In this scenario, you will learn how Istio can help you gracefully handle timeouts. Systems can cause timeouts for a number of reasons, sometimes this can cause 30-60 second delays in responses. As a result, the workload is queued and has knock-on effects for the rest of the application.
By implementing a timeout, services will always return within a known time, either as a success or an error.
Handling Timeouts Between Microservices
Step 1 - Bookinfo Application
In this scenario, we'll use the Istio BookInfo sample application. The application is composed of four microservices:
- The productpage microservice is the homepage, populated using the details and reviews microservices.
- The details microservice contains the book information.
- The reviews microservice contains the book reviews. It uses the Rating microservice for the star rating.
- The ratings microservice contains the book rating for a book review.
The deployment included three versions of the reviews microservice to showcase different behaviour and routing:
- Version v1 doesn’t call the Rating service.
- Version v2 calls the Rating service and displays each rating as 1 to 5 black stars.
- Version v3 calls the Rating service and presents each rating as 1 to 5 red stars.
The services communicate over HTTP using DNS for service discovery. An overview of the architecture is shown below.
The application doesn't understand anything about Istio, Kubernetes or metrics. It could be deployed onto any system.
The Bookinfo application should have already been deployed to the Kubernetes cluster along with the Istio Control Plane.
You can view the application status via
kubectl get pods