Update – The Mighty Jeff Hicks (JeffHicks on Twitter) wrote in to call me out on not using the proper verb-noun Powershell naming standard for my functions. The script has been updated to fix this mistake. Thanks Jeff!

In larger environments adding new LUNs to VMWare can be tedious and messy. This is especially true if you have multiple Virtual Centers connected to the same SAN(s). Say, for example, that you have a corporate naming standard for your Datastores like the following:

IBM_Tier3_01

That’s SAN manufacturer, Tier level, and then a unique number. This is, in my experience, a pretty standard naming scheme. As the environment grows keeping track of those unique incremental numbers at the end and ensuring you are using the next one in line can be a bit annoying. If you have more than one Virtual Center then there is a real risk that you will re-use the same number twice. Say you have this scenario:

You have to vCenters: Cluster1 anc Cluster2. On Cluster1 the most recent Tier 1 datastore is named IBM_Tier1_21. On Cluster2 the most recent Tier 1 datastore is named IBM_Tier1_22. You need to add a new tier 1 Datastore to Cluster1 so you connect to the Cluster1 Vcenter, look at your current Tier1 Datastores and add one to the last Datastore in the list. If you forget to look at Cluster 2 first then you will be creating another IBM_Tier1_22 datastore. This calls for some automation…

The below PowerCLI script is useful for adding new Datastores in environment of one or more Virtual Centers. It performs the following operations:

1. Connects to all Virtual Centers in your environment (Defined in the $VCenters array)
2. Scans HBAs looking for new LUNs
3. Asks the user what Tier storage the new Datastore should be part of
4. Retrieves a list of all existing Datastores in that tier across all Virtual Centers and displays them to the user while suggesting the next datastore in line. It will not allow the user to re-use an existing store name.
5. Generates the new Datastore name based on the company’s naming standards
6. Displays a list of all LUNs presented to the VMWare environment which are available for being converted to a VMFS for the user to select
7. Asks the user for what block size to use for the new datastore
8. Displays the information for the new datastore to the user for confirmation and allows them to choose to continue with creation or not.
9. Adds the new datastore!

I’ve tried to make this script easy to customize for various environments. The following settings at the top of the script will need to be modified for your environment.

• $credFolder – Location of your stored credentials for your Virtual Center(s). This is necessary if you are not launching PowerCLI with a user account that has permission to sign on to Virtual Center. The script assumes that the filename for your credentials file is the name of the cluster, but this could be easily modified. If you do not specify this credential you will simply be prompted at the start of the script’s execution for your login information. See Storing your vCenter Credentials for instructions on creating a file containing your Virtual Center credentials
• $tierNamePrefix & $tierNameSuffix – These variables are used to define your datastore naming standard. $tierNamePrefix is what will precede the Tier number and $tierNameSuffix is what will follow the Tier number and precede the Datastore’s unique number.
• $vCenters – Array containing the host names of your Virtual Centers. If you only have one Virtual Center then simply specify that single Virtual Center. If you have more than one then add them all within quotes and comma separated.
• $storageTiers – Array containing your storage Tier numbers. In most environments this is 1 – 3.

Additionally in the createNewDatastore function you can change the commenting on the New-Datastore commands to cause the script to not actually create the datastores for testing purposes.

Here’s the script… It is a fairly long one, but don’t let it intimidate you!

<####################################################################
newLUNAdder.ps1

 Automates the process of adding new LUNs to the VMWare clusters
 and provides datastore naming mechanism that helps to prevent overlapping names
 between the two clusters.

####################################################################>

#########################################
# GLOBALS

# Location of secure VMWare credentials file
# Script assumes that the file name for the login
# information is the same as the vcenter name as
# specified in the $vCenters array.
# Script will prompt for login information
# if location does not exist
$credFolder = "C:\VMWare\creds\"

# Prefix and suffix for the datastore names.  Datastore names
# will be built in the following format:
#
# tierNamePrevfix tierNumber tierNameSuffix volumeNumber
#
# For Example:
#
# SVC_Tier3_vStore42
#
# Where:
# tierNamePrefix = SVC_Tier
# tierNumber = 3
# tierNameSuffix = _vStore
# volumeNumber = 42
$tierNamePrefix = "SVC_Tier"
$tierNameSuffix = "_vStore"

# VCenters in the environment - Add or Subtract as appropriate
$vCenters = "cluster1","cluster2"

# Storage tiers, using the very typical 1, 2, 3..
$storageTiers = "1", "2", "3"

# Initialize global variables

$workingCluster
$workingHost
$workingDatastore
$workingTier
$workingStoreName
$totalVMHosts
$workingBlockSize

$physicalHosts = @();

# Datastore block sizes
$blockSize = @(("1", "2", "4", "8"),("256", "512", "1024", "2048"))

# Get the current VIServerMode setting so that we can set it back when the script ends
$defaultVIServerMode = Get-PowerCLIConfiguration
# Set mode to multiple
Set-PowerCLIConfiguration -DefaultVIServerMode multiple -Confirm:$false

clear-host
#########################################

# Functions

function Get-Cluster() {
	# Asks user which cluster to add the new datastore to.

