Appian uses .properties and .xml files to set or modify standard configuration settings. This page describes how to set custom parameters in these files so that your customizations are retained whenever Appian is updated.

Custom Properties

Most system settings can be centrally managed by configuring a single properties file called custom.properties located at <APPIAN_HOME>/conf/. In multiple server environments, the contents of this file must be identical on all Appian servers.

• The custom.properties file you create is not overwritten when an upgrade occurs.

A custom.properties.example file is installed in the same directory to provide you with general examples. Be sure you are familiar with each setting in the example file before implementing its settings.

• If you enable the settings listed in this example file without configuring it properly for your environment, the Appian Engines may not start.

Most properties can safely be left at their default settings. For any properties that must be set for the system to work correctly, see also: Required Configurations.

Once the custom.properties file is created and Appian is running, some properties can be read dynamically while others require the application server to restart.

The table below lists the various property prefixes and whether or not changes to them require the Application Server to be restarted to have the changes take effect.

Logging Options

The filenames, locations, and content of log files can be configured using appian_log4j.properties file.

See also: Modifying Log Output

Server Configurations

Appian allows you to manage server configurations using a custom topology file. An example file named appian-topology.xml.example is included in the following location:

• <APPIAN_HOME>/conf/

Common uses for a custom topology configuration file include:

• Configuring Port Numbers

• High Availability and Distributed Installations

XML File Properties

To set XML file properties, you need to create a custom version of each modified property file. The benefit of having a custom version is that it does not need to be merged on each upgrade of Appian.

The tables in this section list Appian XML files supported for customization and configuration and provide the following information:

• XML File: Name of the configurable XML file.
• Custom XML File Name Pattern: Describes the file-path and names that can be used for the custom XML file.
  • An asterisk (*) represents a variable in the file path or a user-defined file-name suffix.
• Required Element or Attribute: Lists the XML node(s) that must exist in the custom XML file in order to create a new configuration object or override an existing one.
  • The text in parentheses is the name of the attribute that uniquely identifies the object — if surrounded by XML tag brackets < >, it lists the name of the element whose value uniquely identifies the object.
  • If no parentheses or tag brackets are listed, the presence of the node in the custom XML overrides the node in the base XML.

Partially Overriding XML Files

To partially override the XML files listed in this section, complete the following:

1. Create a new XML file.
2. Append a user-defined property to the filename.
   • For example, to override a property in an XML file named jms-topics.xml, create a file named jms-topics-custom.xml.
3. Copy over only the element that you want to override into the new file.
4. Place the custom element inside any parent element(s) that appear in the original file’s hierarchy.

   • For example, you could add the following elements and attributes:

     <topics>

     <topic name="CustomQueueOrTopic"> CustomValue </topic>

     </topics>

5. Save the custom configuration file to the same directory as the original.

When customizing the XML files in the table below, the following rules apply:

• You can add new configuration objects to the custom XML file.
• You can override the value of an existing configuration by changing the value listed for the same unique identifier.
• You must append a user-defined suffix to your custom XML file.
• You can use multiple custom XML files.

Customizing locale-config.xml

The following rules apply when customizing the locale-config.xml:

• You can add a new configuration object in your custom XML file.
• You must append a user-defined suffix to your custom XML file.
• You cannot override the value of an existing configuration.
• Only list customizations.

Deleting Configuration Settings

Generally, configuration settings cannot be deleted. Cache settings can be disabled by adding an override XML file.

To do so, complete the following:

1. Match the existing cache setting in an override file using the following element pattern:
   • /cache-configurations/cache-configuration@key
2. Add the following attribute to the cache sub-element:
   • enabled='false'
   • For a user interface XML configuration, categories, palettes, and palette items can be disabled by adding an override XML file.
3. Match the existing configuration in an override file using the following element patterns:
   • /palette-categories/palette-category@name /palette-categories/palette-category@name/palette@name
     — or —
   • /palette-categories/palette-category@name/palette@name/item@name
4. Add the following attribute:
   • <tt>enabled='false'</tt>

For example, to disable the Palette with the <tt><name>Events</name></tt>, add a file named palette-config-disable-events.xml with the following content:

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<palette-categories xmlns:xsi="<a href="http://www.w3.org/2001/XMLSchema-instance" class="external free" title="http://www.w3.org/2001/XMLSchema-instance" rel="nofollow">http://www.w3.org/2001/XMLSchema-instance</a>" xsi:noNamespaceSchemaLocation="/process/conf/xmlvalidation/palette.xsd">
<palette-category name="Standard Nodes">
    <palettes>
      <palette enabled="false">
         <name>Events</name>
      </palette>
    </palettes>
  </palette-category>
</palette-categories>