Create an Azure Linux 3.0 virtual machine with Cobalt 100 processors
Introduction
Build and run Azure Linux 3.0 on an Arm-based Azure virtual machine
Create an Azure Linux image for Arm
Transfer the image to Azure
Start an Azure virtual machine with the new image
Next Steps

  Log an issue

  Fork and edit

  Discuss on Discord

About this Learning Path

Skill level:  Advanced
Reading time:  2 hrs
Last updated:  09 Sep 2026
Skill level:
  Advanced
Reading time:
  2 hrs
Last updated:
  09 Sep 2026
Author:Jason Andrews, Arm
Arm IP:Neoverse
Tags: Containers and Virtualization Microsoft Azure Cobalt Linux QEMU Azure CLI
Author:
  • Jason Andrews, Arm
Arm IP:
Neoverse
Tags:
Containers and Virtualization Microsoft Azure Cobalt Linux QEMU Azure CLI

Who is this for?

This is an advanced topic for developers who want to run Azure Linux 3.0 on Arm-based Cobalt 100 processors in a custom virtual machine.

What will you learn?

After completing this Learning Path, you'll be able to perform the following tasks:

  • Use QEMU to create a raw disk image
  • Boot a virtual machine using an AArch64 ISO and install Azure Linux 3.0
  • Convert the raw disk image to VHD format
  • Upload the VHD file to Azure
  • Use Azure Shared Image Gallery (SIG) to create a custom image
  • Create an Azure Linux 3.0 virtual machine on Arm using the Azure CLI and the custom image

Prerequisites

Before starting, you'll need the following prerequisites:

  • A Microsoft Azure account with permission to create resources, including instances using Cobalt 100 processors
  • A Linux machine with QEMU and the Azure CLI installed and authenticated

Summary

AI-assisted

This summary was drafted with an approved AI-assisted workflow and reviewed by Arm contributors before publication. Human technical review remains part of the process so the final page reflects engineering rigor, accuracy, and Arm editorial standards.

Close
?
You’ll build a custom Azure Linux 3.0 image for Arm and deploy it on Cobalt 100-based virtual machines. Starting from the Azure Linux aarch64 ISO, you’ll use QEMU to create a raw disk, boot the installer, and produce a working system image. You’ll convert the disk to a fixed-size VHD, upload it to Azure, and register it in Azure Shared Image Gallery using the Azure CLI. With the image ID, you’ll create a new VM on Arm-based Cobalt 100 processors. You’ll explore key decisions around image format, resource naming, and region/size selection, and finish with a VM launched from the custom image.

Frequently asked questions

AI-assisted

These FAQs were drafted with an approved AI-assisted workflow and reviewed by Arm contributors before publication. Human technical review remains part of the process so the final page reflects engineering rigor, accuracy, and Arm editorial standards.

Close
?
Which ISO architecture should I download for the QEMU installation?
Use the Azure Linux 3.0 aarch64 ISO referenced in the project README. The steps boot QEMU with this ISO to install the OS onto a raw disk image.
Does the VHD need to be fixed-size before uploading to Azure?
Yes. The procedure converts the installed disk to a fixed-size VHD before upload, and the later steps assume this format when registering the image.
What environment variables should I set before running the Azure CLI upload and image registration steps?
Set RESOURCE_GROUP, LOCATION, and STORAGE_ACCOUNT as shown in the steps. Choose a LOCATION where Cobalt 100 processors are available to your subscription.
How do I confirm that my image registration in Shared Image Gallery succeeded?
After registration, obtain an image ID from the Shared Image Gallery. You will reference this IMAGE_ID in the az vm create command; having and using it confirms the image is ready.
What credentials are configured when creating the VM with `az vm create`?
The example uses --admin-username to define the Linux user and --generate-ssh-key to create an SSH key locally. This sets up key-based SSH access for the specified admin user.
Next