Capturing CPU Trends with PowerCLI

Inspired by the creeping CPU that we see in Linux guests and helped greatly by @BoerLowie at his blog, I’ve come up with a little PowerCLI to capture CPU trends of the top consumers per cluster.
This is my first cut and will likely see changes over time, like any script should. HTML output and emailed results are the most likely candidates.
The script should be fairly self-explanatory. For each cluster, traverse all VMs and get their OverallCpuUsage (the number that you see in the vSphere Client when selecting a cluster and then the Virtual Machines tab).  Take the top X consumers based on that number and get their average CPU usage performance statistic for N days back in time and compare it to today’s.
The output looks something like this:



So here you go:

#

#  Produce guest CPU trending from a time period back versus a shorter 

#  more immediate time frame.  e.g. 30 days ago versus past 2 days.

#

param(

    [string] $vCenter

)

$DaysOld = -30        # compare to full day stats this many days back

$DaysRecent = -1    # get stats for this many recent days.

$GetTop = 10        # look at top x CPU consumers

Add-PSSnapin VMware.VimAutomation.Core -ErrorAction SilentlyContinue

#if ($vCenter -eq "") {

#    $vCenter = Read-Host "VI Server: "

#}

#if ($DefaultVIServers.Count) {

#    Disconnect-VIServer -Server * -Force -Confirm:$false

#}

#Connect-VIServer $vCenter

$AllClusters = Get-Cluster

Foreach ($Cluster in $AllClusters) {

    Write-Host "`n$($Cluster.Name)"

    $VMs = Get-Cluster $Cluster | Get-VM | `

        Where-Object { $_.PowerState -eq "PoweredOn" }

    $NumVMs = $VMs.Count

    # Get the Overall CPU Usage for each VM in the cluster.  Then cap that 

    # list at the top $GetTop highest for Overall CPU Usage

    $vm_list = @()

    $Count = 0

    Foreach ($vm in $VMs)

    {

        $Count += 1

        Write-Progress -Activity "Getting VM views" -Status "Progress:" `

            -PercentComplete ($Count / $NumVMs * 100)

        # the vSphere .Net view object has the OverallCpuUsage 

        # (VirtualMachineQuickStats)

        # http://www.vmware.com/support/developer/vc-sdk/visdk400pubs/ReferenceGuide/vim.vm.Summary.QuickStats.html

        $view = Get-View $vm

        $objOutput = "" | Select-Object VMName, CpuMhz

        $objOutput.VMName = $view.Name

        $objOutput.CpuMhz = $view.Summary.QuickStats.OverallCpuUsage

        $vm_list += $objOutput

    }

    # Reduce to our Top X

    $vm_list = $vm_list | sort-object CpuMhz -Descending | select -First $GetTop 

    #

    # For each of those VMs, get the statistics for past and current CPU usage

    $NumVMs = $vm_list.Count

    $Out_List = @()

    $Count = 0

    Foreach ($vm in $vm_list)

    {

        $Count += 1

        Write-Progress -Activity "Compiling CPU stats" -Status "Progress:" `

            -PercentComplete ($Count / $NumVMs * 100)

           [Double] $ldblPerfAged = (Get-Stat -Entity $vm.VMName -Stat cpu.usage.average `

            -Start $((Get-Date).AddDays($DaysOld)) `

            -Finish $((Get-Date).AddDays($DaysOld + 1)) -ErrorAction Continue | `

            Measure-Object -Average Value).Average

        If ($ldblPerfAged -gt 0) {

               [Double] $lblPerfNow = (Get-Stat -Entity $vm.VMName -Stat cpu.usage.average `

                -Start $((Get-Date).AddDays($DaysRecent)) `

                -ErrorAction Continue | Measure-Object -Average Value).Average

            [Int] $lintTrend = (($lblPerfNow - $ldblPerfAged) / $ldblPerfAged) * 100

            $objOutput = "" | Select-Object VMName, CpuMhz, PerfAged, PerfNow, Trend

            $objOutput.VMName = $vm.VMName

            $objOutput.CpuMhz = $vm.CpuMhz

            $objOutput.PerfAged = "{0:f2}%" -f $ldblPerfAged

            $objOutput.PerfNow = "{0:f2}%" -f $lblPerfNow

            $objOutput.Trend = "{0}%" -f $lintTrend

            $out_list += $objOutput

        }

    }

    # Spit 'er out

    Write-Host "Top CPU Consumers Trending, $($DaysOld) days vs today`n"

    $out_list | Format-Table -Property VMName, `

        @{Expression={$_.CpuMhz};Name='CPU Mhz';align='right'}, `

        @{Expression={$_.PerfAged};Name='CPU Aged';align='right'}, `

        @{Expression={$_.PerfNow};Name='CPU Now';align='right'}, `

        @{Expression={$_.Trend};Name='Trend';align='right'}

}