In this section, we are going to deploy the application to the cluster. For this, we need to define a Kubernetes manifest file. This defines the desired state for the cluster, such as what container images to run. We are going to use a manifest to create all the objects that are needed to deploy our sample application. This sample application is the Azure vote application and consists of a Python application and a Redis instance. The manifest will include two Kubernetes deployments: one for the frontend Python application and one for the backend Redis Cache. Two Kubernetes services will be created as well; that is, an internal service for the Redis instance and an external service so that we can access the vote application from the internet.

1. In the Cloud Shell, use nano or vi to create a file named azure-vote.yaml. 
2. Copy in the following YAML definition. Here, we have the backend application, beginning with the deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: azure-vote-back
spec:
  replicas: 1
  selector:
    matchLabels:
      app: azure-vote-back
  template:
    metadata:
      labels:
        app: azure-vote-back
    spec:
      nodeSelector:
        "beta.kubernetes.io/os": linux
      containers:
      - name: azure-vote-back
        image: redis
        resources:
          requests:
            cpu: 100m
            memory: 128Mi
          limits:
            cpu: 250m
            memory: 256Mi
        ports:
        - containerPort: 6379
          name: redis
---

3. Then, we have the service for the backend application:

apiVersion: v1
kind: Service
metadata:
  name: azure-vote-back
spec:
  ports:
  - port: 6379
  selector:
    app: azure-vote-back
---

Next, we have the deployment for the frontend application:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: azure-vote-front
spec:
  replicas: 1
  selector:
    matchLabels:
      app: azure-vote-front
  template:
    metadata:
      labels:
        app: azure-vote-front
    spec:
      nodeSelector:
        "beta.kubernetes.io/os": linux
      containers:
      - name: azure-vote-front
        image: microsoft/azure-vote-front:v1
        resources:
          requests:
            cpu: 100m
            memory: 128Mi
          limits:
            cpu: 250m
            memory: 256Mi
        ports:
        - containerPort: 80
        env:
        - name: REDIS
          value: "azure-vote-back"
---

After this, we have the service:

apiVersion: v1
kind: Service
metadata:
  name: azure-vote-front
spec:
  type: LoadBalancer
  ports:
  - port: 80
  selector:
    app: azure-vote-front

Now, deploy the application using the azure-vote manifest file:

kubectl apply -f azure-vote.yaml

The application will be deployed. This will result in the following output:

Now that we've deployed the application, we will test it.