How to create a managed image of a virtual machine or VHD
Applies to: ✔️ Linux VMs ✔️ Flexible scale sets
To create multiple copies of a virtual machine (VM) for use in Azure for development and test, capture a managed image of the VM or of the OS VHD. To create, store and share images at scale, see Azure Compute Galleries.
One managed image supports up to 20 simultaneous deployments. Attempting to create more than 20 VMs concurrently, from the same managed image, may result in provisioning timeouts due to the storage performance limitations of a single VHD. To create more than 20 VMs concurrently, use an Azure Compute Gallery (formerly known as Shared Image Gallery) image configured with 1 replica for every 20 concurrent VM deployments.
To create a managed image, you'll need to remove personal account information. In the following steps, you deprovision an existing VM, deallocate it and create an image. You can use this image to create VMs across any resource group within your subscription.
To create a copy of your existing Linux VM for backup or debugging, or to upload a Linux VHD from an on-premises VM, see Upload and create a Linux VM from custom disk.
You can use Azure VM Image Builder to build your custom image, no need to learn any tools, or setup build pipelines, simply providing an image configuration, and the Image Builder will create the Image. For more information, see Getting Started with Azure VM Image Builder.
You'll need the following items before creating an image:
An Azure VM created in the Resource Manager deployment model that uses managed disks. If you haven't yet created a Linux VM, you can use the portal, the Azure CLI, or Resource Manager templates. Configure the VM as needed. For example, add data disks, apply updates, and install applications.
Prefer a tutorial instead?
For a simplified version of this article, and for testing, evaluating, or learning about VMs in Azure, see Create a custom image of an Azure VM by using the CLI. Otherwise, keep reading here to get the full picture.
Step 1: Deprovision the VM
First you'll deprovision the VM by using the Azure VM agent to delete machine-specific files and data. Use the
waagent command with the
-deprovision+user parameter on your source Linux VM. For more information, see the Azure Linux Agent user guide. This process can't be reversed.
Connect to your Linux VM with an SSH client.
In the SSH window, enter the following command:
sudo waagent -deprovision+user
Only run this command on a VM that you'll capture as an image. This command does not guarantee that the image is cleared of all sensitive information or is suitable for redistribution. The
+userparameter also removes the last provisioned user account. To keep user account credentials in the VM, use only
Enter y to continue. You can add the
-forceparameter to avoid this confirmation step.
After the command completes, enter exit to close the SSH client. The VM will still be running at this point.
Step 2: Create VM image
Use the Azure CLI to mark the VM as generalized and capture the image. In the following examples, replace example parameter names with your own values. Example parameter names include myResourceGroup, myVnet, and myVM.
Deallocate the VM that you deprovisioned with az vm deallocate. The following example deallocates the VM named myVM in the resource group named myResourceGroup.
az vm deallocate \ --resource-group myResourceGroup \ --name myVM
Wait for the VM to completely deallocate before moving on. This may take a few minutes to complete. The VM is shut down during deallocation.
Mark the VM as generalized with az vm generalize. The following example marks the VM named myVM in the resource group named myResourceGroup as generalized.
az vm generalize \ --resource-group myResourceGroup \ --name myVM
A VM that has been generalized can no longer be restarted.
Create an image of the VM resource with az image create. The following example creates an image named myImage in the resource group named myResourceGroup using the VM resource named myVM.
az image create \ --resource-group myResourceGroup \ --name myImage --source myVM
The image is created in the same resource group as your source VM. You can create VMs in any resource group within your subscription from this image. From a management perspective, you may wish to create a specific resource group for your VM resources and images.
If you are capturing an image of a generation 2 VM, also use the
--hyper-v-generation V2parameter. for more information, see Generation 2 VMs.
If you would like to store your image in zone-resilient storage, you need to create it in a region that supports availability zones and include the
This command returns JSON that describes the VM image. Save this output for later reference.
Step 3: Create a VM from the captured image
Create a VM by using the image you created with az vm create. The following example creates a VM named myVMDeployed from the image named myImage.
az vm create \ --resource-group myResourceGroup \ --name myVMDeployed \ --image myImage\ --admin-username azureuser \ --ssh-key-value ~/.ssh/id_rsa.pub
Creating the VM in another resource group
You can create VMs from an image in any resource group within your subscription. To create a VM in a different resource group than the image, specify the full resource ID to your image. Use az image list to view a list of images. The output is similar to the following example.
"id": "/subscriptions/guid/resourceGroups/MYRESOURCEGROUP/providers/Microsoft.Compute/images/myImage", "location": "westus", "name": "myImage",
The following example uses az vm create to create a VM in a resource group other than the source image, by specifying the image resource ID.
az vm create \ --resource-group myOtherResourceGroup \ --name myOtherVMDeployed \ --image "/subscriptions/guid/resourceGroups/MYRESOURCEGROUP/providers/Microsoft.Compute/images/myImage" \ --admin-username azureuser \ --ssh-key-value ~/.ssh/id_rsa.pub
Step 4: Verify the deployment
SSH into the virtual machine you created to verify the deployment and start using the new VM. To connect via SSH, find the IP address or FQDN of your VM with az vm show.
az vm show \ --resource-group myResourceGroup \ --name myVMDeployed \ --show-details
To create, store and share images at scale, see Azure Compute Galleries.
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