<li><img alt="" src="../images/down.gif" /> <a href="#config">Balancer and BalancerMember configuration</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#failover">Failover</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#manager">Balancer Manager</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#health-check">Dynamic Health Checks</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#status">BalancerMember status flags</a></li>
</ul><ul class="seealso"><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">
needs to be added to your configuration:
</p>
-<pre class="prettyprint lang-config"><Location "/balancer-manager">
+ <pre class="prettyprint lang-config"><Location "/balancer-manager">
SetHandler balancer-manager
Require host localhost
</Location></pre>
<code class="directive"><a href="../mod/mod_proxy.html#balancerpersist">BalancerPersist</a></code> is enabled.
</p>
+ </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="health-check" id="health-check">Dynamic Health Checks</a></h2>
+
+
+ <p>
+ Before httpd proxies a request to a worker, it can <em>"test"</em> if that worker
+ is available via setting the <code>ping</code> parameter for that worker using
+ <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code>. Oftentimes it is
+ more useful to check the health of the workers <em>out of band</em>, in a
+ dynamic fashion. This is achieved in Apache httpd by the
+ <code class="module"><a href="../mod/mod_proxy_hcheck.html">mod_proxy_hcheck</a></code> module.
+ </p>
+
+ </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="status" id="status">BalancerMember status flags</a></h2>
+
+
+ <p>
+ In the <em>balancer-manager</em> the current state, or <em>status</em>, of a worker
+ is displayed and can be set/reset. The meanings of these statuses are as follows:
+ </p>
+ <table class="bordered">
+ <tr><th>Flag</th><th>String</th><th>Description</th></tr>
+ <tr><td> </td><td><em>Ok</em></td><td>Worker is available</td></tr>
+ <tr><td> </td><td><em>Init</em></td><td>Worker has been initialized</td></tr>
+ <tr><td><code>D</code></td><td><em>Dis</em></td><td>Worker is disabled and will not accept any requests; will be
+ automatically retried.</td></tr>
+ <tr><td><code>S</code></td><td><em>Stop</em></td><td>Worker is administratively stopped; will not accept requests
+ and will not be automatically retried</td></tr>
+ <tr><td><code>I</code></td><td><em>Ign</em></td><td>Worker is in ignore-errors mode and will always be considered available.</td></tr>
+ <tr><td><code>H</code></td><td><em>Stby</em></td><td>Worker is in hot-standby mode and will only be used if no other
+ viable workers are available.</td></tr>
+ <tr><td><code>E</code></td><td><em>Err</em></td><td>Worker is in an error state, usually due to failing pre-request check;
+ requests will not be proxied to this worker, but it will be retried depending on
+ the <code>retry</code> setting of the worker.</td></tr>
+ <tr><td><code>N</code></td><td><em>Drn</em></td><td>Worker is in drain mode and will only accept existing sticky sessions
+ destined for itself and ignore all other requests.</td></tr>
+ <tr><td><code>C</code></td><td><em>HcFl</em></td><td>Worker has failed dynamic health check and will not be used until it
+ passes subsequent health checks.</td></tr>
+ </table>
</div></div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="../en/howto/public_html.html" title="English"> en </a> |
needs to be added to your configuration:
</p>
-<highlight language="config">
+ <highlight language="config">
<Location "/balancer-manager">
SetHandler balancer-manager
Require host localhost
</Location>
-</highlight>
+ </highlight>
<note type="warning"><title>Warning</title>
<p>Do not enable the <em>balancer-manager</em> until you have <a
</section>
+ <section id="health-check">
+ <title>Dynamic Health Checks</title>
+
+ <p>
+ Before httpd proxies a request to a worker, it can <em>"test"</em> if that worker
+ is available via setting the <code>ping</code> parameter for that worker using
+ <directive module="mod_proxy">ProxyPass</directive>. Oftentimes it is
+ more useful to check the health of the workers <em>out of band</em>, in a
+ dynamic fashion. This is achieved in Apache httpd by the
+ <module>mod_proxy_hcheck</module> module.
+ </p>
+
+ </section>
+
+ <section id="status">
+ <title>BalancerMember status flags</title>
+
+ <p>
+ In the <em>balancer-manager</em> the current state, or <em>status</em>, of a worker
+ is displayed and can be set/reset. The meanings of these statuses are as follows:
+ </p>
+ <table border="1">
+ <tr><th>Flag</th><th>String</th><th>Description</th></tr>
+ <tr><td> </td><td><em>Ok</em></td><td>Worker is available</td></tr>
+ <tr><td> </td><td><em>Init</em></td><td>Worker has been initialized</td></tr>
+ <tr><td><code>D</code></td><td><em>Dis</em></td><td>Worker is disabled and will not accept any requests; will be
+ automatically retried.</td></tr>
+ <tr><td><code>S</code></td><td><em>Stop</em></td><td>Worker is administratively stopped; will not accept requests
+ and will not be automatically retried</td></tr>
+ <tr><td><code>I</code></td><td><em>Ign</em></td><td>Worker is in ignore-errors mode and will always be considered available.</td></tr>
+ <tr><td><code>H</code></td><td><em>Stby</em></td><td>Worker is in hot-standby mode and will only be used if no other
+ viable workers are available.</td></tr>
+ <tr><td><code>E</code></td><td><em>Err</em></td><td>Worker is in an error state, usually due to failing pre-request check;
+ requests will not be proxied to this worker, but it will be retried depending on
+ the <code>retry</code> setting of the worker.</td></tr>
+ <tr><td><code>N</code></td><td><em>Drn</em></td><td>Worker is in drain mode and will only accept existing sticky sessions
+ destined for itself and ignore all other requests.</td></tr>
+ <tr><td><code>C</code></td><td><em>HcFl</em></td><td>Worker has failed dynamic health check and will not be used until it
+ passes subsequent health checks.</td></tr>
+ </table>
+ </section>
+
</manualpage>