	# Generate Menu

	$menuTest = $false
	do
	{
		clear-host
		$i = 0
		foreach ($vcenter in $vcenters) {
			Write-Custom "($i) $vcenter" "select"
			$i++
		}
		Write-Host ""
		$input = Read-Host "Which Cluster Would You Like to Add Storage To?" 

		# Check if the input is a number and less than $i
		if ($input -match '^\d+$' -and $input -lt $i) {
			set-variable -name workingCluster -value $vcenters[$input] -scope Global

			$menuTest = $true
		}
	} until ($menuTest -eq $true)
}

function Count-Hosts() {
	# Counts the total number of hosts across all clusters.  This is done for
	# for progess counters

	write-custom "Determining the total number of hosts across all clusters..." "info"

	$temphosts = get-vmhost
	$tempCount = $tempHosts.count

	set-variable -name totalVMHosts -value $tempCount -Scope Global
}

function Get-Host() {
	# Asks user which VMWare Host in the chosen cluster to use for initally adding the
	# new storage.  List of VMS is generated based on choice made in Get-Cluster

	# Get list of physical hosts in the cluster
	$physicalHosts = get-vmhost | where {$_.Uid -like "*$workingCluster*"} | select name | sort name

	$menuTest = $false

	# Generate Menu to display hosts
	do
	{
		[int]$i=0
		clear-host
		foreach ($physHost in $physicalHosts) {
			$hostname = $physHost.name
			write-Custom "($i) $hostname" "select"
			$i++
		}
		write-host "Working cluster $workingcluster"
		$input = Read-Host "Please select a physical host to map the datastore to first"

		# Convert $input to an integer in order to use the value in the $physicalHosts array
		$convInput = [int]$input

		if ($convInput -gt -1 -AND $convInput -lt $i) {

			# Set the workingHost variable to the chosen host globally
			set-variable -name workingHost -value $physicalHosts[$convInput].name -scope Global
			$menuTest = $true # Break out of loop on valid selection
		}

	} until ($menuTest -eq $true)
}

Function Scan-HBAs {
	# Scans HBAs on all hosts across all clusters

	$j = 0
	$totalHosts = get-vmhost

	foreach ($vm in get-vmhost) {
		$j++
		write-progress -id 1 -activity "Rescanning HBAs across all clusters" -Status "Percent Complete: " -PercentComplete (($j / $totalVMHosts) * 100)
		get-vmhoststorage -vmhost $vm.name -RescanAllHba
		clear-host
	}

	clear-host

	# Remove progress indicators
	write-progress -id 1 "Rescanning HBAs" "Complete" -Completed
}

Function write-custom ($msg, $type) {
	# Writes out using custom settings

	if ($type -eq "info") {
		write-host $msg -foregroundcolor black -backgroundcolor yellow
	}
	if ($type -eq "select") {
		write-host $msg -backgroundcolor darkgreen -foregroundcolor white
	}

}

function Get-StorageTier {
	# Lists standard tiers of storage and asks user to select
	# the appropriate tier for the new datastore.  This will be used to decide
	# the new name for the datastore

	$menutest = $false

	do {
		[int]$i = 0
		clear-host
		foreach ($tier in $storageTiers) {
			write-custom "($i) Tier: $tier" "select"
			$i++
		}

		$input = Read-Host "What is the tier of this new storage"

		$convInput = [int]$input

		if ($convInput -gt -1 -and $convInput -lt $i) {
			set-variable -name workingTier -value $storageTiers[$convInput] -scope Global

			$menutest = $true
		}
	}  until ($menutest -eq $true)
}

function Get-BlockSize {
	# Lists available block sizes for the new datastore and asks user to select
	# the desired size

	$menutest = $false

	do {
		clear-host

		# Loop through the array and display the block size options
		for ($i=0; $i -lt $blocksize[0].length; $i++) {
			$j = ($i + 1)

