Exercise - Enhance the application with configmaps

  • 10 minutes

You deployed the application back end, and now you need to deploy the application front end using a ConfigMap.

Before we start

Note

This exercise is optional. If you want to complete this exercise, you'll need to create an Azure subscription before you begin. If you don't have an Azure account or you don't want to create one at this time, you can read through the instructions so you understand the information that's being presented.

Create a ConfigMap

  1. Create a new YAML file named configmap.yaml and paste in the following code to create the ConfigMap spec:

    apiVersion: v1
kind: ConfigMap
metadata:
  name: ship-manager-config
  namespace: default
data:
  config.js: |
    const config = (() => {
      return {
        'VUE_APP_BACKEND_BASE_URL': 'http://ship-manager-backend.{your-dns-zone}.aksapp.io',
      }
    })()

  2. Replace {your-dns-zone} with the value of the ZONE_NAME variable you created earlier.

  3. Save and close the file.

  4. Apply the changes to your cluster using the kubectl apply command.

    kubectl apply -f configmap.yaml

  5. Check the result by querying for the ConfigMap using the kubectl get configmap command.

    kubectl get configmap ship-manager-config

Create the application

  1. Create a new YAML file named frontend.yaml and paste in the following code to create the Deployment spec:

    apiVersion: apps/v1
kind: Deployment
metadata:
  name: contoso-ship-manager-frontend
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: contoso-ship-manager-frontend
  template:
    metadata:
      labels:
        app: contoso-ship-manager-frontend
    spec:
      containers:
        - image: mcr.microsoft.com/mslearn/samples/contoso-ship-manager:frontend
          name: contoso-ship-manager-frontend
          ports:
            - containerPort: 80
              name: http
          volumeMounts:
            - name: config
              mountPath: /usr/src/app/dist/config.js
              subPath: config.js
      volumes:
        - name: config
          configMap:
            name: ship-manager-config
---

    Notice how the ConfigMap is mounted in the Deployment object. We don't specify any keys, which means we need to specify a subPath key. The subpath is the filename inside the container.

  2. Below the three dashes, paste in the following code to create the Service and Ingress specs:

    apiVersion: v1
kind: Service
metadata:
  name: contoso-ship-manager-frontend
  namespace: default
spec:
  selector:
    app: contoso-ship-manager-frontend
  ports:
    - name: http
      port: 80
      targetPort: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: contoso-ship-manager-frontend
  namespace: default
  annotations:
    spec.ingressClassName: webapprouting.kubernetes.azure.com
spec:
  rules:
    - host: contoso-ship-manager.{your-dns-zone}.aksapp.io
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: contoso-ship-manager-frontend
                port: 
                  name: http

  3. Replace {your-dns-zone} in the Ingress with the value of the ZONE_NAME variable you created earlier.

  4. Save and close the file.

  5. Deploy the application using the kubectl apply command.

    kubectl apply -f frontend.yaml

  6. Check the result by querying the Kubernetes API using the kubectl get deployment command.

    kubectl get deployment contoso-ship-manager-frontend

    When the API is available, you should get an output similar to the following example:

    NAME                           READY   UP-TO-DATE   AVAILABLE   AGE
contoso-ship-manager-frontend  1/1     1            1           18s