Resilience

In a microservices architecture, services form a web of distributed network calls. While this allows teams to build and scale services independently, it also means that the overall reliability of your system is only as strong as its weakest link. If a critical service goes down or becomes unresponsive, it can trigger a cascading failure that disrupts the entire application.

In a microservices architecture, services communicate over a network rather than in-memory calls. While this decoupling enables massive horizontal scaling and independent deployments, it also introduces a major vulnerability: the network is unreliable. At any moment, a downstream service might experience a brief network glitch, a temporary CPU spike, a quick database lock contention, or a rolling update restart. These temporary failures are known as transient faults.

In a microservices architecture, a single application is broken down into dozens or hundreds of independent, collaborating services. While this design improves modularity and scalability, it also introduces a major risk: a failure in one service can cascade and bring down the entire system. If a downstream service becomes sluggish or unresponsive, incoming requests to your upstream services will start to pile up. If they all share the same memory, CPU, or thread pool, a slow dependency can quickly exhaust all available resources, causing your entire application to crash.