The PHP installers write information that the agent uses to communicate with the Controller to the Agent section of the PHP configuration files.

By default, the PHP Agent marks an HTTP error response, such as status code 4xx response as an error. When the following setting is added to the php.ini file, it will not mark the HTTP error response as an error.

agent.http_error_detection = false

This is different from some of the other Splunk AppDynamics application agents, which write this information to an XML file called controller-info.xml.

If you re-install the agent, the installer overwrites your settings only if you are using a fragments directory. It never overwrites the php.ini file. You can edit the PHP configuration files after installation to add, delete or modify these settings.

If a setting documented as required is not provided, the agent will not start. In this case, the agent logs the error to the web server error log. For example, if the controller.Hostname is not set you would see the following message in the Apache error log:

[AD agent] agent.controller.hostName is not set. Agent is disabled.

If after successful startup you remove a required setting or set it to an empty value, the change is ignored as long as the application is running, using the original value of the setting as it was at startup. If you change a required setting to a different valid value, restart the web server to apply the change.

The Controller information settings are described below: