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2 | 2 | <html lang="en"> |
3 | 3 | <head> |
4 | 4 | <meta charset="utf-8" /> |
5 | | - <title>HAProxy version 3.1.7-1 - Configuration Manual</title> |
| 5 | + <title>HAProxy version 3.1.7-44 - Configuration Manual</title> |
6 | 6 | <link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" /> |
7 | 7 | <link href="https://raw.githubusercontent.com/thomaspark/bootswatch/v3.3.7/cerulean/bootstrap.min.css" rel="stylesheet" /> |
8 | 8 | <link href="../css/page.css?0.4.2-15" rel="stylesheet" /> |
|
4430 | 4430 | You can use <strong>left</strong> and <strong>right</strong> arrow keys to navigate between chapters.<br> |
4431 | 4431 | </p> |
4432 | 4432 | <p class="text-right"> |
4433 | | - <small>Converted with <a href="https://github.com/cbonte/haproxy-dconv">haproxy-dconv</a> v<b>0.4.2-15</b> on <b>2025/04/17</b></small> |
| 4433 | + <small>Converted with <a href="https://github.com/cbonte/haproxy-dconv">haproxy-dconv</a> v<b>0.4.2-15</b> on <b>2025/05/15</b></small> |
4434 | 4434 | </p> |
4435 | 4435 | </div> |
4436 | 4436 | <!-- /.sidebar --> |
|
4441 | 4441 | <div class="text-center"> |
4442 | 4442 | <h1><a href="http://www.haproxy.org/" title="HAProxy"><img src="../img/HAProxyCommunityEdition_60px.png?0.4.2-15" /></a></h1> |
4443 | 4443 | <h2>Configuration Manual</h2> |
4444 | | - <p><strong>version 3.1.7-1</strong></p> |
| 4444 | + <p><strong>version 3.1.7-44</strong></p> |
4445 | 4445 | <p> |
4446 | 4446 | 2025/04/17<br> |
4447 | 4447 |
|
@@ -10199,7 +10199,7 @@ <h2 id="chapter-3.9" data-target="3.9"><small><a class="small" href="#3.9">3.9.< |
10199 | 10199 |
|
10200 | 10200 | ring myring |
10201 | 10201 | description "My local buffer" |
10202 | | - format rfc3164 |
| 10202 | + format rfc5424 |
10203 | 10203 | maxlen 1200 |
10204 | 10204 | size 32764 |
10205 | 10205 | timeout connect 5s |
@@ -22075,15 +22075,20 @@ <h2 id="chapter-5.2" data-target="5.2"><small><a class="small" href="#5.2">5.2.< |
22075 | 22075 | instances on the fly. This option defaults to "last,libc" indicating that the |
22076 | 22076 | previous address found in the state file (if any) is used first, otherwise |
22077 | 22077 | the libc's resolver is used. This ensures continued compatibility with the |
22078 | | -historic behavior. |
22079 | | -</pre><div class="separator"> |
22080 | | -<span class="label label-success">Example:</span> |
22081 | | -<pre class="prettyprint"> |
22082 | | -<code>defaults |
22083 | | - <span class="comment"># never fail on address resolution</span> |
22084 | | - default-server init-addr last,libc,none |
22085 | | -</code></pre> |
22086 | | -</div><a class="anchor" name="inter"></a><a class="anchor" name="5-inter"></a><a class="anchor" name="5.2-inter"></a><a class="anchor" name="inter (Bind and server options)"></a><a class="anchor" name="inter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="inter"></a><a href="#5.2-inter">inter</a></b> <span style="color: #080"><delay></span></div><a class="anchor" name="fastinter"></a><a class="anchor" name="5-fastinter"></a><a class="anchor" name="5.2-fastinter"></a><a class="anchor" name="fastinter (Bind and server options)"></a><a class="anchor" name="fastinter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="fastinter"></a><a href="#5.2-fastinter">fastinter</a></b> <span style="color: #080"><delay></span></div><a class="anchor" name="downinter"></a><a class="anchor" name="5-downinter"></a><a class="anchor" name="5.2-downinter"></a><a class="anchor" name="downinter (Bind and server options)"></a><a class="anchor" name="downinter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="downinter"></a><a href="#5.2-downinter">downinter</a></b> <span style="color: #080"><delay></span></div><pre class="text">May be used in the following contexts: tcp, http, log |
| 22078 | +historic behavior. When using internal resolvers, it is generally recommended |
| 22079 | +to either disable libc-based resolution, or make it explicit (see <a href="#5.3">section 5.3</a> |
| 22080 | +for more details). |
| 22081 | + |
| 22082 | +Example 1: |
| 22083 | + defaults |
| 22084 | + # never fail on address resolution |
| 22085 | + default-server init-addr last,libc,none |
| 22086 | + |
| 22087 | +Example 2: |
| 22088 | + defaults |
