Graceful degradation

What you'll be able to do

1. 1Explain how sorting dependencies into critical and optional lets a page keep its core job when an optional dependency fails, and why waiting on an optional call can still take the page down.
2. 2Predict what users see and which requests still succeed when a given dependency fails, with and without a degraded mode.
3. 3Choose a response for each dependency's failure — hide the feature, serve cached or default data, fail open or fail closed — and avoid fallbacks that are rarely exercised or move the load elsewhere.

Inside the lesson

steps

11

questions

14

simulations

3

You guess first, then run the system and see if you were right.

More on the Resilience Line

1. Failure modes and availabilityOpen9 min
2. Timeouts — capping the waitMembers9 min
3. Retries — with backoff and jitterMembers12 min
4. Circuit breakerMembers10 min
5. Bulkhead — walls between workloadsMembers12 min
6. Load shedding — turning the excess awayMembers12 min
7. Backpressure — a queue that says noMembers11 min
8. Rate limiting — a budget for each callerMembers12 min