Explain advanced resiliency engineering and chaos engineering in PHP distributed systems.

Resiliency engineering designs systems to survive failures gracefully while chaos engineering proactively validates failure tolerance.

Distributed systems fail constantly.

Failures include:

Resiliency engineering assumes failures are inevitable.

Core resiliency patterns:

Prevent repeated calls to failing dependencies.

Isolate failures between workloads.

Controlled retry behavior.

Prevent indefinite waiting.

Systems remain partially functional.

Drop excess traffic intentionally.

7.…