| 22089 | + # disable libc resolution in combination with resolvers |
| 22090 | + default-server init-addr last,none |
| 22091 | +</pre><a class="anchor" name="inter"></a><a class="anchor" name="5-inter"></a><a class="anchor" name="5.2-inter"></a><a class="anchor" name="inter (Bind and server options)"></a><a class="anchor" name="inter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="inter"></a><a href="#5.2-inter">inter</a></b> <span style="color: #080"><delay></span></div><a class="anchor" name="fastinter"></a><a class="anchor" name="5-fastinter"></a><a class="anchor" name="5.2-fastinter"></a><a class="anchor" name="fastinter (Bind and server options)"></a><a class="anchor" name="fastinter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="fastinter"></a><a href="#5.2-fastinter">fastinter</a></b> <span style="color: #080"><delay></span></div><a class="anchor" name="downinter"></a><a class="anchor" name="5-downinter"></a><a class="anchor" name="5.2-downinter"></a><a class="anchor" name="downinter (Bind and server options)"></a><a class="anchor" name="downinter (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="downinter"></a><a href="#5.2-downinter">downinter</a></b> <span style="color: #080"><delay></span></div><pre class="text">May be used in the following contexts: tcp, http, log |
22087 | 22092 |
|
22088 | 22093 | The "<a href="#inter">inter</a>" parameter sets the interval between two consecutive health checks |
22089 | 22094 | to <delay> milliseconds. If left unspecified, the delay defaults to 2000 ms. |
@@ -22624,13 +22629,16 @@ <h2 id="chapter-5.2" data-target="5.2"><small><a class="small" href="#5.2">5.2.< |
22624 | 22629 | </div><a class="anchor" name="resolvers"></a><a class="anchor" name="5-resolvers"></a><a class="anchor" name="5.2-resolvers"></a><a class="anchor" name="resolvers (Bind and server options)"></a><a class="anchor" name="resolvers (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="resolvers"></a><a href="#5.2-resolvers">resolvers</a></b> <span style="color: #080"><id></span></div><pre class="text">May be used in the following contexts: tcp, http, log |
22625 | 22630 |
|
22626 | 22631 | Points to an existing "<span class="dropdown"><a class="dropdown-toggle" data-toggle="dropdown" href="#">resolvers<span class="caret"></span></a><ul class="dropdown-menu"><li class="dropdown-header">This keyword is available in sections :</li><li><a href="#resolvers%20%28Server%20and%20default-server%20options%29">Server and default-server options</a></li><li><a href="#resolvers%20%28The%20resolvers%20section%29">The resolvers section</a></li></ul></span>" section to resolve current server's |
22627 | | -hostname. |
| 22632 | +hostname. It is often recommended to disable libc-based resolution when using |
| 22633 | +resolvers, though exceptions exist (see <a href="#5.3.1">section 5.3.1</a>). In any case it is a |
| 22634 | +good practice to explicitly specify "<a href="#init-addr">init-addr</a>" when using resolvers in order |
| 22635 | +not to overlook this element. |
22628 | 22636 | </pre><div class="separator"> |
22629 | 22637 | <span class="label label-success">Example:</span> |
22630 | 22638 | <pre class="prettyprint"> |
22631 | | -<code>server s1 app1.domain.com:80 check resolvers mydns |
| 22639 | +<code>server s1 app1.domain.com:80 init-addr last,none check resolvers mydns |
22632 | 22640 | </code></pre> |
22633 | | -</div><pre class="text">See also <a href="#5.3">section 5.3</a> |
| 22641 | +</div><pre class="text">See also <a href="#5.3">section 5.3</a> for implementation details and traps to be aware of. |
22634 | 22642 | </pre><a class="anchor" name="send-proxy"></a><a class="anchor" name="5-send-proxy"></a><a class="anchor" name="5.2-send-proxy"></a><a class="anchor" name="send-proxy (Bind and server options)"></a><a class="anchor" name="send-proxy (Server and default-server options)"></a><div class="keyword"><b><a class="anchor" name="send-proxy"></a><a href="#5.2-send-proxy">send-proxy</a></b></div><pre class="text">May be used in the following contexts: tcp, http |
22635 | 22643 |
|
22636 | 22644 | The "<a href="#send-proxy">send-proxy</a>" parameter enforces use of the PROXY protocol over any |
@@ -22953,10 +22961,13 @@ <h2 id="chapter-5.3" data-target="5.3"><small><a class="small" href="#5.3">5.3.< |
