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# Conflicts: # spring-cloud-kubernetes-examples/kubernetes-circuitbreaker-ribbon-example/readme.md # spring-cloud-kubernetes-examples/kubernetes-hello-world-example/README.md # spring-cloud-kubernetes-examples/kubernetes-leader-election-example/README.md # spring-cloud-kubernetes-examples/kubernetes-reload-example/README.md # spring-cloud-kubernetes-examples/kubernetes-zipkin-example/README.md
104 lines
3.3 KiB
Markdown
104 lines
3.3 KiB
Markdown
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# Setting up the Environment
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To play with these examples, you can install locally Kubernetes & Docker using [Minikube](https://minikube.sigs.k8s.io/docs/start/) within a Virtual Machine
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managed by a hypervisor (Xhyve, Virtualbox or KVM) if your machine is not a native Unix operating system.
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When the Minikube is installed on your machine, you can start kubernetes using this command:
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```
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minikube start
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```
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You also probably want to configure your docker client to point the Minikube docker daemon with:
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```
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eval $(minikube docker-env)
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```
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This will make sure that the docker images that you build are available to the Minikube environment.
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## Kubernetes Reload Example
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This example demonstrate how to use the reload feature to change the configuration of a spring-boot application at runtime.
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The application consists of a timed bean that periodically prints a message to the console.
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The message can be changed using a config map.
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### Running the example
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Once you have your environment set up, you can deploy the application using the fabric8 maven plugin:
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```
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mvn clean install fabric8:build fabric8:deploy -Pintegration
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```
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### Changing the configuration
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Create a yaml file with the following contents:
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```yml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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name: reload-example
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data:
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application.properties: |-
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bean.message=Hello World!
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another.property=value
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```
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A sample config map is provided with this example in the *config-map.yml* file.
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To deploy the config map, just run the following command on Kubernetes:
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```
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kubectl create -f config-map.yml
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```
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As soon as the config map is deployed, the output of the application changes accordingly.
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The config map can be now edited with the following command:
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```
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kubectl edit configmap reload-example
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```
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Changes are applied immediately when using the *event* reload mode.
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The name of the config map (*"reload-example"*) matches the name of the application as declared in the *application.properties* file.
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**Note**: If you are running in a Kubernetes environment where [RBAC](https://kubernetes.io/docs/reference/access-authn-authz/rbac/) is enabled, you need to make sure that your pod has the right level of authorizations to access the K8s APIs or resources.
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To help you get started, a sample `ServiceAccount` and `RoleBinding` configuration is provided in `src/k8s` directory. These configuration needs to be applied to your K8s cluster and the newly created `ServiceAccount` needs to be attached to your pod spec like this:
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```yml
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spec:
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containers:
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image: <image_loc>
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imagePullPolicy: IfNotPresent
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livenessProbe:
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failureThreshold: 3
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httpGet:
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path: /actuator/health
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port: 8080
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scheme: HTTP
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initialDelaySeconds: 180
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successThreshold: 1
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name: spring-boot
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ports:
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- containerPort: 8080
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name: http
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protocol: TCP
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- containerPort: 9779
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name: prometheus
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protocol: TCP
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readinessProbe:
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failureThreshold: 3
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httpGet:
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path: /actuator/health
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port: 8080
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scheme: HTTP
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initialDelaySeconds: 10
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successThreshold: 1
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securityContext:
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privileged: false
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serviceAccountName: <service_account_name>
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```
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