Chapter 6. Install proxy server components
6.1. Apache HTTP Server modules
LoadModule manager_module modules/mod_manager.so
- Defines the location for the files in which mod_manager stores configuration details. mod_manager also uses this location to store generated keys for shared memory and lock files. This must be an absolute path name.It is recommended that this path be set explicitly and on a local drive, not an NFS share. The default value is platform/httpd specific.Valid paths are:
- Red Hat Enterprise Linux:
- The maximum number of contexts JBoss mod_cluster will use. The default value is
- The maximum number of worker nodes JBoss mod_cluster will use. The default value is
- The maximum number of hosts (aliases) JBoss mod_cluster will use. This is also the maximum number of load balancers. The default value is
- The maximum number of active session identifiers stored. A session is considered inactive when no information is received from that session within five minutes. The default value is
0, which disables this logic.
- The name of the load balancer to use when the worker node does not provide a load balancer name. The default value is
- When set to
on, nodes, aliases and contexts are persisted in files. The default value is
- When set to
on, session identifiers are checked to ensure that they are unique, and have not occurred before. The default is
WarningSetting this directive to
offcan leave your server vulnerable to replay attacks.
- Defines a handler to display information about worker nodes in the cluster. This is defined in the
<Location $LOCATION> SetHandler mod_cluster-manager Order deny,allow Deny from all Allow from 127.0.0.1 </Location>When accessing the $LOCATION defined in the
Locationelement in your browser, you will see something like the following. (In this case, $LOCATION was also defined as
Figure 6.1. mod_cluster Status
LoadModule proxy_cluster_module modules/mod_proxy_cluster.so
<VirtualHost>element to change load-balancing behavior.
- Defines how load balancers are created in the Apache HTTP Server virtual hosts. The following values are valid in
- Create load balancers in all virtual hosts defined in Apache HTTP Server. Remember to configure the load balancers in the
- Do not create balancers. When using this value, you must also define the load balancer name in the
- Create only the main server. This is the default value for
- Defines whether to check that the defined
Aliascorresponds to the
ServerName. The following values are valid for
- Ignore Alias information from worker nodes. This is the default value for
- Verify that the defined alias corresponds to a worker node's server name.
- Defines the interval in seconds between the proxy calculating the status of a worker node. The default interval is 5 seconds.
- ProxyPassMatch; ProxyPass
ProxyPassmaps remote servers into the local server namespace. If the local server has an address
http://local.com/, then the following
ProxyPassdirective would convert a local request for
http://local.com/requested/file1into a proxy request for
ProxyPass /requested/ http://worker.local.com/
ProxyPassMatchuses Regular Expressions to match local paths to which the proxied URL should apply.For either directive,
!indicates that a specified path is local, and a request for that path should not be routed to a remote server. For example, the following directive specifies that
.giffiles should be served locally.
ProxyPassMatch ^(/.*\.gif)$ !
VirtualHostelement. Its identifier in the following code snippet is
LoadModule advertise_module modules/mod_advertise.so
- Enables or disables the advertising mechanism. When set to
On, the advertising mechanism is used to tell worker nodes to send status information to this proxy. When set to
Off, the advertising mechanism is disabled.You can also specify a hostname 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.The default value is
Offbut it is automatically enabled if any
Advertisedirective is specified in defining a VirtualHost.
- Defines the multicast address to advertise on. The syntax is
AdvertiseGroup address:port, where address should correspond to
AdvertiseGroupAddress, and port should correspond to
AdvertisePortin your worker nodes.If your worker node is JBoss Enterprise Application Platform-based, and the
-uswitch is used at startup, the default
AdvertiseGroupAddressis the value passed via the
-uswitch.The default value is
126.96.36.199:23364. If port is not specified, the default port used is
- The interval (in seconds) between multicast messages advertising the IP address and port. The default value is
- Defines a string used to identify the JBoss HTTP Connector mod_cluster in JBoss Web. By default this directive is not set and no information is sent.
- Defines the URL that the worker node should use to send information to the proxy server. By default this directive is not set and no information is sent.
- Defines the address and port over which to send multicast messages. The syntax is
AdvertiseBindAddress address:port. This allows an address to be specified on machines with multiple IP addresses. The default value is