diff options
| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:01:30 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:01:30 +0000 |
| commit | 6beeb1b708550be0d4a53b272283e17e5e35fe17 (patch) | |
| tree | 1ce8673d4aaa948e5554000101f46536a1e4cc29 /docs/manual/mod/mod_proxy_hcheck.html | |
| parent | Initial commit. (diff) | |
| download | apache2-upstream.tar.xz apache2-upstream.zip | |
Adding upstream version 2.4.57.upstream/2.4.57upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | docs/manual/mod/mod_proxy_hcheck.html | 9 | ||||
| -rw-r--r-- | docs/manual/mod/mod_proxy_hcheck.html.en | 282 | ||||
| -rw-r--r-- | docs/manual/mod/mod_proxy_hcheck.html.fr.utf8 | 314 |
3 files changed, 605 insertions, 0 deletions
diff --git a/docs/manual/mod/mod_proxy_hcheck.html b/docs/manual/mod/mod_proxy_hcheck.html new file mode 100644 index 0000000..e2a38bb --- /dev/null +++ b/docs/manual/mod/mod_proxy_hcheck.html @@ -0,0 +1,9 @@ +# GENERATED FROM XML -- DO NOT EDIT + +URI: mod_proxy_hcheck.html.en +Content-Language: en +Content-type: text/html; charset=UTF-8 + +URI: mod_proxy_hcheck.html.fr.utf8 +Content-Language: fr +Content-type: text/html; charset=UTF-8 diff --git a/docs/manual/mod/mod_proxy_hcheck.html.en b/docs/manual/mod/mod_proxy_hcheck.html.en new file mode 100644 index 0000000..d86ee12 --- /dev/null +++ b/docs/manual/mod/mod_proxy_hcheck.html.en @@ -0,0 +1,282 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mod_proxy_hcheck - Apache HTTP Server Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache Module mod_proxy_hcheck</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_proxy_hcheck.html" title="English"> en </a> | +<a href="../fr/mod/mod_proxy_hcheck.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Dynamic health check of Balancer members (workers) for +<code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></td></tr> +<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>proxy_hcheck_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_proxy_hcheck.c</td></tr> +<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.4.21 and later</td></tr></table> +<h3>Summary</h3> + + <p>This module provides for dynamic health checking of balancer + members (workers). This can be enabled on a worker-by-worker + basis. The health check is done independently of the + actual reverse proxy requests.</p> + + <p>This module <em>requires</em> the service of <code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code>.</p> + +<div class="note"><h3>Parameters</h3> + <p>The health check mechanism is enabled via the use of additional + <code class="directive"><a href="../mod/mod_proxy.html#balancermember">BalancerMember</a></code> parameters, which are configured + in the standard way via <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code>:</p> + + <p>A new BalancerMember <a href="mod_proxy.html#status_table">status</a> state (flag) + is defined via this module: "<code>C</code>". + When the worker is taken offline due to failures as determined by the health + check module, this flag is set, and can be seen (and modified) via the + <code>balancer-manager</code>.</p> + + <table> + <tr><th>Parameter</th> + <th>Default</th> + <th>Description</th></tr> + <tr><td>hcmethod</td> + <td>None</td> + <td>No dynamic health check performed. Choices are: + <table> + <tr><th>Method</th><th>Description</th><th>Note</th></tr> + <tr><td>None</td><td>No dynamic health checking done</td><td /></tr> + <tr><td>TCP</td><td>Check that a socket to the backend can be created: e.g. "are you up"</td><td /></tr> + <tr><td>OPTIONS</td><td>Send a <code>HTTP OPTIONS</code> request to the backend via <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>HEAD</td><td>Send a <code>HTTP HEAD</code> request to the backend via <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>GET</td><td>Send a <code>HTTP GET</code> request to the backend via <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>OPTIONS11</td><td>Send a <code>HTTP OPTIONS</code> request to the backend via <code>HTTP/1.1</code></td><td>*</td></tr> + <tr><td>HEAD11</td><td>Send a <code>HTTP HEAD</code> request to the backend via <code>HTTP/1.1</code></td><td>*</td></tr> + <tr><td>GET11</td><td>Send a <code>HTTP GET</code> request to the backend via <code>HTTP/1.1</code></td><td>*</td></tr> + + <tr><td colspan="3" /></tr> + <tr><td colspan="3">*: Unless <code>hcexpr</code> is used, a 2xx or 3xx HTTP status will be interpreted as <em>passing</em> the health check</td></tr> + </table> + </td></tr> + <tr><td>hcpasses</td> + <td>1</td> + <td>Number of successful health check tests before worker is re-enabled</td></tr> + <tr><td>hcfails</td> + <td>1</td> + <td>Number of failed health check tests before worker is disabled</td></tr> + <tr><td>hcinterval</td> + <td>30</td> + <td>Period of health checks in seconds (e.g. performed every 30 seconds)</td></tr> + <tr><td>hcuri</td> + <td> </td> + <td>Additional URI to be appended to the worker URL for the health check.