Provision Virtual Machines in Parallel using New Workflow Feature in PowerShell V3

PowerShell Workflow is one heavy duty feature which comes bundled with PowerShell v3, From my personal experiences i feel that its best used when you need to sequence you tasks, the best example being to run your tasks in parallel.Here’s a an example of how you can use a powershell workflow to automate VM provisioning using Hyper-V cmdlets and Failover Cluster Cmdlets using differential disks.

To start off i need a csv file which contains the list of VM’s which i need to be created along with their specs (VMName,Memory,VMPath,Hyper-V Host Name, Virtual Switch Name).

So here you can see that im creating 9 VM’s with above specs.

Also note in PSv3 i don’t need to import my modules anymore, powershell does it by itself and all cmdlets are exposed.

workflow Create-VMS
{
# Import the list of VM's from csv file
$vminfo = Import-Csv -path C:Virtualmachines.csv
# Using Foreach loop in parallel to start each thread in parallel

Foreach -parallel  ($vm in $vminfo)
{

$VMName = $vm.VMName
[int64]$Memory = $vm.Memory   
$Vmpath     = $vm.VMpath
$HyperV_Host = $vm.'HyperV_host'    
$VMSwitchName = $vm.VMSwitchName

# Create VHD's based on Differencing disk
New-VHD -Path "$Vmpath$VMName$VMName.vhdx" -ParentPath "C:ClusterStorageVolume1win2012-fixed-diff.vhdx" -Differencing

# Create VM based on parameters obtained from csv file
New-VM -Path "$Vmpath$VMName" -Name $VMName -VHDPath "$Vmpath$VMName$VMName.vhdx" -MemoryStartupBytes ([int64]$memory*1024*1024*1024) -ComputerName $HyperV_Host

# Connecting the Virtual Switch to the VM
Connect-VMNetworkAdapter -VMName $VMName -SwitchName $VMSwitchName  -ComputerName $HyperV_Host

# Make the VM highly available by adding it as clustered resource
Add-ClusterVirtualMachineRole -VirtualMachine $VMName

# Power On the VM
Start-VM $VMName -ComputerName $HyperV_Host

}

}