Using the Machine Agent, you can supplement the existing metrics in the  Controller UI with your own custom metrics. There are many extensions currently available on the Cisco DevNet site. Some are created by  and some have been created by users.

Similar to built-in metrics, your custom metrics are subject to the following  features:  

• Automatic baselines and anomaly detection 

• Availability to display on custom dashboards

• Availability to use in policies
• Visibility of all metrics in the Metric Browser and on the Infrastructure tab (where you can display external metrics and  metrics on the same graph)
  
  

Add New Custom Metrics

To create custom metrics, you create a monitoring extension. In your extension, you define the name and path of your metric (where it appears in the metric browser tree), what type of metric it is (sum, average, and so on), and how the data for the metric should be rolled up as it ages. Any custom metric reported to the Controller through any mode must be reported at least once every 300 seconds (five minutes). One Agent can run many extensions, although you may need to increase the amount of memory for the JVM Agent. You can have multiple copies of the same extension if they are in different directories.

A custom metric can be common across nodes or associated with a specific tier. When you create a metric, you specify the path in which it will appear in the metric tree. To create a common custom metric, use the root tree path Custom Metrics in your metric declaration. To create a tier-specific metric, specify the metric path associated with that component.   

If your application uses a large number of  extensions with the Machine Agent, you may need to increase the size of the memory allocation:

% <machine_agent_home>/bin/machine-agent -Xms64m

> <machine_agent_home>\bin\machine-agent.cmd -Xms64m

Monitoring Extension Types

You can implement custom metrics using these mechanisms:  

• Using a script:
  You can write a shell script (Linux and Unix-like systems) or batch file (Windows) to report custom metrics every minute to the Machine Agent. The Machine Agent passes these metrics on to the Controller. See Build a Monitoring Extension Using Scripts.
• Using Java:
  Your custom metrics may be too complicated to collect using a script. For example, you may need to perform complex calculations or call a third-party API to retrieve the metrics. In this case, you can extend the JavaServersMonitor class to collect the metrics and report them to the Machine Agent. Your Java program extends the JavaServersMonitor class to provide your custom functionality. See Build a Monitoring Extension Using Java.
• Using HTTP:
  If you enable the Agent HTTP listener, you can post HTTP requests to the Machine Agent to send it custom metrics every minute. To do this, start the Machine Agent with a Jetty HTTP listener. See Machine Agent HTTP Listener.