2.2 Configure the application

In this stage, we show you how to configure your application. For this lab the application of the previous lab is used.

Task 2.2.1: Update application port inside deployment

We will change the port of the application. With this change we need to adapt the deployment first. There are three ports to change. The container port itself, and the ports for the liveness/readiness probes.

apiVersion: apps.openshift.io/v1
kind: DeploymentConfig
metadata:
  annotations:
    image.openshift.io/triggers: '[{"from":{"kind":"ImageStreamTag","name":"data-producer:rest"},"fieldPath":"spec.template.spec.containers[?(@.name==\"data-producer\")].image"}]'
  labels:
    app: data-producer
    application: amm-techlab
  name: data-producer
spec:
  replicas: 1
  selector:
    deploymentConfig: data-producer
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        application: amm-techlab
        deploymentConfig: data-producer
    spec:
      containers:
        - image: data-producer
          imagePullPolicy: Always
          livenessProbe:
            failureThreshold: 5
            httpGet:
              path: /health/live
              port: 8080
              scheme: HTTP
            initialDelaySeconds: 3
            periodSeconds: 20
            timeoutSeconds: 15
          readinessProbe:
            failureThreshold: 5
            httpGet:
              path: /health/ready
              port: 8080
              scheme: HTTP
            initialDelaySeconds: 3
            periodSeconds: 20
            timeoutSeconds: 15
          name: data-producer
          ports:
            - containerPort: 8080
              name: http
              protocol: TCP
          resources:
            limits:
              cpu: '1'
              memory: 500Mi
            requests:
              cpu: 50m
              memory: 100Mi
  triggers:
    - imageChangeParams:
        automatic: true
        containerNames:
          - data-producer
        from:
          kind: ImageStreamTag
          name: data-producer:rest
      type: ImageChange
    - type: ConfigChange

source

Update the application port from 8080 to 8081 using oc patch:

oc patch dc/data-producer --type "json" -p '[{"op":"replace","path":"/spec/template/spec/containers/0/ports/0/containerPort","value":8081}]'

deploymentconfig.apps.openshift.io/data-producer patched

Update also the ports of the liveness and readiness probes from 8080 to 8081 using oc patch:

oc patch dc/data-producer --type "json" -p '[{"op":"replace","path":"/spec/template/spec/containers/0/livenessProbe/httpGet/port","value":8081}]'
oc patch dc/data-producer --type "json" -p '[{"op":"replace","path":"/spec/template/spec/containers/0/readinessProbe/httpGet/port","value":8081}]'

Verify the changed port of the pod by describing the DeploymentConfig using oc describe.

oc describe deploymentconfig data-producer

The pod does not start because that the readiness probe fails. Now we have to change the application to use the port 8081 for serving its endpoint.

Task 2.2.2: Configure application

There are several options how to configure a Quarkus application. We’ll show how to do it with environment variables. You can overwrite every property in the application.properties file with the corresponding environment variable. (eg. quarkus.http.port=8081 in the application.properties is the same like QUARKUS_HTTP_PORT=8081 as an environment variable) Quarkus: overriding-properties-at-runtime

The environment of the DeploymentConfig has to be extended with a new environment variable named QUARKUS_HTTP_PORT.

First, let’s check the environment:

oc set env dc/data-producer --list

# deploymentconfigs/data-producer, container data-producer

There are no environment variables configured.

Add the environment variable QUARKUS_HTTP_PORT with the value 8081 with oc set env.

oc set env dc/data-producer QUARKUS_HTTP_PORT=8081

deploymentconfig.apps.openshift.io/data-producer updated

The variable should be configured now. Check it by listing the environment of the DeploymentConfig again.

oc set env dc/data-producer --list

Expected output of the environment listing:

# deploymentconfigs/data-producer, container data-producer
QUARKUS_HTTP_PORT=8081

Task 2.2.3: Verify application

Changing the environment of a deployment triggers a rollout of the application pod. After the container has started successfully, the application should be reachable again.

Check if the changes were applied correctly. Open your browser and navigate to your application: https://data-producer-<username>.techlab.openshift.ch/data

Important notes

We showed how to change the OpenShift resources using the commands oc patch and oc set env. This is good for developing or debugging the setup of an application project.

For changing stages and productive environments, we propose updating the YAML representations inside the Git repository and apply the files again.

Solution

The needed resource files are available inside the folder manifests/02.0/2.2/ of the techlab github repository.

If you weren’t successful, you can update your project with the solution by cloning the Techlab Repository git clone https://github.com/puzzle/amm-techlab.git and executing this command:

oc apply -f manifests/02.0/2.2/