To play with these examples, you can install locally Kubernetes & Docker using [Minikube](https://kubernetes.io/docs/getting-started-guides/minikube/) within a Virtual Machine managed by a hypervisor (Xhyve, Virtualbox or KVM) if your machine is not a native Unix operating system.

When the minikube is installed on your machine, you can start kubernetes using this command:

minikube start

You also probably want to configure your docker client to point the minikube docker deamon with:

eval $(minikube docker-env)

This will make sure that the docker images that you build are available to the minikube environment.

Kubernetes Reload Example

This example demonstrate how to use the reload feature to change the configuration of a spring-boot application at runtime.

The application consists of a timed bean that periodically prints a message to the console. The message can be changed using a config map.

Running the example

Once you have your environment set up, you can deploy the application using the fabric8 maven plugin:

mvn clean install fabric8:build fabric8:deploy -Pintegration

Note: Unfortuntaly, when you deploy using the fabric8 plugin, the readyness and liveness probes fail to point to the right actuator URL due a lack of support for spring boot. This push you to edit the generated deployment inside kubernetes and change these probes which points to "path": "/health" to "path": "/actuator/health". This will make your deployment go green. This issue is already reported into the fabric8 community: https://github.com/fabric8io/fabric8-maven-plugin/issues/1178

Changing the configuration

Create a yaml file with the following contents:

apiVersion: v1
kind: ConfigMap
metadata:
  name: reload-example
data:
  application.properties: |-
    bean.message=Hello World!
    another.property=value

A sample config map is provided with this example in the config-map.yml file.

To deploy the config map, just run the following command on Kubernetes:

kubectl create -f config-map.yml

As soon as the config map is deployed, the output of the application changes accordingly. The config map can be now edited with the following command:

kubectl edit configmap reload-example

Changes are applied immediately when using the event reload mode.

The name of the config map ("reload-example") matches the name of the application as declared in the application.properties file.