mod_heartbeat.xml revision a99c5d4cc3cab6a62b04d52000dbc22ce1fa2d94
<?xml version="1.0"?>
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<modulesynopsis metafile="mod_heartbeat.xml.meta">
<name>mod_heartbeat</name>
<description>Sends messages with server status to frontend proxy</description>
<status>Experimental</status>
<sourcefile>mod_heartbeat</sourcefile>
<identifier>heartbeat_module</identifier>
<compatibility>Available in Apache 2.3 and later</compatibility>
<summary>
<p> <module>mod_heartbeat</module> sends multicast messages to a <module>mod_heartmonitor</module> listener
that advertises the servers current connection count. Usually, <module>mod_heartmonitor</module>
will be running on a proxy server with <module>mod_lbmethod_heartbeat</module> loaded, which allows
<directive module="mod_proxy">ProxyPass</directive> to use the "heartbeat" <em>lbmethod</em> inside
of <directive module="mod_proxy">ProxyPass</directive>.</p>
<p>
<module>mod_heartbeat</module> itself is loaded on the origin server(s) that serve requests
through the proxy server(s).
</p>
<note type="warning">
To use <module>mod_heartbeat</module>,
<module>mod_status</module> and <module>mod_watchdog</module>
must be either a static modules or, if a dynamic module, must
be loaded before <module>mod_heartbeat</module>.
</note>
</summary>
<section id="consuming">
<title>Consuming mod_heartbeat Output</title>
<p>
Every 1 second, this module generates a single multicast UDP
packet, containing the number of busy and idle workers. The
packet is a simple ASCII format, similar to GET query parameters
in HTTP.
</p>
<example><title>An Example Packet</title>
v=1&ready=75&busy=0
</example>
<p>
Consumers should handle new variables besides busy and ready,
separated by '&', being added in the future.
</p>
</section>
<directivesynopsis>
<name>HeartbeatAddress</name>
<description>Multicast address for heartbeat packets</description>
<syntax>HeartbeatAddress <var>addr:port</var></syntax>
<default>disabled</default>
<contextlist><context>server config</context></contextlist>
<usage>
<p>The <directive>HeartbeatAddress</directive> directive specifies the
multicast address to which <module>mod_heartbeat</module> will send
status information. This address will usually correspond to a configured
<directive module="mod_heartmonitor">HeartbeatListen</directive> on a
frontend proxy system.</p>
<highlight language="config">
HeartbeatAddress 239.0.0.1:27999
</highlight>
</usage>
</directivesynopsis>
</modulesynopsis>