PS script for moving Azure VMs into availability zones

move_vms.ps1

param (
    [string]$subscriptionId = "",
    [string]$bootDiagnosticsResourceGroup = "",
    [string]$bootDiagnosticsStorageAccountName = "",
    [string]$vmssId = "",
    [switch]$keep,
    [Parameter(Mandatory = $true)][string]$resourceGroup,
    [Parameter(Mandatory = $true)][string]$vmName,
    [Parameter(Mandatory = $true)][Int32]$zone
)

# $ErrorActionPreference = 'Stop' # Stop the script if anything goes wrong
$resourcesToDelete = [System.Collections.ArrayList]@() # If the keep flag wasn't set, these resources will be deleted after successful script completion.
$snapshotSku = "Standard_LRS" # To be used with all disk snapshots regardless of disk SKU

Login-AzAccount

if ($subscriptionId) {
    Set-AzContext -Subscription $subscriptionId
}

$sourceVM = Get-AzVM `
    -ResourceGroupName $resourceGroup `
    -Name $vmName

$location = $sourceVM.Location

Write-Host "Stopping VM $($sourceVM.Name)..."

Stop-AzVM `
    -ResourceGroupName $resourceGroup `
    -Name $vmName `
    -Force

Write-Host "VM '$($sourceVM.Name)' stopped. Snapshotting and creating new disks in zone '$zone'..."

$osDiskName = $sourceVM.StorageProfile.OsDisk.Name
$osDiskSnapshotName = ($osDiskName + "-snap")

Write-Host "Snapshotting OS disk '$osDiskName': '$osDiskSnapshotName'..."

$osDisk = (Get-AzDisk `
    -DiskName $sourceVM.StorageProfile.OsDisk.Name `
    -ResourceGroupName $resourceGroup)

$osDiskSku = $osDisk.Sku.Name

$resourcesToDelete.Add($osDisk.Id) # Delete the original OS disk on successful completion

$osDiskSnapshotConfig = New-AzSnapshotConfig `
    -SourceUri $sourceVM.StorageProfile.OsDisk.ManagedDisk.Id `
    -Location $location `
    -CreateOption Copy `
    -SkuName $snapshotSku

$osDiskSnapshot = New-AzSnapshot `
    -Snapshot $osDiskSnapshotConfig `
    -SnapshotName $osDiskSnapshotName `
    -ResourceGroupName $resourceGroup

$resourcesToDelete.Add($osDiskSnapshot.Id) # Delete the original OS disk snapshot on successful completion

# Create a new OS disk in the specified zone based on the OS disk snapshot just taken...

$newOsDiskName = ($osDiskName + "-zone-" + $zone)

Write-Host "Creating new OS disk '$newOsDiskName' from snapshot '$osDiskSnapshotName' in zone '$zone'..."

$newOsDiskConfig = New-AzDiskConfig `
    -Location $osDiskSnapshot.Location `
    -SourceResourceId $osDiskSnapshot.Id `
    -CreateOption Copy `
    -SkuName $osDiskSku `
    -Zone $zone

$newOsDisk = New-AzDisk `
    -Disk $newOsDiskConfig `
    -ResourceGroupName $resourceGroup `
    -DiskName $newOsDiskName `

Write-Host "New OS disk '$newOsDiskName' created in zone '$zone'."

foreach ($dataDisk in $sourceVM.StorageProfile.DataDisks) {
    $dataDiskSnapshotName = ($dataDisk.Name + "-snap")

    Write-Host "Snapshotting data disk '$($dataDisk.Name)': '$dataDiskSnapshotName'..."

    $dataDiskResource = (Get-AzDisk `
        -DiskName $dataDisk.Name `
        -ResourceGroupName $resourceGroup)
    
    $dataDiskSku = $dataDiskResource.Sku.Name

    $dataDiskSnapshotConfig = New-AzSnapshotConfig `
        -SourceUri $dataDisk.ManagedDisk.Id `
        -Location $location `
        -CreateOption Copy `
        -SkuName $snapshotSku

    $dataDiskSnapshot = New-AzSnapshot `
        -Snapshot $dataDiskSnapshotConfig `
        -SnapshotName $dataDiskSnapshotName `
        -ResourceGroupName $resourceGroup

    $resourcesToDelete.Add($dataDiskResource.Id) # Delete the original data disk on successful completion
    $resourcesToDelete.Add($dataDiskSnapshot.Id) # Delete the original data disk snapshot on successful completion
    
    $newDataDiskName = ($dataDisk.Name + "-zone-" + $zone)

    Write-Host "Creating new data disk '$newDataDiskName' from snapshot '$dataDiskSnapshotName' in zone '$zone'..."

