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Chaos Engineering & Resilience

Principles and practices for injecting failures, validating recovery, and designing resilient serverless systems.

Simple Explanation​

What it is​

Chaos engineering is controlled failure testing. You break things on purpose to prove your system can recover.

Why we need it​

If you only test when everything is healthy, you do not know how the system behaves during real incidents.

Benefits​

  • Higher confidence in recovery plans.
  • Fewer surprises during outages.
  • Stronger resilience under stress.

Tradeoffs​

  • Requires careful guardrails to avoid real damage.
  • Needs time to plan and analyze experiments.

Real-world examples (architecture only)​

  • Disable a region -> Verify failover.
  • Slow database -> Confirm graceful degradation.

Chaos failover

What This Lesson Covers​

  • Chaos principles and safety guardrails
  • Experiment design and blast radius control
  • Resilience patterns for serverless systems
  • Recovery metrics and success criteria
  • Game days and continuous learning

Core Principles​

  1. Start small

    • Single service, limited impact
    • Test during low-traffic windows

  2. Define success

    • Error rate, latency, and recovery time

  3. Control blast radius

    • Feature flags, canary traffic, quick rollback

Python Example: Controlled Fault Injection​

import os
import random


def handler(event, context):
	 if os.getenv("CHAOS_MODE") == "true":
		  # Inject failure 10% of the time during tests.
		  if random.random() < 0.1:
				raise RuntimeError("Injected failure for chaos test")

	 return {"status": "ok"}

Resilience Patterns to Validate​

  • Timeouts and retries with backoff
  • Circuit breakers for unstable dependencies
  • Idempotency for repeatable actions
  • Graceful degradation for non-critical paths

Project​

Design a chaos experiment for a critical workflow.

Deliverables:

  • Experiment plan and safety guardrails
  • Success metrics (RTO, error rate, latency)
  • Rollback and recovery steps

Email your work to maarifaarchitect@gmail.com.

References​