kubernetes-reload-example

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

When using Openshift, you must assign the view role to the default service account in the current project:

oc policy add-role-to-user view --serviceaccount=default

You can deploy the application using the fabric8 maven plugin:

mvn clean install fabric8:build fabric8:deploy -Pintegration

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 Openshift (just replace oc with kubectl if you are using plain Kubernetes):

oc 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:

oc 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.