Recently I was working with vCloud air and PowerCLI and was asked if there was a way to retrieve the statics of a VM and export these to get a better idea of the utilization of that VM.

Working with vCloud Air and the API through the PowerCLI cmdlets I was able to use the GetMetricsCurrent() and GetMetricsHistoric() to retrieve both the current VM Metrics and also the historic metrics of a VM.  The type of metrics and their values is described here.

VM Current Metrics

Current metrics are instantaneous values collected at the time the request is processed. The GetMetricsCurrent() method retrieves a list of current metric values, one for each category. I put this into a handy function which can be found at the end of this post, with this function we can pass vCloud AIR VMs into it and retrieve the current metrics.

VM Historic Metrics

Historic metrics are collected and stored for 14 days. A call to the GetMetricsCurrent() method retrieves the past 24 hours of metric history.  again I created a function that allows us to select a VM (or multiple) and get the historic data for this VM.

You will see that this time the method returns a collection of results in the Sample entry, we can then expand this to return the results for the metric over the last 24 hours.

Creating a VM Statistical report

Of course with this being PowerShell we can add value to these results, I mean who wants to look at a long list of numbers, wouldn’t you rather see a pretty graph?  We can easily use Luc’s great Export-XLSX function to export the results for each metric straight into Excel and even create us a nice graph for each statistic:

The Functions

Make sure you download Lucs Export-Xlsx function from here, and below are the functions I used to retrieve this information from vCloud Air.

Function Get-CIVMMetric {
	Param (
		[Parameter(Mandatory=$True,ValueFromPipeline=$True,ValueFromPipelinebyPropertyName=$True)]
		$CIVM
	)
	Process {
		foreach ($VM in $CIVM) {
			If ($VM.Status -ne "PoweredOn") {
				Write-Host "$VM must be Powered On to retrieve metrics"
				exit
			} Else {
				$Metrics = $CIVM.ExtensionData.GetMetricsCurrent()
				$metrics.Metric
			}
		}
	}
}

Function Get-CIVMHistoricalMetric {
	Param (
		[Parameter(Mandatory=$True,ValueFromPipeline=$True,ValueFromPipelinebyPropertyName=$True)]
		$CIVM
	)
	Process {
		foreach ($VM in $CIVM) {
			If ($VM.Status -ne "PoweredOn") {
				Write-Host "$VM must be Powered On to retrieve metrics"
				exit
			} Else {
				$Metrics = $CIVM.ExtensionData.GetMetricsHistoric()
				$metrics.MetricSeries
			}
		}
	}
}

# Get the Current Metrics for the VM
Get-CIVM sql-w-01a | Get-CIVMMetric

# List the Available Historical Metrics for the VM
Get-CIVM sql-w-01a | Get-CIVMHistoricalMetric

# Get the CPU Historical Metrics
Get-CIVM sql-w-01a | Get-CIVMHistoricalMetric | Where {$_.Name -eq "cpu.usage.average"} | Select -ExpandProperty Sample

$VMName = "sql-w-01a"
Foreach ($stat in (Get-CIVM $VMName | Get-CIVMHistoricalMetric)){
    Foreach ($Entry in $Stat) {
        $Data = $Entry.Sample | Select Timestamp, @{Name=($Entry.Name);Expression={$_.Value}}
        Export-Xlsx $Data C:\Temp\$VMName.xlsx -WorksheetName ($Entry.Name) -ChartType "xlXYScatterSmooth" -AppendWorksheet
    }
}