			# Select the values from the multidimensional array
			$blockSizeMB = $blocksize[0][$i]
			$maxFileSize = $blocksize[1][$i]
			write-custom "($i) Blocksize $blockSizeMB MB (Max file size $maxFileSize GB)" "select"
		}
		$input = read-host "What block size would you like to set for this new datastore"

		$convInput = [int]$input

		# Make sure selection is within range
		if ($convInput -gt -1 -and $convInput -lt ($blocksize[0].count)) {
			# Set the workingBlockSize variable to the chosen option
			set-variable -name workingBlockSize -value $blockSize[0][$convInput] -scope Global
			$menutest = $true
		}
	} until ($menutest -eq $true)
}

function Populate-TierArrays {
	# Builds an array containing the store numbers currently in use for the chosen Tier.

	# Build text to search for
	$tierToScan = "*$tierNamePrefix$workingTier*"

	$storeNumber = @();

	# Get the datastores that are part of the chosen tier
	$currentStores = get-datastore | where {$_.name -like $tierToScan} | sort Name

	# Build text to remove from results returned from get-datastore
	$tierText = "$tierNamePrefix$workingTier$tierNameSuffix"

	# Populate array with results
	foreach ($store in $currentStores) {
			$storeNumber += $Store.name.Replace($tierText, "")
	}

	return $storeNumber

}

function Show-CurrentDataStores {
	# Builds a sorted and filtered array of current datastores in the
	# chosen tier across all clusters.  This array is presented to the
	# user in the Name-NewStore function.

	# When creating the number array there will be errors for
	# data stores that do not follow naming convention and end
	# with something other than a number.  We can safely exclude
	# these items from the array.  We set error action to silently
	# continue to avoid ugly error msgs while building the array
	$ErrorActionPreference = "SilentlyContinue"

	# Populate aray numbers from all clusters
	write-custom "Getting List of datastores in selected tier" "info"

	$allStoreNumbers = Populate-TierArrays

	# Filter out duplicate entries
	$allStoreNumbers = $allStoreNumbers | select -uniq

	$intStoreNumber = @();

	# Convert array to integer for better sorting
	foreach ($num in $allStoreNumbers) {
		$intStoreNumber += [int]$num
	}

	# Sort integer array
	[Array]::Sort([array]$intStoreNumber)

	clear-host

	return $intStoreNumber
}

function Name-NewStore {
	# Displays list of current datastores in the chosen tier to the user
	# and asks the user to name the new datastore.  The next available datastore
	# integer is presented as a default option.  Should the user choose their
	# own integer the function will check that the number is not already in
	# use and will continue to prompt the user for a number until they choose
	# one that is available.

	# Build array of current datastores in the chosen tier
	$intStoreNumber = Show-CurrentDataStores

	# Find the last used datastore number and increment it to use as the default
	# new store number
	[int]$nextStoreNumber = ($intStoreNumber[-1] + 1)

	# Display current store numbers to user and request a new one
	$menutest = $false
	do {
		clear-host
		write-custom "Current Tier $workingTier numbers: " "info"
		foreach ($num in $intStoreNumber) {
			write-custom $num "info"
		}
		$input = read-host "Please enter new store number [$nextStoreNumber]"

		if ($input -eq "") {
			# User did not enter a number, use the default
			$input = $nextStoreNumber
			$menutest = $true
		} else {
			# Check to make sure user has not entered a number already in use
			foreach ($num in $intStoreNumber) {
				if ($num.ToString() -like $input) {
					$menutest = $false
					break
				} else {
					$menutest = $true
				}
			}

			if ($menutest) {

				# Build the newStoreName and set it to the global workingStoreName variable

				# I'm going to add a little hidden feature for the admins..  Test if the
				# input from the user is a number.  If so then create the new store name
				# using the standard.  If it isn't, then assume that the admin is breaking
				# the naming standard for a good reason and that they don't want their input
				# added to the naming convention.

				if ($input -match '^\d+$') {
					# it is a number, use the normal naming convention
					$newStoreName = "$tierNamePrefix$workingTier$tierNameSuffix$input"
				} else {
					# user's input contains a string.  Let's make sure they really mean
					# to do this

					$verifyInput = Read-Host "Your input is not a number, do you want to create a non-standard data store name? (y/n) "

					if ($verifyInput -like "y") {
						$newStoreName = $input
					} else {
						# set menutest back to false to repeat the menu
						$menutest = $false
					}
				}
			}
		}
	} until ($menutest -eq $true)

	set-variable -name workingStoreName -value $newStoreName -scope Global
}

function Get-AvailableDatastores {
	# Query chosen cluster to find datastores that are available to have VMFS added.
	# Display list to user for selection

	write-custom "Building list of available datastores..." "info"

