In this post, we’ll walk you through deploying a Docker image on an Azure Kubernetes Service (AKS) cluster and testing it using cURL. This process involves creating a Docker image, registering it with the Azure Container Registry, pulling it onto a node, and using it for testing.

Prerequisites

• Azure CLI installed
• Docker installed
• Azure subscription with access to AKS

Step 1: Log in to Your Azure Account

To begin, log in to your Azure account using the Azure CLI:

az login

After logging in, you’ll see a list of subscriptions you have access to. Select the subscription associated with your AKS cluster.

Step 2: Create a Docker Image

We’ll create a simple Docker container with cURL installed. This will allow us to ping URLs from within the container.

Create a Dockerfile with the following content:

FROM ubuntu:latest RUN apt-get update && apt-get install -y curl

Build the Docker image using the command:

docker build -t <acr_name>.azurecr.io/ubuntu-curl:0.1 .

Replace <acr_name> with your Azure Container Registry (ACR) name.

Step 3: Push the Docker Image to Azure Container Registry

Next, log in to the ACR to push the Docker image:

az acr login --name <acr_name>

Once logged in, push the image to the registry:

docker push <acr_name>.azurecr.io/ubuntu-curl:0.1

Step 4: Connect to the AKS Cluster

Retrieve the credentials for your AKS cluster:

az aks get-credentials --resource-group <resource_group_name> --name <aks_cluster_name> --admin

Replace <resource_group_name> and <aks_cluster_name> with your resource group and cluster name.

Step 5: Debug a Node Using the Docker Image

To debug a node, use kubectl to list the nodes in your cluster:

kubectl get node -o wide

This command will display the nodes in your cluster. Note the name of the node you wish to debug. Then, run the following command to create a debugging pod on that node using your Docker image:

kubectl debug node/<node_name> -it --image=<acr_name>.azurecr.io/ubuntu-curl:0.1

Replace <node_name> with the name of your node and <acr_name> with your ACR name.

You should see an output similar to:

Creating debugging pod node-debugger-aks-nodepool1-37663765-vmss000000-bkmmx with container debugger on node aks-nodepool1-37663765-vmss000000.

If you don’t see a command prompt, try pressing enter. root@aks-nodepool1-37663765-vmss000000:/#

Step 6: Test Connectivity Using cURL

With the pod running, you can use cURL to test connectivity:

curl <url>

Replace <url> with the URL you wish to test.

Step 7: Clean Up

After completing your debugging, clean up the debugging pod to avoid unnecessary resource usage:

kubectl get pods

Find the pod with “debug” in its name and delete it:

kubectl delete pod <pod_name>

Replace <pod_name> with the name of the debugging pod.

Conclusion

In this guide, we’ve walked through creating and deploying a Docker image to an AKS cluster, testing it using cURL, and cleaning up resources. This process is helpful for debugging and testing in Kubernetes environments.