PeetersOnline

Although I spend quite some time in the Powershell Command Line Interface, the main tool for managing the Virtual Infrastructure remains the VI Client. So wouldn’t it be great if we could somehow show the results of our Powershell VI Toolkit scripts inside the VI Client?
Well, we can! Let’s take a closer look at Custom Fields / Custom Attributes.
If you select either a VMHost (ESX Server) or a VM in the VI Client and open the Summary tab, you will see the Annotations section in the bottom left. When you click Edit, I’m sure you have used the Notes section to enter Descriptions. But have you ever used the Attributes section? Here you can manually add and remove custom attributes and their values. Go ahead and create one. Then select a cluster or datacenter and click the Hosts or Virtual Machines tab. You will notice you can display your custom attribute in this table view, just like all the other properties of your VMs / Hosts. Pretty sweet!
But we don’t want to add and update those fields manually, now do we? Of course not, we’ve got Powershell! Let’s see how we can automate this.
We start by connecting to the Custom Fields Manager:

$VCServerName = “MYVCSERVER”
$VC = Connect-VIServer $VCServerName
$SI = Get-View ServiceInstance
$CFM = Get-View $SI.Content.CustomFieldsManager

Take a look at the $CFM.Field property. It contains an array of available fields. Next step: add our own custom field.

# Variables
$CustomFieldName = “Snapshots”
$ManagedObjectType = “VirtualMachine”
# Check if the custom field already exists
$myCustomField = $CFM.Field | Where {$_.Name -eq $CustomFieldName}
If (!$myCustomField)
{
# Create Custom Field
$FieldCopy = $CFM.Field[0]
$CFM.AddCustomFieldDef($CustomFieldName, $ManagedObjectType, $FieldCopy.FieldDefPrivileges, $FieldCopy.FieldInstancePrivileges)
}

Final step: Fill the custom field with some relevant information:

# Fill Custom Fields
$VMs = Get-VM
$VMViews = $VMs | Get-View
ForEach ($VMView in $VMViews)
{
$SnapshotCount = ($VMView.Snapshot.RootSnapshotList | Measure-Object).Count
If ($SnapShotCount)
{
$VMView.setCustomValue($CustomFieldName,$SnapShotCount)
}
}

Now take a look at the VI Client:

More examples coming soon!
Hugo

PS: Don’t forget to schedule the script to run at an interval, so the values are kept up-to-date!