</td></tr> + <tr><td>hctemplate</td> + <td> </td> + <td>Name of template, created via <code class="directive"><a href="#proxyhctemplate">ProxyHCTemplate</a></code>, + to use for setting health check parameters for this worker</td></tr> + <tr><td>hcexpr</td> + <td> </td> + <td>Name of expression, created via <code class="directive"><a href="#proxyhcexpr">ProxyHCExpr</a></code>, + used to check response headers for health.<br /> + <em>If not used, 2xx thru 3xx status codes imply success</em></td></tr> + </table> +</div> + +<div class="note"><h3>Compatibility:</h3> + <p><code>OPTIONS11</code>, <code>HEAD11</code> and <code>GET11</code> are + available in 2.4.55 and above.</p> +</div> + +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#examples">Usage examples</a></li> +</ul><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhcexpr">ProxyHCExpr</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhctemplate">ProxyHCTemplate</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhctpsize">ProxyHCTPsize</a></li> +</ul> +<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_proxy_hcheck">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_proxy_hcheck">Report a bug</a></li></ul><h3>See also</h3> +<ul class="seealso"> +<li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></li> +<li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="examples" id="examples">Usage examples</a></h2> + + + <p>The following example shows how one might configured health checking + for various backend servers:</p> + + + <pre class="prettyprint lang-config">ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/} +ProxyHCExpr gdown {%{REQUEST_STATUS} =~ /^[5]/} +ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/} + +<Proxy balancer://foo> + BalancerMember http://www.example.com/ hcmethod=GET hcexpr=in_maint hcuri=/status.php + BalancerMember http://www2.example.com/ hcmethod=HEAD hcexpr=ok234 hcinterval=10 + BalancerMember http://www3.example.com/ hcmethod=TCP hcinterval=5 hcpasses=2 hcfails=3 + BalancerMember http://www4.example.com/ +</Proxy> + +ProxyPass "/" "balancer://foo" +ProxyPassReverse "/" "balancer://foo"</pre> + + +<p>In this scenario, <code>http://www.example.com/</code> is health checked by sending a <code>GET /status.php</code> +request to that server and seeing that the returned page does not include the string <em>Under maintenance</em>. If +it does, that server is put in health-check fail mode, and disabled. This dynamic check is performed +every 30 seconds, which is the default.</p> + +<p><code>http://www2.example.com/</code> is checked by sending a simple <code>HEAD</code> request every +10 seconds and making sure that the response status is 2xx, 3xx or 4xx. <code>http://www3.example.com/</code> is checked +every 5 seconds by simply ensuring that the socket to that server is up. If the backend is marked as +"down" and it passes 2 health check, it will be re-enabled and added back into the load balancer. +It takes 3 back-to-back health check failures to disable the server and move it out +of rotation. Finally, <code>http://www4.example.com/</code> is +not dynamically checked at all.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyHCExpr" id="ProxyHCExpr">ProxyHCExpr</a> <a name="proxyhcexpr" id="proxyhcexpr">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Creates a named condition expression to use to determine health of the backend based on its response</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyHCExpr <em>name</em> {<em>ap_expr expression</em>}</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>The <code class="directive">ProxyHCExpr</code> directive allows + for creating a named condition expression that checks the response + headers of the backend server to determine its health. This named + condition can then be assigned to balancer members via the <code>hcexpr</code> + parameter.