datamuc/chaos-professor

Chaos Professor is a web application that creates some chaos in the JVM.

Chaos Professor

Usage

Chaos Professor is a web application that creates some chaos in the JVM.

After cloning with git you can start the web application locally using Maven and Spring boot.

mvn spring-boot:run

The web application runs on port 8080 by default. Open your browser and point to the application (http://localhost:8080). The chaos professor web app exposes a REST API for calling some operations. Following operations are supported:

• Heap: Creates Java heap memory usage by loading random byte data into memory.
  • size: size in mb specifies the target size to allocate (default = 5mb)
  • time: time in milliseconds to keep the allocated memory (default = 3000ms)
• CPU: Creates CPU load by creating multiple threads that calculate Math.tan() values in endless loop.
  • threads: amount of threads to create (default = 10)
  • keepAlive: time to keep computing threads alive (default = 5000ms)

Examples how to use the REST API. Open your browser and hit following examples:

http://localhost:8080/chaos/heap
http://localhost:8080/chaos/heap?size=500&time=10000
http://localhost:8080/chaos/cpu
http://localhost:8080/chaos/cpu?threads=100&keepAlive=20000

Operation properties are optional so you can leave them out as you like.

Jolokia

The web application also exposes Jolokia services with a REST API. So you can access JVM related attributes in your browser:

http://localhost:8080/jolokia/read/java.lang:type=Memory/HeapMemoryUsage
http://localhost:8080/jolokia/read/java.lang:type=OperatingSystem/ProcessCpuLoad

First example reads the actual JVM memory usage. Second example reads the actual JVM CPU usage in %. The REST API returns JSON objects as response.

You can also execute JMX operations with Jolokia. For example you can call Java garbage collection.

http://localhost:8080/jolokia/exec/java.lang:type=Memory/gc