    $newDataDiskConfig = New-AzDiskConfig `
        -Location $dataDiskSnapshot.Location `
        -SourceResourceId $dataDiskSnapshot.Id `
        -CreateOption Copy `
        -SkuName $dataDiskSku `
        -Zone $zone

    $newDataDisk = New-AzDisk `
        -Disk $newDataDiskConfig `
        -ResourceGroupName $resourceGroup `
        -DiskName $newDataDiskName

    Write-Host "New data disk '$newDataDiskName' created in zone '$zone'."
}

Write-Host "Configuring new VM '$($sourceVM.Name)'..."

$newVMConfig = If ($vmssId) `
    { New-AzVMConfig -VMName $sourceVM.Name -VMSize $sourceVM.HardwareProfile.VmSize -VmssId $vmssId -Zone $zone } Else `
    { New-AzVMConfig -VMName $sourceVM.Name -VMSize $sourceVM.HardwareProfile.VmSize -Zone $zone }

Write-Host "Connecting new OS disk '$newOsDiskName' to VM '$($sourceVM.Name)'..."

Set-AzVMOSDisk `
    -VM $newVMConfig `
    -CreateOption Attach `
    -ManagedDiskId $newOsDisk.Id `
    -Name $newOsDiskName `
    -Windows

Write-Host "Connecting new data disks to VM '$($sourceVM.Name)'..."

foreach ($dataDisk in $sourceVM.StorageProfile.DataDisks) {
    $newDataDiskName = ($dataDisk.Name + "-zone-" + $zone)
    
    $newDataDisk = Get-AzDisk `
        -ResourceGroupName $resourceGroup `
        -DiskName $newDataDiskName

    Add-AzVMDataDisk `
        -VM $newVMConfig `
        -Name $newDataDisk.Name `
        -ManagedDiskId $newDataDisk.Id `
        -Caching $dataDisk.Caching `
        -Lun $dataDisk.Lun `
        -DiskSizeInGB $dataDisk.DiskSizeGB `
        -CreateOption Attach
}

Write-Host "Connecting network interface(s) to source VM '$($sourceVM.Name)'..."

foreach ($nic in $sourceVM.NetworkProfile.NetworkInterfaces) {
    if ($nic.Primary -eq "True") {
        Add-AzVMNetworkInterface -VM $newVMConfig -Id $nic.Id -Primary
    }
    else {
        Add-AzVMNetworkInterface -VM $newVMConfig -Id $nic.Id
    }
}

if ($bootDiagnosticsResourceGroup -and $bootDiagnosticsStorageAccountName) {
    Write-Host "Configuring VM '$($sourceVM.Name)' to use external boot diagnostics storage account '$bootDiagnosticsStorageAccountName'..."

    Set-AzVMBootDiagnostic `
        -VM $newVMConfig `
        -Enable `
        -ResourceGroupName $bootDiagnosticsResourceGroup `
        -StorageAccountName $bootDiagnosticsStorageAccountName
}

Write-Host "Deleting original VM '$($sourceVM.Name)'..."	

Remove-AzVM `
    -ResourceGroupName $resourceGroup `
    -Name $sourceVM.Name `
    -Force

Write-Host "Starting VM '$($sourceVM.Name)' in zone '$zone'..."

$stopCreateVmLoop = $false
[int]$createVmLoopRetryCt = 0

do {
    try {
        New-AzVM `
            -ResourceGroupName $resourceGroup `
            -Location $location `
            -VM $newVMConfig `
            -DisableBginfoExtension

        Write-Host "New VM '$($sourceVM.Name)' in zone '$zone' created."

        $stopCreateVmLoop = $true
    }
    catch {
        if ($createVmLoopRetryCt -gt 3) {
            Write-Host "Tried to create VM '$($sourceVM.Name)' 3 times and failed. Check activity log for more details."
            
            $stopCreateVmLoop = $true
        } else {
            $createVmLoopSleepFor = [Math]::Pow($createVmLoopRetryCt, 2)

            Write-Host "Failed to create new VM '$($sourceVM.Name)'. Trying again in '$($createVmLoopSleepFor)' seconds..."
            Start-Sleep -Seconds $createVmLoopSleepFor

            $createVmLoopRetryCt++
        }
    }
}
while ($stopCreateVmLoop -eq $false)


if (-not $keep) {
    Write-Host "Cleaning up resources..."

    foreach ($resourceToDelete in $resourcesToDelete) { 
        Write-Host "Removing resource '$resourceToDelete'..."

        Remove-AzResource `
            -ResourceId $resourceToDelete `
            -Force
    }
}