	# Build list of available datastores
	$datastore = $null
	$hostView = get-vmhost -name $workingHost | get-view
	$dsView = get-view $hostView.ConfigManager.DatastoreSystem
	$unUsed = $dsView.QueryAvailabledisksForVMFS($datastore)

	$menuTest = $false

	# Generate Menu
	do
	{
		[int]$i=0
		clear-host
		foreach ($store in $unUsed) {
			$storeName = $store.CanonicalName
			write-custom "($i) $storeName" "select"
			$i++
		}
		$input = Read-Host "Please select a datastore to Add"
		$convInput = [int]$input

		# Make sure user selected a valid datastore option. Represent menu if they did not.
		if ($convInput -gt -1 -AND $convInput -lt $i) {

			set-variable -name workingDatastore -value $unUsed[$convInput].CanonicalName -scope Global
			$menuTest = $true
		}

	} until ($menuTest -eq $true)
}

Function Create-NewDatastore {
	# Present selection criteria to the user and make sure they want to move forward
	# with creating the new datastore.  If yes: Do it.  If not: Exit

	$menutest = $false

	do {
		clear-host
		write-custom "Creating new VMFS Datastore using the following criteria:" "info"
		write-custom "Cluster: $workingCluster" "info"
		write-custom "Host: $workingHost" "info"
		write-custom "Store: $workingDatastore" "info"
		Write-custom "Tier Level: $workingTier" "info"
		Write-custom "Block Size: $workingBlockSize" "info"
		Write-custom "New Store name: $workingStoreName" "info"
		$input = read-Host "Do you wish to continue (y/n)"

		if ($input -like "n") {
			# User chose not to create the datastore.  Return $input to the main program
			# and exit function
			return $input
		}

		if ($input -like "y") {
			$menutest = $true
		}

	} until ($menutest -eq $true)

	clear-host

	write-custom "Creating Datastore $workingstorename..." "info"

	# Create the datastore using the selected criteria.  Comment below line out if you are testing
	New-Datastore -Name $workingStoreName -VMHost $workingHost -Path $workingDatastore -VMFS -BlockSizeMB $workingBlockSize

	# Uncomment below line if you are testing
	#New-Datastore -Name $workingStoreName -VMHost $workingHost -Path $workingDatastore -VMFS -BlockSizeMB $workingBlockSize -WhatIf

	if ($?) {
		clear-host
		write-custom "Datastore Created.  Rescanning across all clusters" "info"
	}

	# Return input so script body will know if the datastore was created.
	return $input

}

Function Connect-VCenter {
	# Connect to the supplied virtual center

	write-custom "Connecting to VMWare environment" "info"

	$Creds = ""

	Foreach ($vcenter in $vcenters) {
		$Creds = $credFolder += $vcenter
		Connect-VIServer $vcenter -User $Creds.User -Password $Creds.Password
	}
}

######################################
# Main Script Body

#	Script launches each step of the add storage process via
#	sequential functions

# Connect to our VCenter(s)
Connect-VCenter
clear-host

# Get a count of all physical hosts across all clusters
Count-Hosts
clear-host

# Rescan HBAs so as to make sure VMWare is aware of new available datastores
Scan-HBAs

# Loop to allow user to add multiple new luns without having
# to restart the script and rescan HBAs each time
$input = "y"
do {
	clear-host

	# Determine which cluster to add the new datastore to
	Get-Cluster
	clear-host

	# Determine which host to initially add the datastore to.  This is required
	# for the new-datastore command
	Get-Host
	clear-host

	# Find available datastores that are eligible for VMFS
	Get-AvailableDatastores
	clear-host

	# Determine which tier this datastore should be a member of
	Get-StorageTier
	clear-host

	# Determine which block size to use with the new datastore
	Get-BlockSize
	clear-host

	# Build list of current datastore numbers in the chosen tier and determine
	# what the new store should be named
	Name-NewStore
	clear-host

	# Show user final selections and confirm the add storage operation.  Add the
	# storage if the user chooses yes
	$payload = Create-NewDatastore
	clear-host

	if ($payload -like "y") {
		write-custom "The new datastore has been added..." "info"
	}

	$input = read-Host "Would you like to add another LUN? (y/n)"
} until ($input -eq "n")

# Set VIServerMode back to where it was when we started
Set-PowerCLIConfiguration -DefaultVIServerMode $defaultVIServerMode.defaultVIServerMode -Confirm:$false