Microservice architectures are built with a number of microservice components. What if one microservice goes down? Would all dependent microservices fail and make the entire system collapse? Or would the error be gracefully handled and a degraded minimum functionality provided to the user? These questions decide the success of microservice architectures.
Microservice architectures should be resilient and be able to handle service errors gracefully. Hystrix provides fault-tolerant capabilities to microservices.