Chaos and fault injection tests simulate failures at each layer of the system (data source unavailable, model serving timeout, post-processing misconfiguration, network partition) to verify that the system degrades gracefully. Graceful degradation means no data loss, no silent accuracy degradation, proper error handling, correct logging of the failure event, and activation of failsafe mechanisms.

Gremlin, Litmus, and Chaos Monkey provide infrastructure for injecting failures in a controlled manner. The tests should cover pod crashes, network partitions between services, dependency outages (model registry unavailable, logging backend down), and resource exhaustion (CPU, memory, disk). Each test verifies that the system’s behaviour under failure matches the failsafe behaviour documented in the disaster recovery plan.

Chaos testing is conducted before every major release and periodically in production during controlled, off-peak windows. The test results are retained as Module 5 and Module 9 evidence. A system that fails ungracefully, producing incorrect outputs without error indication, represents a compliance risk for high-risk systems where every inference affects an individual’s rights.

Key outputs

• Fault injection test scenarios covering each architectural layer
• Graceful degradation verification (error handling, failsafe activation, logging)
• Pre-release and periodic production chaos testing schedule
• Module 5 and Module 9 AISDP evidence