Appendix C. Mod_proxy_cluster connector modules

When set to on, session identifiers are checked to ensure that they are unique and have not occurred before. The default is on.

Defines a handler to display information about worker nodes in the cluster. This is defined in the Location element:

<Location $LOCATION>
  SetHandler mod_cluster-manager
  Require ip 127.0.0.1
</Location>

In this situation, $LOCATION was also defined as mod_cluster_manager.

Consider the following guidelines when accessing the $LOCATION that is defined in the Location element in your browser:

Defines how load balancers are created in the Apache HTTP Server virtual hosts. The following values are valid in CreateBalancers:

Defines whether to check that the defined Alias corresponds to the ServerName. The following values are valid for UseAlias:

ProxyPass maps remote servers into the local server namespace. If the local server has an address such as http://local.com/, the following ProxyPass directive converts a local request for http://local.com/requested/file1 into a proxy request for http://worker.local.com/file1.

ProxyPass /requested/ http://worker.local.com/

ProxyPassMatch uses regular expressions to match local paths to which the proxied URL should apply.

For either directive, ! indicates that a specified path is local, and a request for that path should not be routed to a remote server. For example, the following directive specifies that gif files should be served locally.

ProxyPassMatch ^(/.*\.gif)$ !

Defines whether to forward the original URL path to the back end without modifications.

The default value is Off. When the UseNocanon directive is set to Off, the proxy can forward modified URLs to the back end. However, if the back-end application expects the original URL path that the client requested, the modified URL path can lead to unexpected issues.

When you set the UseNocanon directive to On, the proxy can forward the original URL path to the back end without any modifications. In this situation, the proxy behavior depends on whether you also define a context and a ProxyPass directive for the requested URL in the mod_proxy_cluster.conf file. A context is also known as a virtual host definition.

Consider the following guidelines when you set the UseNocanon directive to On:

Defines the response status code that the server sends to the client when a ProxyPass or ProxyPassMatch directive does not have a matching context.

The default value is 404, which means that the server sends a Not Found error response by default.

In JBCS 2.4.51 or earlier, when a ProxyPass or ProxyPassMatch directive did not have a matching context, the server sent a 503 Service Unavailable response by default. If you want to preserve the default behavior that was available in earlier releases, set the ResponseStatusCodeOnNoContext directive to 503 instead.

Defines how the advertising mechanism is used.

The default value is Off. When set to Off, the proxy does not advertise its location.

When set to On, the advertising mechanism is used to tell worker nodes to send status information to this proxy. You can also specify a host name and port with the following syntax: ServerAdvertise On http://HOSTNAME:PORT/. This is only required when using a name-based virtual host, or when a virtual host is not defined.

Defines the multicast address to advertise on. The syntax is AdvertiseGroup ADDRESS:PORT, where ADDRESS must correspond to AdvertiseGroupAddress, and PORT must correspond to AdvertisePort in your worker nodes.

If your worker node is JBoss EAP-based, and the -u switch is used at startup, the default AdvertiseGroupAddress is the value passed via the -u switch.

The default value is 224.0.1.105:23364. If a port is not specified, the port defaults to 23364.