#######################################################################################
# Copyright Andrew Mitchell 2009
#
# You may freely use and redistribute this script as long as this 
# copyright notice remains intact 
#
#
# DISCLAIMER. THIS SCRIPT IS PROVIDED TO YOU "AS IS" WITHOUT WARRANTIES OR CONDITIONS 
# OF ANY KIND, WHETHER ORAL OR WRITTEN, EXPRESS OR IMPLIED. THE AUTHOR SPECIFICALLY 
# DISCLAIMS ANY IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY, SATISFACTORY 
# QUALITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE. 
#
# Sourced from http://www.yellow-bricks.com/2010/02/24/custom-shares-on-a-resource-pools-scripted
#
# Modified by Doug Youd 20/12/2010 - Added Ability to do multiple clusters, secure 
# credential storage, changed share ratio and fixed a couple of typos.
#
#######################################################################################
############## Modify the following variables to suit your environment  ###############

$vCenterServer = "<FQDN of vCenter Here>"
$CredsLocation = "c:\tmp\Weighted_Shares_Creds.txt"
$User = "Domain\UserName"

# We need to specify the cluster name as the same Resource Pool names might exist within
# multiple clusters
$Clusters = @("cluster 01","Cluster 02")

#All Clusters? (This setting will overide the manual setting above.
$RECURSECLUSTERS = $true #OR $false

# IMPORTANT NOTE
# Only specify resource pools that are in the same level within the resource pool heirarchy.
# Do not specify a combination of parent and child pools.
# These resource pools must already exist within the cluster specified above.
# Specify a comma seperated collection of resource pools
$ResourcePools = @("Gold", "Silver", "Bronze")


#The share values you specify below will be used to determine the weighting of resources available
#to each pool, but will not be the actual share values applied.
$PoolCPUShares = @(50, 35, 15)
$PoolMemShares = @(50, 35, 15)

#Specify the maximum share value we want to apply. The highest priority resource pool will be set 
#to this value. Other pools will be proportionally lower, based on the $PoolCPUShares, $PoolMemshares
#and workloads present within the resource pools
$SharesUpperLimit = 80000

#Specify the minimum share value you want applied to each resource pool. This will ensure that empty 
#resource pools will not end up with zero shares.

$MinPoolCPUshares = 1000
$MinPoolMemShares = 1000


#Do we want the CPU share weighting based on the number of virtual machines within the resource pool, or the number of vCPUs?
#(vCPUs is the default method used by vSphere when specifying Low, Medium or High shares on a per-VM basis)
$CountvCPUs = $true


#######################################################################################
############## Do not modify anything beyond this point  ##############################
#######################################################################################

#load Vmware Module
Add-PSSnapin VMware.VimAutomation.Core

#Get Credentials and store them securely
if(Test-Path $CredsLocation)
{
	$Password = Get-Content $CredsLocation | ConvertTo-SecureString
	$Creds = New-Object System.Management.Automation.PsCredential $User, $Password
}
else
{
	Write-Output "No Cached credentials found in $CredsLocation, Please Enter the Password for username $UserName"
	$Creds = Get-Credential -Credential $User
	$Creds.Password |ConvertFrom-SecureString | Set-Content $CredsLocation
}

Connect-VIServer -server $vCenterServer -Credential $Creds -ErrorAction Stop

#Recurse through all clusters?
if($RECURSECLUSTERS)
{
	#Clear the pre-allocated Servers 
	$Clusters = @()
	foreach($Cluster in Get-Cluster -Server $vCenterServer)
	{
		$Clusters += [string]$Cluster.Name
	}
	Clear-Variable Cluster
}

foreach($Cluster in $Clusters)
{
	$CalcPoolMemShares = @()
	$CalcPoolCPUShares = @()
	$CalcPoolMemShares += $PoolMemShares
	$CalcPoolCPUShares += $PoolCPUShares
	
	$MaxCPUShares = 0
	$MaxMemShares = 0
	$CPUShareMultiplier = 0
	$MemShareMultiplier = 0
	$ArrayIndex = 0
	$NumvCPUs = new-object object[] $ResourcePools.length
	$NumVMs = new-object object[] $ResourcePools.length
	$TotalMemory = new-Object object[] $ResourcePools.length
	$ArrayIndex = 0

	Foreach ($ResourcePool in $ResourcePools)
	{
		$NumvCPUs[$arrayindex] =0
		$NumVMs[$ArrayIndex] =0
		$TotalMemory[$ArrayIndex] = 0
		$pool = Get-ResourcePool -Name $ResourcePool -location $Cluster
		
		Foreach ($VM in ($pool |Get-VM | where {$_.PowerState -eq "PoweredOn"})) #We only care about running VMs
		{
			#Count the number of allocated vCPUs within the Resource Pool
			$NumvCPUs[$arrayindex] += ($VM).NumCpu
			#Count the number of VMs
			$NumVMs[$arrayindex] += 1
			# Count the total memory allocated within the Resource Pool
			$TotalMemory[$ArrayIndex] += ($VM).MemoryMB 
		}
		Write-Host "Discovered " $NumvCPUs[$arrayindex] "running vCPUs in resource pool " $ResourcePool
		Write-Host "Discovered " $NumVMs[$arrayindex] "running virtual machines in resource pool " $ResourcePool
		Write-Host $TotalMemory[$arrayIndex] "MB of memory allocated in resource pool"
		$ArrayIndex += 1		
	}