</p> + + <div class="example"><h3>ProxyHCExpr: Allow for 2xx/3xx/4xx as passing</h3><pre class="prettyprint lang-config">ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/} +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www2.example.com/ hcmethod=HEAD hcexpr=ok234 hcinterval=10 +</Proxy></pre> +</div> + + <div class="note"> + The <a href="../expr.html">expression</a> can use curly-parens ("{}") as + quoting deliminators in addition to normal quotes. + </div> + + <p>If using a health check method (eg: <code>GET</code>) which results in a response + body, that body itself can be checked via <code>ap_expr</code> using the <code>hc()</code> + expression function, which is unique to this module.</p> + + <p>In the following example, we send the backend a <code>GET</code> request + and if the response body contains the phrase <em>Under maintenance</em>, + we want to disable the backend.</p> + + <div class="example"><h3>ProxyHCExpr: Checking response body</h3><pre class="prettyprint lang-config">ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/} +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www.example.com/ hcexpr=in_maint hcmethod=get hcuri=/status.php +</Proxy></pre> +</div> + + <p><em>NOTE:</em> Since response body can quite large, it is best if used against specific status pages.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyHCTemplate" id="ProxyHCTemplate">ProxyHCTemplate</a> <a name="proxyhctemplate" id="proxyhctemplate">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Creates a named template for setting various health check parameters</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyHCTemplate <em>name</em> <em>parameter</em>=<em>setting</em> [...]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>The <code class="directive">ProxyHCTemplate</code> directive allows + for creating a named set (template) of health check parameters + that can then be assigned to balancer members via the <code>hctemplate</code> + parameter.</p> + + <div class="example"><h3>ProxyHCTemplate</h3><pre class="prettyprint lang-config">ProxyHCTemplate tcp5 hcmethod=tcp hcinterval=5 +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www2.example.com/ hctemplate=tcp5 +</Proxy></pre> +</div> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyHCTPsize" id="ProxyHCTPsize">ProxyHCTPsize</a> <a name="proxyhctpsize" id="proxyhctpsize">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the total server-wide size of the threadpool used for the health check workers</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyHCTPsize <em>size</em></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyHCTPsize 16</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>If Apache httpd and APR are built with thread support, the health check + module will offload the work of the actual checking to a threadpool + associated with the Watchdog process, allowing for parallel checks. + The <code class="directive">ProxyHCTPsize</code> directive + determines the size of this threadpool. If set to <code>0</code>, no threadpool + is used at all, resulting in serialized health checks.</p> + + <div class="example"><h3>ProxyHCTPsize</h3><pre class="prettyprint lang-config">ProxyHCTPsize 32</pre> +</div> + + +</div> +</div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_proxy_hcheck.html" title="English"> en </a> | +<a href="../fr/mod/mod_proxy_hcheck.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/mod_proxy_hcheck.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2023 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
\ No newline at end of file diff --git a/docs/manual/mod/mod_proxy_hcheck.html.fr.utf8 b/docs/manual/mod/mod_proxy_hcheck.html.fr.utf8 new file mode 100644 index 0000000..77e717a --- /dev/null +++ b/docs/manual/mod/mod_proxy_hcheck.html.fr.utf8 @@ -0,0 +1,314 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="fr" xml:lang="fr"><head> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mod_proxy_hcheck - Serveur HTTP Apache Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossaire</a> | <a href="../sitemap.html">Plan du site</a></p> +<p class="apache">Serveur HTTP Apache Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">Serveur HTTP</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Module Apache mod_proxy_hcheck</h1> +<div class="toplang"> +<p><span>Langues