Adding a disk to a VM

Recently I stumbled upon a stubborn vSphere Client at a customer. It just would not let me add a disk a VM. The error message was very generic (and was in the end fixed with a reboot) so I had to find a alternative: Here comes PowerCLI.

The requirements were as follows:

• size of the disk in GB must be specified
• it should be possible to add a new scsi controller if one chooses to do so
• it should be possible to specify which already present scsi controller should be used
• if no option is specified always add the disk to the last scsi controller

It was easy enough to get the script working. One thing I learned was that “new-scsicontroller” requires the VM to be in the “PoweredOff” State.

Update: this script is now published at GitHub.

Here is the script:

<#
.EXAMPLE
PS> Add-DiskToVm.ps1 -vMName reg-belairi81 -vCenter virtualfrogvc.virtual.frog -diskGB 10

This will attach a 10 GB disk to the VM on the last of its scsi controllers
.EXAMPLE
PS> Add-DiskToVm.ps1 -vCenter virtualfrogvc.virtual.frog -vMName reg-belairi81 -diskGB 10 -addController:$true -controllerType paravirtual

This will attach a 10 GB disk to the VM and attach it to a new scsi controller of type paravirtual
.EXAMPLE
PS> Add-DiskToVm.ps1 -vCenter virtualfrogvc.virtual.frog -vMName reg-belairi81 -diskGB 10 -controllerNumber 2

This will attach a 10 GB disk to the VM and attach it to the second controller on the VM
#>

##################################################################################
# Script: Add-DiskToVm.ps1
# Datum: 04.10.2017
# Author: Bechtle Steffen Schweiz AG (c) 2017
# Version: 1.0
# History: Check VMs current set of SCSI Controllers when adding Disks
##################################################################################

[CmdletBinding(SupportsShouldProcess=$true)]
Param(
[parameter()]
[string]$vCenter = "virtualfrogvc.virtual.frog",
# Change to default VM for testing
[string]$vMName = "reg-belairi82",
# Change default Disk Size
[decimal]$diskGB = 2.5,
# Hardcode the SCSI Controller # (like 3 for the third controller)
[int]$controllerNumber = 2000,
# Add new SCSI Controller while you're at it
[boolean]$addController = $false,
# Type of SCSI Controller to add (paravirtual|VirtualLsiLogicSAS)
[string]$controllerType = "paravirtual"

)
function get-scsiCount ($vm)
{
try {
return ($vm | get-scsicontroller -ErrorAction Stop).count
}
catch {
Write-Host "Could not count Scsi Controller of $vm"
exit
}
}

function get-scsiID ($vm, $number)
{
try {
return ($vm |get-scsicontroller |select -skip ($number-1) -first 1).ID
}
catch {
Write-Host "Could not get scsi controller number $number from $vm"
exit
}
}

function get-scsiType ($vm, $id)
{
try {
return ($vm |get-scsicontroller -ID $id -ErrorAction Stop).Type
}
catch {
Write-Host "Could not determine type of SCSI Controller on vm ($vm)"
exit
}
}

function add-DiskToVmOnController ($vm, $controller)
{
try {
New-Harddisk -Controller $controller -CapacityGB $diskGB -VM $vm -Whatif -ErrorAction Stop
} catch {
Write-Host "Could not add disk to VM ($vm)"
exit
}
}

function shutDownVm ($vm)
{
try {
Stop-VMGuest -VM $vm -confirm:$false -ErrorAction Stop
Write-Host "Successfully send the shutdown command over VMware Tools"
}
catch {
Write-Host -Foregroundcolor:red "The VM did not respond to a VMware tools shutdown command"
$switch = Read-Host -Prompt "Would you like to Power off the VM $vm ? (yes/no)"
if ($switch -match "yes") {
Stop-VM -VM $vm -confirm:$false
} else {
Write-Host "You chose not to power off the VM. Stopping the script.."
exit
}
}

while ((get-vm $vMName).PowerState -notmatch "PoweredOff")
{
Write-Host "Waiting for $vm to shut down..."
sleep -s 5
}
$vmHasShutDown = $true
}

####### Main Program ######
try {
Import-Module -Name VMware.VimAutomation.Core -ErrorAction Stop | Out-Null
} catch {
Write-Host "Could not add VMware PowerCLI Modules"
exit
}

try {
Connect-VIServer $vCenter -WarningAction SilentlyContinue -ErrorAction Stop | Out-Null
}
catch {
Write-Host "Could not connect to vCenter $vCenter"
exit
}

Write-Host "Connected to $vCenter. Starting script"

try {
$vm = Get-VM $vMName -ErrorAction Stop
} catch {
Write-Host "Could not find VM with Name $vMName in vCenter $vCenter"
exit
}
if ($addController) {
if ($vm.PowerState -match "PoweredOn") {
Write-Host -Foregroundcolor:red "The VM is still powered On."
$switch = Read-Host -Prompt "Would you like to shut down the VM ($vm)? (yes/no)"
if ($switch -match "yes") {
shutDownVm $vm

} else {
Write-Host "You chose not to shutdown the VM ($vm). Stopping the script now"
exit
}
}
try {
$vm |New-Harddisk -CapacityGB $diskGB |new-scsicontroller -type $controllerType -ErrorAction Stop
if ($vmHasShutDown) {
$switch = Read-Host -Prompt "The VM was shut down for this operation. Power it back on? (yes/no)"
if ($switch -match "yes") {
Start-VM $vm -confirm:$false
}
}
} catch {
Write-Host "could not add scsi controller with new disk to $vm"
exit
}
} elseif ($controllerNumber -ne 2000) {
$numberOfControllers = get-scsiCount $vm
if ($numberOfControllers -gt $controllerNumber) {
Write-Host "You specified controller number $controllerNumber but the VM ($vm) only has $numberOfControllers controllers"
exit
} else {
$scsiID = get-scsiID $vm $controllerNumber
Write-Host "The VM ($vm) has $numberOfControllers SCSI Controller(s) attached. You chose to attach a new disk to the $controllerNumber. adapter"

Write-Host "The VM ($vm) has a "(get-scsiType $vm $scsiID)" Controller for the number you provided"
add-DiskToVmOnController $vm ($vm | get-scsicontroller -ID $scsiID)
Write-Host "Added a disk of $diskGB GB to $vm on controller "($vm | get-scsicontroller -ID $scsiID).Name
}
}
else {
$numberOfControllers = get-scsiCount $vm
$scsiID = get-scsiID $vm $numberOfControllers
Write-Host "The VM ($vm) has $numberOfControllers SCSI Controller(s) attached"

Write-Host "The VM ($vm) has a "(get-scsiType $vm $scsiID)" Controller as the last one"
add-DiskToVmOnController $vm ($vm | get-scsicontroller -ID $scsiID)
Write-Host "Added a disk of $diskGB GB to $vm on controller "($vm | get-scsicontroller -ID $scsiID).Name
}