Convert existing VM to azure-spot

Question

I cannot find in the documentation a mention of converting an existing VM to an azure-spot instance.
Nor can I see a way in the portal to do so, although all the relevant azure-spot information fields are showing for the VM - they just show it isn't a spot!

Can a VM be converted?

Answer 1

Seems like you could re-create the VM using the same technique as you would to move a VM into an availability set. (eg https://learn.microsoft.com/en-us/azure/virtual-machines/windows/change-availability-set)
I'll see if I can prototype this & will post back when I have it working

Edit: got this working. see https://gist.github.com/larryclaman/5a3bb2a7b0bb7b559b1af192469c718a

Answer 2

No, you can only set Spot pricing flag during the creation time. As of today you cannot convert the VM to Spot VM.

Answer 3

You can also achieve the same through the web portal.

The steps are:

1. Power down your VM from the VM summary page and wait for it to deallocate.
2. Go DISK page of the VM, select the link for the OS disk to look at its Overview.
3. On the overview page, click the create snapshot button to create an image of the current OS disk.
4. Give it a name, and make the snapshot type full, selecting also Zone-redundant.
5. Create the snapshot, taking note of its size.
6. Navigate to the disk page from the Azure portal homepage, and in the top left of the menu bar select the add button.
7. Create the disk as you would like, making sure the disk size is at least the size of the snapshot (it can be larger if you like). Select the source type as snapshot and select the name of the snapshot you just created.
8. Create the disk.
9. Navigate back to the Disks list page on the portal, and click into the new disk just created to view the overview page.
10. On the new disks overview page, select Create VM from the horizontal menu bar, which will start a VM creation page, with the current disk as the OS disk.
11. Be sure to select the Azure Spot Instance radio button to yes to make this a spot instance.
12. All other options are the same as using an on-demand instance.

Answer 4

Larry- thanks for your script. I was able to use it to convert from spot to regular VM. Great job!
D

Answer 5

I have created the PS script to convert PYUG to SPOT VMs. It will not work for VMs with extensions as we will be recreating with existing disks.

Function Convert-PYUG2SPOT {
    Param (
        # Set variables to your specifics
        $resourceGroup,
        $vmName,
        $subscriptionName,
        [switch]$force
    )
    $WarningPreference = 'SilentlyContinue'

    $context = Set-AzContext $subscriptionName
    Write-Output "Setting context to $($subscriptionName)"
    # Get the details of the VM to be moved to the Availability Set
    $originalVM = Get-AzVM `
        -ResourceGroupName $resourceGroup `
        -Name $vmName

    try {
        # Check whether already logged-in
        $setAzContext = (az account set --name $subscriptionName)
        $updateresource = (az resource update --resource-group $resourceGroup --name $vmName --resource-type virtualMachines --namespace Microsoft.Compute --set properties.storageProfile.osDisk.deleteOption=detach)
    }
    catch {
        Write-Host 'You need to login'
        if ($LASTEXITCODE -ne 0) { exit 1 }
    }
    # checking for dependencies
    $vm = Get-AzVM -ResourceGroupName $resourceGroup -VMName $vmName
    $extensionExist = ($vm.Extensions | Select-Object Publisher, VirtualMachineExtensionType, TypeHandlerVersion)
    if ($extensionExist) {
        $extensionExist
        Write-Host 'Make sure you note the installed extensions, that you can configure later on the converted VM.'
        Write-Host 'Please re-run the automation with the -force switch to initiate the conversion.'
    }
    if ($extensionExist -and $force) {
        Write-Host 'Initiating the conversion.'
        # Create the basic configuration for the replacement VM.
        $newVM = New-AzVMConfig `
            -VMName $originalVM.Name `
            -VMSize $originalVM.HardwareProfile.VmSize `
            -Priority 'Spot' -MaxPrice -1

        # Confgure OS Disk
        Set-AzVMOSDisk `
            -VM $newVM -CreateOption Attach `
            -ManagedDiskId $originalVM.StorageProfile.OsDisk.ManagedDisk.Id `
            -Name $originalVM.StorageProfile.OsDisk.Name

        if ($originalVM.OSProfile.WindowsConfiguration) {
            $newVM.StorageProfile.OsDisk.OsType = 'Windows'
        }
        else {
            $newVM.StorageProfile.OsDisk.OsType = 'Linux'
        }

        # Taking backup of OSdisks
        $osDiskid = $originalVM.StorageProfile.OsDisk.ManagedDisk.Id
        $osDiskName = $originalVM.StorageProfile.OsDisk.Name
        # Create Disk Snapshot
        $snapshot = New-AzSnapshotConfig -SourceUri $osDiskid -Location $originalVM.Location -CreateOption copy
        $newsnap = New-AzSnapshot `
            -Snapshot $snapshot `
            -SnapshotName "$($osDiskName)_snapshot" `
            -ResourceGroupName $resourceGroup

        $randomNumber = Get-Random -Maximum 100
        foreach ($disk in $originalVM.StorageProfile.DataDisks) {
            # Taking backup of disks
            # Get Current VM Data Disk metadata.
            $dataDiskid = $disk.ManagedDisk.Id
            $dataDiskName = ($disk.Name).ToLower()

            # Create Disk Snapshot
            $snapshot = New-AzSnapshotConfig -SourceUri $dataDiskid -Location $originalVM.Location -CreateOption copy
            $newsnap = New-AzSnapshot `
                -Snapshot $snapshot `
                -SnapshotName "$($dataDiskName)_$($randomNumber)" `
                -ResourceGroupName $resourceGroup
        }

        # Add NIC(s) and keep the same NIC as primary
        foreach ($nic in $originalVM.NetworkProfile.NetworkInterfaces) {
            if ($nic.Primary -eq 'True') {
                Add-AzVMNetworkInterface `
                    -VM $newVM `
                    -Id $nic.Id -Primary
            }
            else {
                Add-AzVMNetworkInterface `
                    -VM $newVM `
                    -Id $nic.Id
            }
        }

        if ($originalVM.AvailabilitySetReference.Id) {
            Write-Output "Warning: VM $originalVM.Name is in an availability set. Spot VMs cannot run in availability sets."
        }

        # Remove the original VM
        Remove-AzVM -ResourceGroupName $resourceGroup -Name $vmName -Force

        New-AzVM `
            -ResourceGroupName $resourceGroup `
            -Location $originalVM.Location `
            -VM $newVM `
            -DisableBginfoExtension

        foreach ($attachDisk in $originalVM.StorageProfile.DataDisks) {
            $dataDiskid = ($attachDisk.ManagedDisk.Id).ToLower()
            $dataDiskName = ($attachDisk.Name).ToLower()
            Write-Output "Attaching $($dataDiskName)"
            Write-Output $dataDiskid
            Write-Output $dataDiskName
            $vm = Get-AzVM -Name $vmName -ResourceGroupName $resourceGroup
            $vm = Add-AzVMDataDisk -VM $vm `
                -Name $dataDiskName `
                -ManagedDiskId $dataDiskid `
                -Lun $attachDisk.Lun `
                -CreateOption Attach
            Write-Output " --- Adding data disk $($dataDiskName) to $($vmName)"
            Update-AzVM -ResourceGroupName $resourceGroup -VM $vm
        }
    }
}