Deploying workloads to AKS in Azure - Mini Project: Build & Apply

Deploying workloads to AKS

📖 Scenario: You are working as a cloud engineer for a company that wants to deploy a simple web application on Azure Kubernetes Service (AKS). Your task is to create the necessary Kubernetes deployment and service configuration files step-by-step to deploy the application and expose it to the internet.

🎯 Goal: Build a Kubernetes deployment and service YAML configuration to deploy a web application container on AKS and expose it via a LoadBalancer service.

📋 What You'll Learn

Create a Kubernetes deployment YAML with the exact name webapp-deployment

Use the container image nginx:1.23.3 in the deployment

Set the number of replicas to 3

Create a Kubernetes service YAML named webapp-service of type LoadBalancer

Expose port 80 on the service and target port 80 on the pods

💡 Why This Matters

🌍 Real World

Deploying containerized applications on AKS is a common task for cloud engineers to make applications scalable and accessible.

💼 Career

Understanding how to write Kubernetes deployment and service YAML files is essential for roles like DevOps engineer, cloud engineer, and site reliability engineer.

1

Create the initial deployment YAML

Create a Kubernetes deployment YAML named webapp-deployment with 3 replicas using the container image nginx:1.23.3. Set the container port to 80.

Azure

# Write the deployment YAML starting with apiVersion and kind
# Your code here

Hint

Start with apiVersion: apps/v1 and kind: Deployment. Use replicas: 3 and specify the container image and port inside spec.template.spec.containers.

2

Add labels and selectors for the deployment

Add the label app: webapp to both the deployment's metadata.labels and the pod template's metadata.labels. Also add a selector.matchLabels with app: webapp to the deployment spec.

Azure

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp-deployment
  # Add label app: webapp here
spec:
  replicas: 3
  selector:
    matchLabels:
      # Add app: webapp label here
  template:
    metadata:
      # Add app: webapp label here
    spec:
      containers:
      - name: nginx-container
        image: nginx:1.23.3
        ports:
        - containerPort: 80
# Your code here

Hint

Labels help Kubernetes know which pods belong to this deployment. Add app: webapp under metadata.labels and template.metadata.labels. Also add the same label under selector.matchLabels.

3

Create the service YAML to expose the deployment

Create a Kubernetes service YAML named webapp-service of type LoadBalancer. It should select pods with label app: webapp and expose port 80 on the service, targeting port 80 on the pods.

Azure

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp-deployment
  labels:
    app: webapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: webapp
  template:
    metadata:
      labels:
        app: webapp
    spec:
      containers:
      - name: nginx-container
        image: nginx:1.23.3
        ports:
        - containerPort: 80
---
# Create the service YAML below
# Your code here

Hint

Use kind: Service with type: LoadBalancer. The selector must match the deployment's pod label app: webapp. Expose port 80 and target port 80.

4

Add final metadata and comments

Add a comment at the top of the YAML file stating # Kubernetes deployment and service for webapp. Also add a label environment: production under the deployment's metadata.labels.

Azure

# Add a comment at the top and add environment label under deployment metadata.labels
apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp-deployment
  labels:
    app: webapp
    # Add environment: production label here
spec:
  replicas: 3
  selector:
    matchLabels:
      app: webapp
  template:
    metadata:
      labels:
        app: webapp
    spec:
      containers:
      - name: nginx-container
        image: nginx:1.23.3
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: webapp-service
spec:
  type: LoadBalancer
  selector:
    app: webapp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
# Your code here

Hint

Comments start with #. Add the comment at the very top. Add the label environment: production under metadata.labels in the deployment.

Practice

1. What is the main purpose of using a Deployment in Azure Kubernetes Service (AKS)?

easy

A. To monitor the health of the AKS cluster nodes

B. To manage and maintain a specified number of app copies running

C. To expose the app to the internet

D. To store data persistently for the app

Solution

1. Step 1: Understand Deployment role in AKS

   A Deployment ensures that a specified number of replicas of an app are running and manages updates to those replicas.

