What are custom extensions for the Machine Agent?

Custom extensions let the Machine Agent collect and report metrics beyond its built-in hardware set — anything a shell script, Java program, or other executable can measure and print in the expected format, the Machine Agent can pick up and forward to the Controller as a regular metric.

Mechanically, an extension is a small script or JAR placed in the Machine Agent's monitors directory along with a config file describing how often to run it and how to parse its output; on each interval the agent executes it, reads the reported values, and posts them into the metric tree just like a native metric.

# Example custom extension output the Machine Agent parses
name=Custom Metrics|MessageQueue|BacklogDepth,value=482
name=Custom Metrics|MessageQueue|OldestMessageAgeSeconds,value=17

This is how teams monitor things AppDynamics has no native agent for — a message broker's queue depth, a custom cache's hit ratio, or a proprietary hardware sensor — without waiting on AppDynamics to ship first-party support, and a large community-maintained catalog of ready-made extensions already covers common systems like Kafka, Redis, and HAProxy.