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
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:
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.