Load balancing with Weblogic

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Load balancing with Weblogic

applies_JEE

 

The following section illustrates an example where a load balancer is configured to distribute processing into an active Bizagi cluster.

This example applies for the JEE edition in which we will use a clustered Weblogic configuration through the load balance modules in Apache HTTP Server.

Therefore and before you move on, make sure you have already set up your Weblogic cluster, as described at Clustered Weblogic configuration.

 

Keep in mind that Bizagi supports hardware or software load balancers, and it is recommended the use of a hardware-based load balancer (e.g, F5).

For more information about the general overview, refer to Configuring a load balancer.

 

 

Example

To illustrate how to configure load balancing, in this section we will describe which changes are required when using Apache HTTP Server (and its load balancing modules).

Therefore, in this example we part from having Apache HTTP Server installed in a Web server.

 

You may download this server directly from Apache HTTP Server's official webpage, and choose the version according to your platform and operating system.

The path in which Apache HTTP Server is installed, will be referred to as <APACHE_HOME> from this point on.

 

SettingBizagiInternet00_InstallingApache

 

 

Configure the load balancer to consider multiple nodes.

In our example using Apache HTTP Server and Weblogic, we specify which nodes make up the clustered configuration by editing Apache's configuration file <APACHE_HOME>\conf\httpd.conf

 

To do this, ensure you enable the necessary options as described below.

 

Edit this file to explicitly enable the service. Do this by setting:

Listen [Balancer_Server]:[Balancer_Port]

 

Make sure you enable the following modules to be used for load balancing capabilities:

LoadModule weblogic_module modules/mod_wl[encryptedb]_[version].so

<IfModule mod_weblogic.c>

WebLogicCluster [Node1]:[Port1], [Node2]:[Port2]

MatchExpression /*

</IfModule>

<Location /weblogic>

SetHandler weblogic-handler

WebLogicCluster [Node1]:[Port1], [Node2]:[Port2]

PathTrim /weblogic

</Location>

 

 

For the above, consider:

[Balancer_Server]: The name of the local server which is in charge of load balancing.

[Balancer_Port]: The port number through which the Balancer server attends requests.

[Node1] : Name (or IP address) of the Server where the first node making up the cluster is found.

[Port1] : Port number under which the first node attends requests.

[Node2] : Name (or IP address) of the Server where the second node making up the cluster is found.

[Port2] : Port number under which the second node attends requests.

[version]: Enter 20 or 22, according to the version of your Apache HTTP Server (corresponds to versions 2.0.x or 2.2.x).

[encryptedb]: The number of bits (if applies) involved in the encryption used when transferring information (optional).

You may choose to not specify any of this and leave it empty, in which case we would use the module version without this feature:

LoadModule weblogic_module modules/mod_wl_22.so

 

Notice that for each additional node your Weblogic cluster has, you will need to include additional occurrences of:

,[NodeN]:[PortN]

 

note_pin

Bizagi supports any load balancing algorithm, and the only requirement for the load balancer configuration is that sticky sessions are enabled.

 

Once you have finished editing this file, save the changes and close it.

 

 

Configure the JEE Application Server to support load balancing

Ensure that your JEE Application Server supports load balancing capabilities.

This may imply you will have to install certain plugins depending on the given Application Server and its version.

 

In this example, using Weblogic and Apache HTTP Server, will require the following actions:

 

1. Acknowlegde which Weblogic version you are using.

According to this, in Weblogic 11g versions, this path: <WEBLOGIC_HOME>\wlserver_10.3\server\plugin\ contains any required files to be installed as plugins to enable Apache HTTP Server load balancing capabilities.

 

2. Install the specific plugin file of your version, by copying this file into Apache HTTP Server's installation path at <APACHE_HOME>\modules.

Keep in mind that the plugin file should match you Weblogic platform specification and operating system.

 

To ensure this, notice that the plugins are contained inside a folder structure which classifies them according to operating systems.

Plugins are named with the following syntax: mod_wl[encryptedb]_[version].so

In this syntax, consider:

[version]: Defines for which Apache version it complies to (e.g, versions in 2.0.x or 2.2.x).

[encryptedb]: Defines the number of bits (if applies) involved in the encryption used when transferring information (e.g, 128).

You may choose to use those plugins which do not have this detail (for instance mod_wl_22.so).

 

Once you have installed this plugin, you may restart the Apache HTTP Server's service.