Introducing Istio Service Mesh for Microservices

Chapter 4. Service Resiliency

Remember that your services and applications will be communicating over unreliable networks. In the past, developers have often tried to use frameworks (EJBs, CORBA, RMI, etc.) to simply make network calls appear like local method invocations. This gave developers a false peace of mind. Without ensuring the application actively guarded against network failures, the entire system was susceptible to cascading failures. Therefore, you should never assume that a remote dependency that your application or microservice is accessing across a network is guaranteed to respond with a valid payload nor within a particular timeframe (or, at all. As Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy, once said, “A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools”). You do not want the misbehavior of a single service to become a catastrophic failure that hamstrings your business objectives.

Istio comes with many capabilities for implementing resilience within applications, but just as we noted earlier, the actual enforcement of these capabilities happens in the sidecar. This means that the resilience features listed here are not targeted toward any specific runtime; they’re applicable regardless of library or framework you choose to write your service:

Client-side load balancing

Istio augments Kubernetes out-of-the-box load balancing.

Timeout

Wait only N seconds ...