Your payment service just crashed during Black Friday peak traffic. Thousands of orders are stuck mid-transaction. The recommendation engine is timing out, making the entire product page load slowly. Users are abandoning their carts. Revenue is bleeding by the second.

This scenario is not hypothetical. It happens to companies every day. In distributed systems, failures are not exceptions but expectations. Hardware fails, networks partition, software has bugs, and dependencies become unavailable.

The difference between resilient systems and fragile ones is not the absence of failures. It is how they handle failures when they inevitably occur.

In this chapter, we will explore battle-tested strategies for handling failures in distributed systems. You will learn how to build systems that bend but do not break.

Why Failures Are Inevitable