Disponibles: </span><a href="../en/mod/mod_proxy_hcheck.html" hreflang="en" rel="alternate" title="English"> en </a> | +<a href="../fr/mod/mod_proxy_hcheck.html" title="Français"> fr </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Check up dynamique des membres du groupe de répartition de charge +(équipiers) pour <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></td></tr> +<tr><th><a href="module-dict.html#Status">Statut:</a></th><td>Extension</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Identificateur de Module:</a></th><td>proxy_hcheck_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Fichier Source:</a></th><td>mod_proxy_hcheck.c</td></tr> +<tr><th><a href="module-dict.html#Compatibility">Compatibilité:</a></th><td>Disponible à partir de la version 2.4.21 du serveur HTTP Apache</td></tr></table> +<h3>Sommaire</h3> + + <p>Ce module permet d'effectuer un check up dynamique des membres du groupe + de répartition de charge (équipiers). Ce check up peut être activé pour un + ou plusieurs équipiers et il est indépendant des requêtes de mandataire + inverse proprement dites.</p> + + <p>Pour fonctionner, ce module <em>nécessite</em> le chargement préalable de + <code class="module"><a href="../mod/mod_watchdog.html">mod_watchdog</a></code>.</p> + +<div class="note"><h3>Paramètres</h3> + <p>Le mécanisme de check up est activé via l'utilisation de paramètres + supplémentaires de la directive <code class="directive"><a href="../mod/mod_proxy.html#balancermember">BalancerMember</a></code> configurés de manière standard + via la directive <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> :</p> + + <p>Ce module définit un nouveau drapeau d'état <a href="mod_proxy.html#status_table">status</a> pour BalancerMember : + "<code>C</code>". Lorsque l'équipier est mis hors service suite à un + disfonctionnement déterminé par le module de check up, ce drapeau est activé + et peut être lu (et modifié) via le <code>balancer-manager</code>.</p> + + <table> + <tr><th>Paramètre</th> + <th>Défaut</th> + <th>Description</th></tr> + <tr><td>hcmethod</td> + <td>None</td> + <td>Aucun check up dynamique n'est effectué. Les choix possibles sont : + <table> + <tr><th>Method</th><th>Description</th><th>Note</th></tr> + <tr><td>None</td><td>Aucun check up dynamique effectué</td><td /></tr> + <tr><td>TCP</td><td>Vérifie qu'un socket vers le serveur + d'arrière-plan peut être créé ; par exemple "es-tu en + état de fonctionner"</td><td /></tr> + <tr><td>OPTIONS</td><td>Envoie une requête <code>HTTP + OPTIONS</code> au serveur d'arrière-plan via + <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>HEAD</td><td>Envoie une requête <code>HTTP + HEAD</code> au serveur d'arrière-plan via + <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>GET</td><td>Envoie une requête <code>HTTP + GET</code> au serveur d'arrière-plan via + <code>HTTP/1.0</code></td><td>*</td></tr> + <tr><td>OPTIONS11</td><td>Envoie une requête <code>HTTP + OPTIONS</code> au serveur d'arrière-plan via + <code>HTTP/1.1</code></td><td>*</td></tr> + <tr><td>HEAD11</td><td>Envoie une requête <code>HTTP + HEAD</code> au serveur d'arrière-plan via + <code>HTTP/1.1</code></td><td>*</td></tr> + <tr><td>GET11</td><td>Envoie une requête <code>HTTP + GET</code> au serveur d'arrière-plan via + <code>HTTP/1.1</code></td><td>*</td></tr> + + <tr><td colspan="3" /></tr> + <tr><td colspan="3">*: si hcexpr n'est pas + utilisé, un retour HTTP 2xx ou 3xx sera + interprété comme un passage avec succès du check + up.</td></tr> + </table> + </td></tr> + <tr><td>hcpasses</td> + <td>1</td> + <td>Nombre de check up à passer avec succès avant de remettre en service + l'équipier</td></tr> + <tr><td>hcfails</td> + <td>1</td> + <td>Nombre de check up échoués avant mettre hors service l'équipier</td></tr> + <tr><td>hcinterval</td> + <td>30</td> + <td>Intervalle entre deux check up en secondes (par défaut effectué + toutes les 30 secondes)</td></tr> + <tr><td>hcuri</td> + <td> </td> + <td>URI supplémentaire à ajouter à l'URL de l'équipier pour le check up.</td></tr> + <tr><td>hctemplate</td> + <td> </td> + <td>Nom du modèle créé via <code class="directive"><a href="#proxyhctemplate">ProxyHCTemplate</a></code> à + utiliser pour définir les paramètres de check up de cet équipier</td></tr> + <tr><td>hcexpr</td> + <td> </td> + <td>Nom de l'expression créée via <code class="directive"><a href="#proxyhcexpr">ProxyHCExpr</a></code> + utilisée pour analyser les en-têtes de la réponse du check up.