	#Calculate memory shares
	for ($i=0; $i -lt ($PoolMemShares.length); $i++)
	{
		$CalcPoolMemShares[$i] = [int]$PoolMemShares[$i] * [int]$TotalMemory[$i]	
	}

	#Calculate CPU shares
	#
	#If $CountvCPUs has been defined as true we will base the shares on the number of vCPUs we found in the resource pool. This
	#is the standard mechanism used for CPU share values within VI3 and vSphere and is highly recommmended. Otherwise we will just count
	#number of VMs and ignore the number of vCPUs

	for ($i=0; $i -lt ($PoolCPUShares.length); $i++)
	{	
		if ($CountvCPUs)
		{
			$CalcPoolCPUShares[$i] = [int]$PoolCPUShares[$i] * [int]$numvCPUs[$i]
		}
		else
		{
			$CalcPoolCPUShares[$i] = [int]$PoolCPUShares[$i] * [int]$numVMs[$i]	
		} 
	}
	
	# Find the largest array members so we can set the shares to a sensible value
	$MaxMemShares = $CalcPoolMemShares[0]
	for ($i=0; $i -lt $PoolMemShares.length; $i++)
	{
		if ($CalcPoolMemShares[$i] -gt $MaxMemShares)
		{
			$MaxMemShares = $CalcPoolMemShares[$i]
		}
	}
	
	$MaxCPUShares = $CalcPoolCPUShares[0]
	for ($i=0; $i -lt $CalcPoolCPUShares.length; $i++)
	{
		if ($CalcPoolCPUShares[$i] -gt $MaxCPUShares)
		{
			$MaxCPUShares = $CalcPoolCPUShares[$i]
		}
	}


	If ($MaxCPUShares -gt 0)
	{
		#Set the highest share to a maximum of $SharesUpperLimit. All other shares will be a proprtional value of $SharesUpperLimit
		$CPUShareMultiplier = $SharesUpperLimit / $MaxCPUShares
		
		for ($i=0; $i -lt $PoolCPUShares.length; $i++)
		{
			$CalcPoolCPUShares[$i] = [int]($CalcPoolCPUShares[$i] * $CPUShareMultiplier)
			#If we're below the minimum, readjust
			if ($CalcPoolCPUShares[$i] -lt $MinPoolCPUshares)  { $CalcPoolCPUShares[$i] = $MinPoolCPUshares}
			Write-Host "Resource Pool " $ResourcePools[$i] " : " $CalcPoolCPUShares[$i] " CPU shares"
		}

	}
	else
	{
		Write-Host "Warning: No running VMs found within cluster or CPU shares have been defined as 0 (zero)"
		#Set it to the minimum specified by the user
		for ($i=0; $i -lt $PoolCPUShares.length; $i++)
		{
			$CalcPoolCPUShares[$i] = $MinPoolCPUshares
			Write-Host "Resource Pool " $ResourcePools[$i] " : " $CalcPoolCPUShares[$i] " CPU shares"
		}
	}
	
	if ($MaxMemShares -gt 0) 
	{
		$MemShareMultiplier = $SharesUpperLimit / $MaxMemShares
		for ($i=0; $i -lt $PoolMemShares.length; $i++)
		{
			$CalcPoolMemShares[$i] = [int]($CalcPoolMemShares[$i] * $MemShareMultiplier)
			#If we're below the minimum, readjust
			if ($CalcPoolMemShares[$i] -lt $MinPoolMemshares)
			{ 
				$CalcPoolMemShares[$i] = $MinPoolMemshares
			}
			Write-Host "Resource Pool " $ResourcePools[$i] " : " $CalcPoolMemShares[$i] " memory shares"
		}
	}
	else
	{
		Write-Host "Warning: No running VMs found or Memory shares have been defined as 0 (zero)"
		#Set it to the minimum specified by the user
		for ($i=0; $i -lt $PoolMemShares.length; $i++)
		{
			$CalcPoolMemShares[$i] = $MinPoolMemshares
			Write-Host "Resource Pool " $ResourcePools[$i] " : " $CalcPoolMemShares[$i] " memory shares"
		}
	}

	#Loop through each Resource Pool and set the CPU and memory shares that have been calculated
	$ArrayIndex = 0

	Foreach ($ResourcePool in $ResourcePools)
	{
		$pool = Get-ResourcePool -Name $ResourcePool -location $Cluster
		Set-Resourcepool -Resourcepool $Pool -CPUsharesLevel Custom -NumCpuShares $CalcPoolCPUShares[$ArrayIndex] -MemSharesLevel Custom -NumMemShares $CalcPoolMemShares[$ArrayIndex] 
		$ArrayIndex += 1			
	}
	
	Clear-Variable	CalcPoolMemShares, CalcPoolCPUShares, MaxCPUShares, MaxMemShares, CPUShareMultiplier, MemShareMultiplier, ArrayIndex, NumvCPUs, NumVMs, TotalMemory, i, pool 
	#Next Cluster.
}
disconnect-VIServer -Server $vCenterServer -Force -confirm:$false