2. Step 2: Differentiate from other components

   Persistent storage is handled by volumes, exposure by Services, and monitoring by Azure Monitor, not Deployments.

3. Final Answer:

   To manage and maintain a specified number of app copies running -> Option B

4. Quick Check:

   Deployment manages app replicas = A [OK]

Hint: Deployments keep app copies running smoothly [OK]

Common Mistakes:

• Confusing Deployment with Service for exposure
• Thinking Deployment stores data
• Assuming Deployment monitors nodes

2. Which kubectl command correctly applies a YAML file named app-deployment.yaml to deploy an app to AKS?

easy

A. kubectl create app-deployment.yaml

B. kubectl run app-deployment.yaml

C. kubectl apply -f app-deployment.yaml

D. kubectl deploy app-deployment.yaml

Solution

1. Step 1: Identify correct kubectl syntax for applying YAML

   The command to apply a YAML file is kubectl apply -f filename.yaml.

2. Step 2: Check other options for correctness

   kubectl create requires resource type, kubectl run is for quick pod creation, and kubectl deploy is not a valid command.

3. Final Answer:

   kubectl apply -f app-deployment.yaml -> Option C

4. Quick Check:

   Apply YAML file = kubectl apply -f [OK]

Hint: Use 'kubectl apply -f' to deploy YAML files [OK]

Common Mistakes:

• Using 'kubectl create' without resource type
• Trying 'kubectl deploy' which doesn't exist
• Confusing 'kubectl run' with applying YAML

3. Given this YAML snippet for an AKS Deployment:

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

How many pods will AKS try to run for this Deployment?

medium

A. 3

B. 2

C. 1

D. 0

Solution

1. Step 1: Identify the replicas count in the YAML

   The replicas field is set to 3, meaning AKS will run 3 pods.

2. Step 2: Confirm no other fields override replicas

   There is no override or scaling specified, so the number remains 3.

3. Final Answer:

   3 -> Option A

4. Quick Check:

   replicas: 3 means 3 pods [OK]

Hint: Check 'replicas' field for pod count [OK]

Common Mistakes:

• Ignoring the replicas field
• Confusing selector labels with pod count
• Assuming default pod count is 1

4. You applied a Deployment YAML but your pods are stuck in 'Pending' state. Which of these is the most likely cause?

medium

A. The container image name is misspelled

B. The Service type is set to ClusterIP

C. The Deployment YAML is missing the 'replicas' field

D. There are not enough cluster resources to schedule pods

Solution

1. Step 1: Understand what 'Pending' pod state means

   Pods in 'Pending' usually wait for resources like CPU or memory to be available on nodes.

2. Step 2: Evaluate options for causing Pending state

   Misspelled image causes ImagePull errors, missing replicas defaults to 1, and Service type doesn't affect pod scheduling.

3. Final Answer:

   There are not enough cluster resources to schedule pods -> Option D

4. Quick Check:

   Pending pods = resource shortage [OK]

Hint: Pending pods often mean no resources available [OK]

Common Mistakes:

• Confusing image pull errors with Pending state
• Thinking missing replicas stops pod creation
• Assuming Service type affects pod scheduling

5. You want to expose your AKS Deployment to the internet with a stable IP and load balancing. Which Kubernetes Service type should you use in your YAML?

hard

A. LoadBalancer

B. NodePort

C. ClusterIP

D. ExternalName

Solution

1. Step 1: Identify Service types and their purposes

   ClusterIP exposes service inside cluster only, NodePort exposes on node ports, LoadBalancer creates cloud load balancer with stable IP, ExternalName maps to external DNS.

2. Step 2: Choose Service type for internet exposure with stable IP

   LoadBalancer is the correct choice to get a cloud-managed IP and load balancing for external access.

3. Final Answer:

   LoadBalancer -> Option A

4. Quick Check:

   Internet exposure with stable IP = LoadBalancer [OK]

Hint: Use LoadBalancer Service for external stable IP [OK]

Common Mistakes:

• Using ClusterIP which is internal only
• Choosing NodePort which uses random ports
• Confusing ExternalName with load balancing