<br /> + <em>Si ce paramètre est absent, un état HTTP de 2xx à 3xx est + interprété comme un check up réussi.</em></td></tr> + </table> +</div> + +<div class="note"><h3>Compatibilité :</h3> + <p><code>OPTIONS11</code>, <code>HEAD11</code> et <code>GET11</code> sont + disponibles à partir de la version 2.4.55 du serveur HTTP Apache.</p> +</div> + +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Sujets</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#examples">Exemples d'utilisation</a></li> +</ul><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhcexpr">ProxyHCExpr</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhctemplate">ProxyHCTemplate</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyhctpsize">ProxyHCTPsize</a></li> +</ul> +<h3>Traitement des bugs</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">Journal des modifications de httpd</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_proxy_hcheck">Problèmes connus</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_proxy_hcheck">Signaler un bug</a></li></ul><h3>Voir aussi</h3> +<ul class="seealso"> +<li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></li> +<li><a href="#comments_section">Commentaires</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="examples" id="examples">Exemples d'utilisation</a></h2> + + + <p>L'exemple suivant montre comment configurer le check up pour différents + serveurs d'arrière-plan :</p> + + + <pre class="prettyprint lang-config">ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/} +ProxyHCExpr gdown {%{REQUEST_STATUS} =~ /^[5]/} +ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/} + +<Proxy balancer://foo> + BalancerMember http://www.example.com/ hcmethod=GET hcexpr=in_maint hcuri=/status.php + BalancerMember http://www2.example.com/ hcmethod=HEAD hcexpr=ok234 hcinterval=10 + BalancerMember http://www3.example.com/ hcmethod=TCP hcinterval=5 hcpasses=2 hcfails=3 + BalancerMember http://www4.example.com/ +</Proxy> + +ProxyPass "/" "balancer://foo" +ProxyPassReverse "/" "balancer://foo"</pre> + + +<p>Dans ce scénario, on teste l'équipier <code>http://www.example.com/</code> en lui +envoyant une requête <code>GET /status.php</code> et en regardant si la réponse +contient la chaîne <em>Under maintenance</em>. Si c'est le cas, le check up est +considéré comme ayant échoué et l'équipier est mis hors service. Ce check up +dynamique est effectué toutes les 30 secondes, ce qui correspond à la valeur par +défaut.</p> + +<p>On teste l'équipier <code>http://www2.example.com/</code> en lui envoyant +simplement une requête <code>HEAD</code> toutes les 10 secondes et en vérifiant +que la réponse HTTP est bien un code d'état de 2xx, 3xx ou 4xx. On teste +l'équipier <code>http://www3.example.com/</code> en vérifiant simplement toutes +les 5 secondes que le socket vers ce serveur est bien opérationnel. Si ce +serveur est marqué "hors service", il lui faudra 2 check up réussis pour être +réactivé et participer à nouveau à la répartition de charge. Si à ce moment-là +il échoue à 3 check up successifs, il sera à nouveau mis hors service. Enfin, +l'équipier <code>http://www4.example.com/</code> ne fait l'objet d'aucun check +up.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="proxyhcexpr" id="proxyhcexpr">Directive</a> <a name="ProxyHCExpr" id="ProxyHCExpr">ProxyHCExpr</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Crée et nomme une expression conditionnelle à utiliser pour +déterminer la santé d'un serveur d'arrière-plan en fonction de sa valeur</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntaxe:</a></th><td><code>ProxyHCExpr <em>name</em> {<em>ap_expr expression</em>}</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Contexte:</a></th><td>configuration globale, serveur virtuel</td></tr> +<tr><th><a href="directive-dict.html#Status">Statut:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>La directive <code class="directive">ProxyHCExpr</code> permet de créer et nommer + une expression conditionnelle dont la valeur calculée en fonction des + en-têtes de la réponse du serveur d'arrière-plan permettra d'évaluer la + santé de ce dernier. Cette expression nommée peut alors être assignée aux + serveurs d'arrière-plan via le paramètre <code>hcexpr</code>.