AzureShutdownVM-SPN.ps1

workflow Shutdown_VM
{
$Cred = Get-AutomationPSCredential -Name "Credential_Name"
$tenant = Get-AutomationVariable -Name "tenant"
Login-AzureRmAccount -Credential $Cred -ServicePrincipal -TenantId $tenant

$subscription = Get-AutomationVariable -Name "subscription"
Select-AzureRmSubscription -SubscriptionName $subscription

$VMs = Get-AzureRmVM | where {$_.Name -match 'Virtual_Machine_Name'}

ForEach -Parallel ($VM in $VMs)
{
Stop-AzureRmVM -Name $VM.Name -ResourceGroupName $VM.ResourceGroupName -Force
}
}