Reliability and Resilience

This chapter covers the point where managed infrastructure stops being a comfort and starts being a test of architecture. Serverless platforms absorb server failures and autoscaling mechanics, but they do not decide what should happen when a dependency times out, a message is retried twice, or one tenant’s workload begins to overwhelm a shared path.

Read the lessons in order. They move from retry and idempotency design into latency protection, failure quarantine, and blast-radius reduction. The recurring theme is that resilience in serverless systems comes from deliberate control of behavior under failure, not from assuming the platform will quietly make problems disappear.

In this section

• Retries, Backoff, and Idempotency
  Explain retry behavior in synchronous and asynchronous serverless systems, and why idempotency is one of the most important design requirements for safe reprocessing.
• Timeouts, Circuit Breakers, and Fallbacks
  Describe how functions should handle dependent-service latency, third-party failure, and overloaded downstream systems. Explain what resilience looks like in short-lived compute.
• Dead-Letter Queues and Failure Quarantine
  Show how failed events or jobs are isolated for later inspection and replay. This should be a highly practical section with operational relevance.
• Bulkheads, Isolation, and Blast Radius Reduction
  Explain techniques for keeping noisy workloads, failing workflows, or tenant-specific problems from cascading across a serverless platform.