</p> + + <div class="example"><h3>ProxyHCExpr: interprète les réponses 2xx/3xx/4xx comme des + check up réussis</h3><pre class="prettyprint lang-config">ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/} +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www2.example.com/ hcmethod=HEAD hcexpr=ok234 hcinterval=10 +</Proxy></pre> +</div> + + <div class="note"> + L'<a href="../expr.html">expression</a> peut utiliser des accolades ("{}") + comme délimiteurs en plus des guillemets normaux. + </div> + + <p>Si l'on utilise une méthode de check up (par exemple <code>GET</code>) + qui génère un corps de réponse, ce corps peut lui-même être ausculté via + <code>ap_expr</code> en utilisant la fonction associée aux expressions + <code>hc()</code> spécifique à ce module.</p> + + <p>Dans l'exemple suivant, on envoie une requête <code>GET</code> au serveur + d'arrière-plan, et si le corps de la réponse contient la chaîne <em>Under + maintenance</em>, ce serveur d'arrière-plan est mis hors service.</p> + + <div class="example"><h3>ProxyHCExpr: auscultation du corps de la réponse</h3><pre class="prettyprint lang-config">ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/} +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www.example.com/ hcexpr=in_maint hcmethod=get hcuri=/status.php +</Proxy></pre> +</div> + + <p><em>NOTE:</em> Comme le corps de la réponse peut être assez grand, il est + recommandé de privilégier un check up basé sur les codes d'état.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="proxyhctemplate" id="proxyhctemplate">Directive</a> <a name="ProxyHCTemplate" id="ProxyHCTemplate">ProxyHCTemplate</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Crée et nomme un modèle permettant de définir différents +paramètres de check up</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntaxe:</a></th><td><code>ProxyHCTemplate <em>name</em> <em>parameter</em>=<em>setting</em> [...]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Contexte:</a></th><td>configuration globale, serveur virtuel</td></tr> +<tr><th><a href="directive-dict.html#Status">Statut:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>La directive <code class="directive">ProxyHCTemplate</code> permet de créer et + nommer un modèle de paramètres de check up qui peut alors être assigné aux + équipiers via le paramètre <code>hctemplate</code>.</p> + + <div class="example"><h3>ProxyHCTemplate</h3><pre class="prettyprint lang-config">ProxyHCTemplate tcp5 hcmethod=tcp hcinterval=5 +ProxyPass "/apps" "balancer://foo" + +<Proxy balancer://foo> + BalancerMember http://www2.example.com/ hctemplate=tcp5 +</Proxy></pre> +</div> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="proxyhctpsize" id="proxyhctpsize">Directive</a> <a name="ProxyHCTPsize" id="ProxyHCTPsize">ProxyHCTPsize</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Définit la taille totale, pour l'ensemble du +serveur, du jeu de threads utilisé pour le check up des +équipiers</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntaxe:</a></th><td><code>ProxyHCTPsize <em>size</em></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Défaut:</a></th><td><code>ProxyHCTPsize 16</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Contexte:</a></th><td>configuration globale</td></tr> +<tr><th><a href="directive-dict.html#Status">Statut:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy_hcheck</td></tr> +</table> + <p>Si Apache httpd et APR ont été compilés avec le support des threads, le + module de check up peut confier ce travail à un jeu de threads associé au + processus Watchdog, ce qui permet l'exécution des check up en parallèle. La + directive <code class="directive">ProxyHCTPsize</code> permet de déterminer la + taille de ce jeu de threads. Une valeur de <code>0</code> signifie qu'aucun + jeu de threads ne sera utilisé, et le check up des différents équipiers sera + alors effectué séquentiellement.</p> + + <div class="example"><h3>ProxyHCTPsize</h3><pre class="prettyprint lang-config">ProxyHCTPsize 32</pre> +</div> + + +</div> +</div> +<div class="bottomlang"> +<p><span>Langues Disponibles: </span><a href="../en/mod/mod_proxy_hcheck.html" hreflang="en" rel="alternate" title="English"> en </a> | +<a href="../fr/mod/mod_proxy_hcheck.html" title="Français"> fr </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Commentaires</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. 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