All of the features described earlier in this guide work equally well, regardless of whether your application is running inside
Kubernetes. This is really helpful for development and troubleshooting.
From a development point of view, this lets you start your Spring Boot application and debug one
of the modules that is part of this project. You need not deploy it in Kubernetes,
as the code of the project relies on the
Fabric8 Kubernetes Java client, which is a fluent DSL that can
communicate by using http
protocol to the REST API of the Kubernetes Server.
When the application runs as a pod inside Kubernetes, a Spring profile named kubernetes
automatically gets activated.
This lets you customize the configuration, to define beans that are applied when the Spring Boot application is deployed
within the Kubernetes platform (for example, different development and production configuration).
When you include the spring-cloud-kubernetes-istio
module in the application classpath, a new profile is added to the application,
provided the application is running inside a Kubernetes Cluster with Istio installed. You can then use
spring @Profile("istio")
annotations in your Beans and @Configuration
classes.
The Istio awareness module uses me.snowdrop:istio-client
to interact with Istio APIs, letting us discover traffic rules, circuit breakers, and so on,
making it easy for our Spring Boot applications to consume this data to dynamically configure themselves according to the environment.