Azure Runbook to resize a VM

hcl-resize-vm.ps1

param
(
    [Parameter (Mandatory = $true)]
    [string] $ResourceGroupName,    
    [Parameter (Mandatory = $true)]
    [string] $VMName,
    [Parameter (Mandatory = $true)]
    [string] $NewVMSize,
	[Parameter (Mandatory = $true)]
    [bool] $EnableAcceleratedNetworking
)

Function Get-TimeStamp {    
    return "[{0:yyyy-MM-dd} {0:HH:mm:ss}]" -f (Get-Date)    
}

Function Get-OutputObject{
 param (
        $Success,
		$VmName,
		$NewVMSize
    )

	$data = [PSCustomObject]@{		
		success = $Success
		vmName = $VmName
		newSize = $NewVMSize		
	}

	return $data
}

Write-Verbose "$(Get-TimeStamp) Importing Modules"
Import-Module -Name Az.Automation
Import-Module -Name Az.Compute
Import-Module -Name Az.Network
Import-Module -Name Az.Resources

Write-Verbose "$(Get-TimeStamp) Validating Arguments"
if (-Not $ResourceGroupName) {
    Write-Error "$(Get-TimeStamp) Runbook was missing the expected ""ResourceGroupName"" property. Args were: $args"
    exit 0
}
if (-Not $VMName) {
    Write-Error "$(Get-TimeStamp) Runbook was missing the expected ""VMName"" property. Args were: $args"
    exit 0
}

# Set the current automation connection's authenticated account to use for future Azure Resource Manager cmdlet requests.
Write-Verbose "$(Get-TimeStamp) Obtaining Service Principle Connection..."
$ServicePrincipalConnection = Get-AutomationConnection -Name "AzureRunAsConnection"
Connect-AzAccount -ServicePrincipal -ErrorAction Stop `
    -TenantId $ServicePrincipalConnection.TenantId `
    -ApplicationId $ServicePrincipalConnection.ApplicationId `
    -CertificateThumbprint $ServicePrincipalConnection.CertificateThumbprint | Write-Verbose
Set-AzContext -Subscription $ServicePrincipalConnection.SubscriptionID -ErrorAction Stop | Write-Verbose 
Write-Verbose "$(Get-TimeStamp) Logged in as AzureRunAsConnection Service Principle"

# Get the VM to be scaled up or down
Write-Verbose "$(Get-TimeStamp) Retrieving VM Information"
$vm = Get-AzVM -ResourceGroupName $ResourceGroupName -VMName $VMName -ErrorAction Stop
# Check if the VM already has the requested configuration
if ($vm.HardwareProfile.VmSize -eq $NewVMSize) {
    Write-Error "$(Get-TimeStamp) Nothing to do! The VM already has the configuration $NewVMSize"
    exit 1
}

# Collect information about the VM's network configuration
Write-Verbose "$(Get-TimeStamp) Retrieving Network Interface Information..."
$nic = Get-AzNetworkInterface -ResourceId $vm.NetworkProfile.NetworkInterfaces[0].id -ErrorAction Stop

try {
    # Change the configuration
    Write-Verbose "$(Get-TimeStamp) Changing VM Configuration..."
    $vm.HardwareProfile.VmSize = $NewVMSize    
    $result = Update-AzVM -VM $vm -ResourceGroupName $ResourceGroupName -ErrorAction Stop

	if($result.IsSuccessStatusCode)
	{
		Write-Verbose "$(Get-TimeStamp) Successfully updated the VM configuration to $NewVMSize"
		$output = Get-OutputObject -Success $true -VmName $vm.Name -NewVmSize $vm.HardwareProfile.VmSize | ConvertTo-Json
		Write-Output $output
	}
	else
	{
		Write-Verbose "$(Get-TimeStamp) Could not update the VM configuration. $ReasonPhrase"
		$output = Get-OutputObject -Success $false -VmName $vm.Name -NewVmSize $vm.HardwareProfile.VmSize | ConvertTo-Json
		Write-Output $output
	}    

} catch {
    Write-Verbose "$(Get-TimeStamp) Handling error while changing VM Configuration..."
    if ($_.Exception.Message.Contains("VMSizeIsNotPermittedToEnableAcceleratedNetworking")) {
        Write-Verbose "$(Get-TimeStamp) It appears as though the new VM Size was not accepted because it does not support Accelerated Networking."
        Write-Verbose "$(Get-TimeStamp) Attempting to disable Accelerated Networking on the VM's network interface: $($nic.Name)..."
        $nic.EnableAcceleratedNetworking = $False
        try {
            $nic | Set-AzNetworkInterface -ErrorAction Stop
        } catch {
            Write-Error "$(Get-TimeStamp) Error while disabling accelerated networking: $_"
            throw
        }
        Write-Verbose "$(Get-TimeStamp) Done. Now trying to change the VM Configuration again..."
        try {
            Update-AzVM -VM $vm -ResourceGroupName $ResourceGroupName -ErrorAction Stop
            Write-Verbose "$(Get-TimeStamp) Successfully updated the VM configuration to $NewVMSize"
        } catch {
            Write-Error "$(Get-TimeStamp) Unexpected error while updating the VM configuration after disabling accelerated networking: $_"
            throw
        }
    } else {
        Write-Error "$(Get-TimeStamp) Unexpected error while updating the VM configuration. Error code is: $($_.Exception.ErrorCode). Full Details: $_"
        throw
    }
} finally {
	if($EnableAcceleratedNetworking)
	{
		if (-Not $nic.EnableAcceleratedNetworking) {
			Write-Verbose "$(Get-TimeStamp) Attempting to restore accellerated networking on the VM..."
			try { 
				$nic.EnableAcceleratedNetworking = $True
				$nic | Set-AzNetworkInterface -ErrorAction Stop
				Write-Verbose "$(Get-TimeStamp) Restored Accelerated Networking on the network interface: $($nic.Name)"
			} catch {
				# This is expected to fail if we have configured the VM to a size that does not support it.    
				Write-Verbose "$(Get-TimeStamp) Retrieving VM Information..."        
				$vm = Get-AzVM -ResourceGroupName $ResourceGroupName -VMName $VMName -ErrorAction Stop
				Write-Verbose "$(Get-TimeStamp) Accelerated Networking not supported on the network interface $($nic.Name) with the current VM size $($vm.HardwareProfile.VmSize)"
			}
		}
	}
}