22953 | 22961 | This is not sufficient in some cases, such as in Amazon where a server's IP |
22954 | 22962 | can change after a reboot or an ELB Virtual IP can change based on current |
22955 | 22963 | workload. |
| 22964 | + |
22956 | 22965 | This chapter describes how HAProxy can be configured to process server's name |
22957 | 22966 | resolution at run time. |
22958 | | -Whether run time server name resolution has been enable or not, HAProxy will |
22959 | | -carry on doing the first resolution when parsing the configuration. |
| 22967 | + |
| 22968 | +Whether run time server name resolution has been enable or not, by default |
| 22969 | +HAProxy will do the first resolution at startup during configuration parsing |
| 22970 | +via libc unless disabled by the "<a href="#init-addr">init-addr</a>" parameter. |
22960 | 22971 | </pre></div> |
22961 | 22972 | <a class="anchor" id="5.3.1" name="5.3.1"></a> |
22962 | 22973 | <h3 id="chapter-5.3.1" data-target="5.3.1"><small><a class="small" href="#5.3.1">5.3.1.</a></small> Global overview</h3> |
@@ -22988,6 +22999,17 @@ <h3 id="chapter-5.3.1" data-target="5.3.1"><small><a class="small" href="#5.3.1" |
22988 | 22999 |
|
22989 | 23000 | - a resolution is considered as invalid (NX, timeout, refused), when all the |
22990 | 23001 | servers return an error. |
| 23002 | + |
| 23003 | + - The DNS client implemented in HAProxy is very basic and will not understand |
| 23004 | + the vast number of options and advanced setups that an operating system's |
| 23005 | + resolver can deal with. As such, except for really trivial setups where a |
| 23006 | + server known by its FQDN only has exactly one IP address at a time and |
| 23007 | + might occasionally renew it (e.g. a reboot), it is highly recommended to |
| 23008 | + avoid mixing libc-based init-time resolution with DNS-based runtime |
| 23009 | + resolution, as such setups are known to cause failures upon address |
| 23010 | + renewal. As a conclusion, unless you know exactly what you are doing, you |
| 23011 | + should always exclude "libc" from "<a href="#init-addr">init-addr</a>" when using "<span class="dropdown"><a class="dropdown-toggle" data-toggle="dropdown" href="#">resolvers<span class="caret"></span></a><ul class="dropdown-menu"><li class="dropdown-header">This keyword is available in sections :</li><li><a href="#resolvers%20%28Server%20and%20default-server%20options%29">Server and default-server options</a></li><li><a href="#resolvers%20%28The%20resolvers%20section%29">The resolvers section</a></li></ul></span>" on a |
| 23012 | + server line. |
22991 | 23013 | </pre></div> |
22992 | 23014 | <a class="anchor" id="5.3.2" name="5.3.2"></a> |
22993 | 23015 | <h3 id="chapter-5.3.2" data-target="5.3.2"><small><a class="small" href="#5.3.2">5.3.2.</a></small> The resolvers section</h3> |
@@ -23114,6 +23136,8 @@ <h3 id="chapter-5.3.2" data-target="5.3.2"><small><a class="small" href="#5.3.2" |
23114 | 23136 | valid status from the DNS server. |
23115 | 23137 |
|
23116 | 23138 | A separate behavior exists for "hold valid" and "hold obsolete". |
| 23139 | + |
| 23140 | +Default value is 10s for "valid", 0s for "obsolete" and 30s for others. |
23117 | 23141 | </pre><a class="anchor" name="resolve_retries"></a><a class="anchor" name="5-resolve_retries"></a><a class="anchor" name="5.3.2-resolve_retries"></a><a class="anchor" name="resolve_retries (Bind and server options)"></a><a class="anchor" name="resolve_retries (The resolvers section)"></a><div class="keyword"><b><a class="anchor" name="resolve_retries"></a><a href="#5.3.2-resolve_retries">resolve_retries</a></b> <span style="color: #080"><nb></span></div><pre class="text">Defines the number <nb> of queries to send to resolve a server name before |
23118 | 23142 | giving up. |
23119 | 23143 | Default value: 3 |
@@ -31759,7 +31783,7 @@ <h2 id="chapter-11.3" data-target="11.3"><small><a class="small" href="#11.3">11 |
31759 | 31783 | <br> |
31760 | 31784 | <hr> |
31761 | 31785 | <div class="text-right"> |
31762 | | - HAProxy 3.1.7-1 – Configuration Manual<br> |
| 31786 | + HAProxy 3.1.7-44 – Configuration Manual<br> |
31763 | 31787 | <small>, 2025/04/17</small> |
31764 | 31788 | </div> |
31765 | 31789 | </div> |
|
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