Basic VMware Cluster Capacity Check with PowerCLI @ Jonathan Medd's Blog

Basic VMware Cluster Capacity Check with PowerCLI

Posted on January 18th, 2012 Jonathan Medd 8 comments

I recently needed to provide a high level capacity overview per VMware cluster looking at some metrics of interest that were being used as a guide to the capacity state of a cluster. Note: these are by no means definitive or the ones you should be using in your environment, but for these purposes they met the requirements. The metrics I looked at per cluster were the ratio of vCPUs to pCPUs, the amount of Effective, Allocated and average Active Memory and the amount of Free Diskspace.

A couple of things to note:

1.The section below on datastore freespace filters out the local datastore which contains the name of the host.
```
$VMHost = $Cluster | Get-VMHost | Select-Object -Last 1
$HostName = ($VMHost.name -split ".", 0, "simplematch")[0]
$ClusterFreeDiskspaceGB = ($VMHost | Get-Datastore | Where-Object {$_.Name -notmatch $HostName} | Measure-Object -Property FreeSpaceGB -Sum).Sum
```
2. I’ve recently changed the way I create custom objects to output reports with. For a long time I have used the cheat way of Select-Object , partly because of performance and partly because you can’t control the order of properties in New-Object. These are being addressed in PowerShell v3 (see here and here) so I thought it was about time to make the switch. This means for the time being that when working with the output you need to pipe it to Select-Object to control the order of the output, e.g.

Get-Cluster | Get-ClusterCapacityCheck | Select-Object Cluster,ClusterCPUCores,ClusterAllocatedvCPUs,ClustervCPUpCPURatio,ClusterEffectiveMemoryGB,

ClusterAllocatedMemoryGB,ClusterActiveMemoryPercentage,ClusterFreeDiskspaceGB
```
function Get-ClusterCapacityCheck {
<#
.SYNOPSIS
Retrieves basic capacity info for VMware clusters

.DESCRIPTION
Retrieves basic capacity info for VMware clusters

.PARAMETER  ClusterName
Name of the computer to test the services for

.EXAMPLE
PS C:\> Get-ClusterCapacityCheck -ClusterName Cluster01

.EXAMPLE
PS C:\> Get-Cluster | Get-ClusterCapacityCheck

.NOTES
Author: Jonathan Medd
Date: 18/01/2012
#>

[CmdletBinding()]
param(
[Parameter(Position=0,Mandatory=$true,HelpMessage="Name of the cluster to test",
ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$true)]
[System.String]
$ClusterName
)

begin {
$Finish = (Get-Date -Hour 0 -Minute 0 -Second 0)
$Start = $Finish.AddDays(-1).AddSeconds(1)

New-VIProperty -Name FreeSpaceGB -ObjectType Datastore -Value {
param($ds)
[Math]::Round($ds.FreeSpaceMb/1KB,0)
} -Force

}

process {

$Cluster = Get-Cluster $ClusterName

$ClusterCPUCores = $Cluster.ExtensionData.Summary.NumCpuCores
$ClusterEffectiveMemoryGB = [math]::round(($Cluster.ExtensionData.Summary.EffectiveMemory / 1KB),0)

$ClusterVMs = $Cluster | Get-VM

$ClusterAllocatedvCPUs = ($ClusterVMs | Measure-Object -Property NumCPu -Sum).Sum
$ClusterAllocatedMemoryGB = [math]::round(($ClusterVMs | Measure-Object -Property MemoryMB -Sum).Sum / 1KB)

$ClustervCPUpCPURatio = [math]::round($ClusterAllocatedvCPUs / $ClusterCPUCores,2)
$ClusterActiveMemoryPercentage = [math]::round(($Cluster | Get-Stat -Stat mem.usage.average -Start $Start -Finish $Finish | Measure-Object -Property Value -Average).Average,0)

$VMHost = $Cluster | Get-VMHost | Select-Object -Last 1
$ClusterFreeDiskspaceGB = ($VMHost | Get-Datastore | Where-Object {$_.Extensiondata.Summary.MultipleHostAccess -eq $True} | Measure-Object -Property FreeSpaceGB -Sum).Sum

New-Object -TypeName PSObject -Property @{
Cluster = $Cluster.Name
ClusterCPUCores = $ClusterCPUCores
ClusterAllocatedvCPUs = $ClusterAllocatedvCPUs
ClustervCPUpCPURatio = $ClustervCPUpCPURatio
ClusterEffectiveMemoryGB = $ClusterEffectiveMemoryGB
ClusterAllocatedMemoryGB = $ClusterAllocatedMemoryGB
ClusterActiveMemoryPercentage = $ClusterActiveMemoryPercentage
ClusterFreeDiskspaceGB = $ClusterFreeDiskspaceGB
}
}
}
```
powercli, powershell, vmware powercli, powershell, vmware
5 responses to “Basic VMware Cluster Capacity Check with PowerCLI”
- Josh Atwell January 18th, 2012 at 18:09
  
  Nice Script Jonathan! I am looking forward to trying it out in our environment. I would like to point out that I have trouble with the hostname being included on local datastores in parts of our environment. While I created a function to update those (I should post this out sometime) it has not been run everywhere yet. As such, I use the following for identifying local datastores:
  
  Get-Datastore | Where {$_.Extensiondata.Summary.MultipleHostAccess -eq $False}
  
  So far I have not run into any issues with this.
- Jonathan Medd January 18th, 2012 at 21:01
  
  Nice one, cheers for that. I knew there was a better way to get the local datastores, but it had slipped my mind. Script updated
  
  To exclude local datastores…..
  
  Get-Datastore | Where-Object {$_.Extensiondata.Summary.MultipleHostAccess -eq $True}
- Sean Duffy January 18th, 2012 at 21:39
  
  Hi Jonathan,
  
  Great function – it returns some very useful information. I have added this one to my PS profile. You have also inspired me to go back and write a function of my own that would be useful in my day-to-day tasks at the office.
  
  I often write scripts that report on useful information, but I don’t often do full functions that can utilise the pipeline or accept parameters. I think this will be good practise for me.
  
  Cheers,
  Sean
- Josh Atwell January 19th, 2012 at 00:15
  
  NP. I probably got it from Luc at some point
- chad King February 17th, 2012 at 16:17
  
  It would be cool if it had CPU MHz Capacity and usage as well. The other metrics are really good to know.
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