Azure Hands-On - Scaling Apps, AutoScaling Cluster, HPA, and Config Network Policies on AKS

📝Introduction

In this hands-on lab, we walked through setting the Scaling of the App deployment, enabling an AutoScaler on the Cluster, enabling HPA(Horizontal Pod AutoScaler), and configuring Network Policies on Azure AKS.

📝Log in to the Azure Management Console

Using your credentials, make sure you're using the right Region. In my case, I am using the region France Central in my Cloud Playground Sandbox.

📌Note: You can also use the VSCode tool or from your local Terminal to connect to Azure CLI

More information on how to set it up is at the link.

📝Prerequisites:

Update to PowerShell 5.1, if needed.
Install .NET Framework 4.7.2 or later.
Visual Code
Web Browser (Chrome, Edge)
Azure CLI installed
Azure subscription
Docker installed

📝Setting an Azure Storage Account to Load Bash or PowerShell

Click the Cloud Shell icon (>_) at the top of the page.

Click PowerShell.

Click Show Advanced Settings. Use the combo box under Cloud Shell region to select the Region. Under Resource Group and Storage account(It's a globally unique name), enter a name for both. In the box under File Share, enter a name. Click ***Create storage (***if you don't have any yet).

📝Set up your Azure AKS environment

Login to Azure:
```
  az login
```
Set the subscription (if you have multiple):

 az account set subscription <your-subscription-id>

📝Create a Resource Group

az group create --resource-group <nameResourceGroup> --location <region>

📝Create an Azure Container Registry (ACR)

az acr create --resource-group <nameResourceGroup> --name <nameContainerRegistry>

📝 Build and Push Docker Image to ACR

Login to ACR:

  az acr login --name <nameContainerRegistry>

Create a Dockerfile

Create an Dockerfile in-your-project directory. Here’s an example Dockerfile for a simple Nginx HTML webpage:
```
  FROM nginx:alpine
  COPY index.html /usr/share/nginx/html
```
Build Docker image:
```
  docker build -t <nameapp>:v1 .
```

Tag the Docker image:

 docker tag <nameapp>:v1 <nameContainerRegistry>.azurecr.io/<nameapp>:v1

Push the Docker image to ACR:

  docker push <nameContainerRegistry>.azurecr.io/<nameapp>:v1

📝Create an AKS Cluster

az aks create --resource-group <nameResourceGroup> --name <nameAKSCluster> --node-count 2 --generate-ssh-keys --vm-set-type VirtualMachineScaleSets --node-vm-size Standard_B2s_v2 --attach-acr <nameContainerRegistry>

📝 Connect to AKS Cluster

Use the Azure Cloud Shell to check your AKS Cluster resources, by following the steps below:

Go to Azure Dashboard, and click on the Resource Group created for this Lab, looking for your AKS Cluster resource.
On the Overview tab, click on Connect to your AKS Cluster.
A new window will be opened, so you only need to open the Azure CLI and run the following commands.
After that, you can run some Kubectl commands to check the default AKS Cluster resources.

📝Deploy the Application to AKS

Create a Kubernetes deployment yaml file (deployment.yaml):

 apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: <nameapp>
 spec:
   replicas: 2
   selector:
     matchLabels:
       app: <nameapp>
   template:
     metadata:
       labels:
         app: <nameapp>
     spec:
       containers:
       - name: <nameapp>
         image: <nameContainerRegistry>.azurecr.io/<nameapp>:v1
         ports:
         - containerPort: 8080
 ---
 apiVersion: v1
 kind: Service
 metadata:
   name: <nameapp>
 spec:
   type: LoadBalancer
   ports:
     - port: 80
       targetPort: 8080
   selector:
     app: <nameapp>

Apply the deployment and create a namespace to separate the resources:
```
  kubectl apply -f deployment.yaml --namespace <name_namespace>
```

Checking the resources created and running into the AKS Cluster:

  kubectl get pods --namespace <name_namespace>
  kubectl get svc --namespace <name_namespace>
  kubectl get deployment --namespace <name_namespace>
  kubectl describe pod <namepod> --namespace <name_namespace>

Check if you can access your App via your browser.

📝Scale the App Deployment

We will Scale the App previously deployed in 2 replicas to 4 replicas.

kubectl scale deployment <nameapp> --replicas=4 --namespace <name_namespace>

Check the new resources scaling:

📝View Logs from the PODs

View the logs of a specific pod.

kubectl logs <namepod> --namespace <name_namespace>

📝Configuring Autoscaling

Enable Cluster Autoscaler

Enable the cluster AutoScaler option for the AKS cluster.

az aks update  --resource-group <namerg> --name <nameAKSCluster> --enable-cluster-autoscaler --min-count 1 --max-count 4

nable Horizontal Pod Autoscaler

Apply a Horizontal Pod Autoscaler(HPA) to the App deployment

Create a hpa.yaml file.

kubectl apply -f hpa.yaml

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler       
metadata:
  name: <nameapp>
  namespace: <nameapp>
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: <nameapp>
  minReplicas: 1
  maxReplicas: 6
  targetCPUUtilizationPercentage: 50

📝Configuring Network Policies

Create a Network Policy

Define a network policy to restrict traffic to the App .pods.

Create a network-policy.yaml file.

kubectl apply -f network-policy.yaml

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: <name>-network-policy
  namespace: <nameapp>
spec:

  podSelector:
    matchLabels:
      app: <nameapp>
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: <nameapp>
    ports:
    - protocol: TCP
      port: 80
  egress:
  - to:
    - podSelector:
        matchLabels:
          app: <nameapp>
    ports:
    - protocol: TCP
      port: 80

📌Note - At the end of each hands-on Lab, always clean up all resources previously created to avoid being charged.

Congratulations — you have completed this hands-on lab covering the basics of setting the Scaling of the App deployment, enabling an AutoScaler on the Cluster, enabling HPA(Horizontal Pod AutoScaler), and configuring Network Policies on Azure AKS.

Thank you for reading. I hope you understood and learned something helpful from my blog.

Please follow me on Cloud&DevOpsLearn and LinkedIn, franciscojblsouza