Azure Administrator Series

Lightweight & Serverless: Moving from VMs to Azure Container Instances (ACI)

Advanced Technical Track

Virtual Machines are great, but sometimes they feel like using a sledgehammer to crack a nut. If you have a simple web app and want to avoid the overhead of managing an OS, patching, and scaling servers, it’s time to look at Containers.

In this case study, we are helping an organization transition away from a heavy on-premises VM to a “serverless” container model. Using Docker and Azure Container Instances (ACI), we’ll deploy an application in minutes without touching a single server.

The Core Concept: Why Containers?

Think of a Virtual Machine as a house — it has its own plumbing, heating, and foundation (the OS). A Container is like a pre-fab apartment. It’s isolated and has everything it needs to run, but it shares the underlying infrastructure. This makes it incredibly fast to start and very “light” on resources.

Task 1: Deploying Your First Container

We’re going to use a pre-built Docker image from the Microsoft Container Registry to launch a “Hello World” web app.

Step-by-Step Deployment:

1. Sign in to the Azure Portal.
2. Search for Container instances and click + Create.
3. On the Basics tab, configure the following:

• Resource Group: Create a new one named az104-rg9-aci-lab.
• Container name: az104-c1.
• Region: East US (or your preferred region).
• Image source: Select Quickstart images.
• Image: Choose mcr.microsoft.com/azuredocs/aci-helloworld:latest (Linux).

2. Networking: * This is crucial. Give your container a DNS name label. This must be globally unique (e.g., my-web-app-jan2026).

• Your app will live at [your-label].[region].azurecontainer.io.

3. Monitoring: For this lab, uncheck Enable container instance logs (we can still view them manually later).

4. Finalize: Click Review + Create, then Create.

The “Serverless” Advantage: Notice we didn’t pick a CPU or RAM “Size” in the same way we do for a VM. ACI just gives the container exactly what it needs to run and bills you by the second.

Task 2: Testing the Deployment & Checking the “Pulse”

Once Azure says, “Your deployment is complete,” it’s time to see if our container is actually alive.

1. Verify the FQDN

Go to the Overview blade of your container instance. Check that the status says Running. Look for the FQDN (Fully Qualified Domain Name).

2. Browse the App

Copy that FQDN and paste it into a new browser tab. You should see a “Welcome to Azure Container Instance” page. Congratulations! You just deployed a web server without actually managing a server.

3. Check the Logs

One of the best features of containers is the ability to see exactly what’s happening inside them in real-time.

1. Go back to the portal and refresh your web app page a few times to generate traffic.
2. In the Settings section of your ACI, click Containers.
3. Select the Logs tab.
4. You will see HTTP GET entries. These are the digital footprints of your browser requests hitting the container.

Key Takeaways for Your Architect’s Portfolio

• Speed: ACI is the fastest way to run a container in Azure. No VM setup, no Kubernetes cluster configuration, just code to cloud.
• Infrastructure-Free: You don’t manage the underlying host. Microsoft does.
• Lifecycle: ACI is perfect for short-lived tasks, like a data processing script that runs for 10 minutes or a simple static website.

To keep your subscription tidy, delete the resource group: Azure CLI: az group delete --name az104-rg9-aci-lab --yes --no-wait

Consider following the author for more content.