AKS (Azure Kubernetes Service) Interview Questions

Azure Kubernetes Service (AKS) is a managed container orchestration service provided by Microsoft Azure. It simplifies the deployment, management, and operations of Kubernetes by automating tasks like provisioning, upgrading, and scaling resources. 

If you're preparing for a job interview that involves AKS, it's essential to understand its core concepts, features, and best practices. This blog post covers some of the most commonly asked AKS (Azure Kubernetes Service) interview questions and answers to help you prepare effectively.

1. What is Azure Kubernetes Service (AKS)?

Answer: Azure Kubernetes Service (AKS) is a managed Kubernetes service provided by Microsoft Azure. It allows users to deploy, manage, and scale containerized applications using Kubernetes without the complexity of managing the underlying infrastructure. AKS automates tasks like health monitoring, scaling, and updates, making it easier to run Kubernetes clusters in the cloud.

2. What are the main features of AKS?

Answer: Key features of AKS include:

• Managed Kubernetes: Simplifies cluster management by automating upgrades, patching, and scaling.
• Integration with Azure Services: Seamless integration with other Azure services like Azure Active Directory (AAD), Azure Monitor, and Azure DevOps.
• Security: Provides features like role-based access control (RBAC), network policies, and integration with Azure Security Center.
• Scaling: Supports horizontal scaling of nodes and pods.
• Monitoring and Logging: Integrated with Azure Monitor and Azure Log Analytics for monitoring and logging.
• Cost Management: Only pay for the VMs in the cluster, as the Kubernetes master nodes are managed by Azure at no extra cost.

3. How do you create an AKS cluster using the Azure CLI?

Answer: To create an AKS cluster using the Azure CLI, you can use the following commands:

1. Create a Resource Group:

   az group create --name myResourceGroup --location eastus
   

2. Create the AKS Cluster:

   az aks create --resource-group myResourceGroup --name myAKSCluster --node-count 3 --enable-addons monitoring --generate-ssh-keys
   

3. Get the AKS Credentials:

   az aks get-credentials --resource-group myResourceGroup --name myAKSCluster
   

These commands create a resource group, deploy an AKS cluster with three nodes, enable monitoring, and generate SSH keys for node access. The last command configures kubectl to use the newly created cluster.

4. What is the difference between AKS and Kubernetes?

Answer: The primary difference between AKS and Kubernetes is that AKS is a managed Kubernetes service provided by Azure. Below is a table highlighting the differences:

Feature	AKS (Azure Kubernetes Service)	Kubernetes
Management	Managed by Azure	Self-managed
Control Plane	Managed by Azure, free of cost	Requires setup and management
Upgrades and Patching	Automated by Azure	Manual
Integration	Seamless integration with Azure services	Requires manual integration with services
Security	Built-in Azure security features and integrations	Custom implementation required
Cost	Pay only for worker nodes	Pay for both master and worker nodes
Scaling	Automated scaling	Manual or custom scaling setup
Monitoring and Logging	Integrated with Azure Monitor and Log Analytics	Requires third-party tools or setup
Support	Azure support	Community support or third-party services

5. How does AKS handle scaling?

Answer: AKS supports both manual and automatic scaling of the Kubernetes cluster:

• Manual Scaling: You can manually adjust the number of nodes in the cluster using the Azure CLI or the Azure portal.

  az aks scale --resource-group myResourceGroup --name myAKSCluster --node-count 5
  

• Cluster Autoscaler: AKS can automatically adjust the number of nodes in the cluster based on the resource requirements of the workloads. You can enable the cluster autoscaler when creating or updating the cluster.

  az aks update --resource-group myResourceGroup --name myAKSCluster --enable-cluster-autoscaler --min-count 1 --max-count 5
  

• Horizontal Pod Autoscaler (HPA): HPA automatically scales the number of pods in a deployment based on observed CPU utilization or other select metrics.

  apiVersion: autoscaling/v1
  kind: HorizontalPodAutoscaler
  metadata:
    name: my-deployment-hpa
  spec:
    scaleTargetRef:
      apiVersion: apps/v1
      kind: Deployment
      name: my-deployment
    minReplicas: 2
    maxReplicas: 10
    targetCPUUtilizationPercentage: 50
  

6. How do you monitor an AKS cluster?

Answer: Monitoring an AKS cluster can be achieved through various tools and integrations:

• Azure Monitor for Containers: Provides monitoring and diagnostics for AKS clusters, including performance metrics and container logs.

  az aks enable-addons --resource-group myResourceGroup --name myAKSCluster --addons monitoring --workspace-resource-id <Log Analytics Workspace ID>
  

• Prometheus and Grafana: Popular open-source tools for monitoring and visualization. You can deploy Prometheus and Grafana in your AKS cluster for advanced monitoring.

• Azure Log Analytics: Collects and analyzes logs from the AKS cluster.

