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Configuration file

XML structure

Published at 18/09/2003 21:42:35
By Juan M. Casillas

XML configuration file

Load Balancer?s configuration is stored in a XML-based file. This file has a known structure, and is defined following the XML rules & syntax. You can configure Load Balancer as you want, the tag?s configuration order is not relevant. But I like to put first the internal configuration, then the plugin configuration, and so on. In this section, I will talk about the file?s general structure, and in the following ones, I talk about the specific sections.

The XML tag

The first tag that is mandatory for the configuration file is the xml tag. This tag has two fields. The first one is the version that must be 1.0 and the second one is the comment that defines a comment about the contents of the xml block. Here we can find a string with the name of the program. So your configuration directives must go after the xml tag:

<?xml version="1.0" comment="LoadBalancer">

Next, you have to define a config tag. This tag don?t have any parameters, and define a configuration block. All your configuration directives should go between this tag.

<config>
[...]
</config>

The coreparams tag

This tag define the basic configuration parameters for Load Balancer. This tag must be defined in the configuration file. Inside this tag you can configure things like the number of threads, the server timeout interval, type of log file, and so on.

The module configuration section

In this section goes the module configuration directives. This directives are the rule plugin parameters, the rule plugin rules, and so on. In the following sections this rules will be explained in deep.

The polling interface section

Here you can configure the parameters for the polling interface plugins and directives.

Attachto tag

This section allows you to configure the host address and the port when Load Balancer will listen. For now, Load Balancer only can listen in one address:port pair, but in the future, Load Balancer will listen in more address (and ports). This is very useful if your Load Balancer machine has more than one network interfaces.

Allowfrom tag

Here you can configure the client address filters so all the client address that matches the rules, will be accepted (if not, the connection will be rejected). This rules support regular expressions, so you can define network ranges.

Serverfarm tag

Inside this configuration directive, you will be able to configure your server farm. The server farm will be built from clusters, and clusters will be built form servers. You should plan before configure Load Balancer your network topology (physical and logical).

Comments and sample configuration

The configuration file follows all the XML syntax and rules; so you can use the  tags to insert comments inside the configuration file, and to comment some configuration directives. Also, you can find a sample configuration file here. This file is the configuration for my developement environment, and should work for you with some minor changes.