docs/manual/mod/mod_heartmonitor.xml

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<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
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<modulesynopsis metafile="mod_heartmonitor.xml.meta">

<name>mod_heartmonitor</name>
<description>Centralized monitor for mod_heartbeat origin servers</description>
<status>Experimental</status>
<sourcefile>mod_heartmonitor.c</sourcefile>
<identifier>heartmonitor_module</identifier>
<compatibility>Available in Apache 2.3 and later</compatibility>

<summary>
<p>
<module>mod_heartmonitor</module> listens for server status messages generated
by <module>mod_heartbeat</module> enabled origin servers and makes their status
available to <module>mod_lbmethod_heartbeat</module>. This allows
<directive module="mod_proxy">ProxyPass</directive> to use the "heartbeat"
<em>lbmethod</em> inside of <directive module="mod_proxy">ProxyPass</directive>.
</p>

<p>This module uses the services of <module>mod_slotmem_shm</module> when
available instead of flat-file storage.  No configuration is required to
use <module>mod_slotmem_shm</module>.</p>

    <note type="warning">
        To use <module>mod_heartmonitor</module>,
        <module>mod_status</module> and <module>mod_watchdog</module>
        must be either a static modules or, if a dynamic module, it must
        be loaded before <module>mod_heartmonitor</module>.
    </note>

</summary>

<directivesynopsis>
<name>HeartbeatListen</name>
<description>multicast address to listen for incoming heartbeat requests </description>
<syntax>HeartbeatListen <var>addr:port</var></syntax>
<default>disabled</default>
<contextlist><context>server config</context></contextlist>

<usage>
    <p>The <directive>HeartbeatListen</directive> directive specifies the
    multicast address on which the server will listen for status information from
    <module>mod_heartbeat</module>-enabled servers.  This
    address will usually correspond to a configured  <directive
    module="mod_heartbeat">HeartbeatAddress</directive> on an origin server.
    </p>

    <highlight language="config">
    HeartbeatListen 239.0.0.1:27999
    </highlight>

    <p> This module is inactive until this directive is used.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>HeartbeatStorage</name>
<description>Path to store heartbeat data when using flat-file storage</description>
<syntax>HeartbeatStorage <var>file-path</var></syntax>
<default>HeartbeatStorage logs/hb.dat</default>
<contextlist><context>server config</context></contextlist>

<usage>
    <p>The <directive>HeartbeatStorage</directive> directive specifies the
    path to store heartbeat data.  This flat-file is used only when
    <module>mod_slotmem_shm</module> is not loaded and
    <directive module="mod_heartmonitor">HeartbeatMaxServers</directive> is set to 0.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>HeartbeatMaxServers</name>
<description>Specifies the maximum number of servers that will be sending
heartbeat requests to this server</description>
<syntax>HeartbeatMaxServers <var>number-of-servers</var></syntax>
<default>HeartbeatMaxServers 10</default>
<contextlist><context>server config</context></contextlist>
<compatibility>The value of 0 is accepted only in 2.4.55 and above</compatibility>

<usage>
    <p>The <directive>HeartbeatMaxServers</directive> directive specifies the
    maximum number of servers that will be sending requests to this monitor
    server.  It is used to control the size of the shared memory allocated
    to store the heartbeat info when <module>mod_slotmem_shm</module> is in use.</p>
    <p>Set this to <code>0</code> to use flat-file storage instead
    of shared memory (i.e., without loading
    <module>mod_slotmem_shm</module>). When using shared memory,
    the value must be 10 or greater.</p>
</usage>
</directivesynopsis>
</modulesynopsis>