• Kube-state-metrics: Exposes Kubernetes cluster state metrics to Prometheus.

7. How does AKS integrate with Azure Active Directory (AAD)?

Answer: AKS can be integrated with Azure Active Directory (AAD) to provide secure authentication and authorization for accessing the Kubernetes API server. This integration enables you to manage cluster access using AAD identities and RBAC.

1. Enable AAD Integration when Creating the Cluster:

   az aks create --resource-group myResourceGroup --name myAKSCluster --enable-aad --aad-admin-group-object-ids <AAD Group Object ID> --generate-ssh-keys
   

2. Configure RBAC in Kubernetes: Create a role binding to assign Kubernetes roles to AAD users or groups.

   apiVersion: rbac.authorization.k8s.io/v1
   kind: RoleBinding
   metadata:
     name: aad-role-binding
     namespace: default
   subjects:
   - kind: User
     name: user@domain.com
     apiGroup: rbac.authorization.k8s.io
   roleRef:
     kind: Role
     name: <role-name>
     apiGroup: rbac.authorization.k8s.io
   

8. What is a Kubernetes Ingress, and how is it used in AKS?

Answer: A Kubernetes Ingress is an API object that manages external access to services within a Kubernetes cluster, typically HTTP and HTTPS. Ingress can provide load balancing, SSL termination, and name-based virtual hosting.

Example of Ingress Configuration:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: example-service
            port:
              number: 80

In AKS, you can use NGINX or Azure Application Gateway as the Ingress controller to manage Ingress resources.

9. How do you perform rolling updates in AKS?

Answer: Rolling updates in AKS are performed using Kubernetes deployment objects. The rolling update strategy allows you to update the application without downtime by gradually replacing old pods with new ones.

Example of Deployment with Rolling Update Strategy:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-deployment
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
      maxSurge: 1
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-container
        image: my-image:latest
        ports:
        - containerPort: 80

To update the deployment:

kubectl set image deployment/my-deployment my-container=my-image:new-version

10. How can you secure your AKS cluster?

Answer: To secure an AKS cluster, follow these best practices:

• Enable RBAC: Use role-based access control to manage permissions.
• Network Policies: Implement network policies to control traffic flow between pods.
• Secrets Management: Store sensitive information using Kubernetes secrets and integrate with Azure Key Vault.
• Pod Security Policies: Define and enforce security policies for pod configurations.
• Image Scanning: Scan container images for vulnerabilities before deployment.
• Audit Logs: Enable and monitor audit logs for security events.
• Secure Access: Use AAD integration for authentication and enforce secure access to the API server.

11. How do you deploy applications to AKS?

Answer: To deploy

applications to AKS, follow these steps:

1. Prepare the Kubernetes Manifest Files: Define your application, services, deployments, and other Kubernetes objects in YAML files.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: my-deployment
   spec:
     replicas: 3
     selector:
       matchLabels:
         app: my-app
     template:
       metadata:
         labels:
           app: my-app
       spec:
         containers:
         - name: my-container
           image: my-image:latest
           ports:
           - containerPort: 80
   

2. Deploy to AKS using kubectl:

   kubectl apply -f deployment.yaml
   

3. Verify the Deployment:

   kubectl get deployments
   kubectl get pods
   

4. Expose the Deployment (if needed):

   apiVersion: v1
   kind: Service
   metadata:
     name: my-service
   spec:
     selector:
       app: my-app
     ports:
       - protocol: TCP
         port: 80
         targetPort: 80
     type: LoadBalancer
   

   kubectl apply -f service.yaml
   

12. What advantages does AKS provide?

Answer: AKS provides several advantages:

• Managed Service: Simplifies Kubernetes cluster management by automating tasks like upgrades, patching, and scaling.
• Cost-Effective: Only pay for the VMs (worker nodes), as the control plane is managed by Azure at no extra cost.
• Integration: Seamless integration with Azure services like Azure Active Directory, Azure Monitor, and Azure DevOps.
• Security: Built-in features like RBAC, network policies, and integration with Azure Security Center to enhance security.
• Scalability: Supports horizontal scaling of nodes and pods to handle varying workloads efficiently.
• High Availability: Provides high availability with features like multi-region clusters and automated failover.
• Monitoring and Logging: Integrated with Azure Monitor and Azure Log Analytics for comprehensive monitoring and logging.
• Developer Productivity: Simplifies development and operations with tools like Azure DevOps and Visual Studio Code extensions.

Conclusion

Azure Kubernetes Service (AKS) simplifies the deployment, management, and operations of Kubernetes clusters in the cloud. Understanding its core concepts, features, and best practices is crucial for any developer or DevOps engineer working with containerized applications. 

This blog post covered some of the most commonly asked AKS interview questions, helping you prepare effectively for your next interview. By mastering these concepts, you will be well-equipped to tackle any AKS-related challenges you may encounter.