.txt MEDIUM: connection: Upstream SOCKS4 proxy support 2019-05-31 17:24:06 +02:00
SPOE.txt DOC: assorted typo fixes in the documentation 2020-06-26 11:27:10 +02:00
WURFL-device-detection.txt DOC: fix typos 2019-05-25 07:34:24 +02:00