Bulk unregister / register VMs on vSphere

If you want to unregister all VMs on a particular vSphere Cluster / Host you’re pretty done using the GUI, registering all VMs on a datastore could take you to the “hell of clicking masters” depending on the amount of VMs to register. I created two powershell functions which do that stuff for you.

Usage:

Function unregisterallvm([STRING]$datacentername,[STRING]$clustername)
{
 $vms = Get-DataCenter $datacentername | Get-Cluster $clustername | get-vm
 Foreach ($vm in $vms)
 {
   $vmname = $vm.name
   Write-Host "Unregistering VM: $vmname from Cluster $clustername"
   Remove-VM -VM $vmname -DeleteFromDisk:$false -Confirm:$false -RunAsync
 }
}

Function registerallvm([STRING]$vCenterHost,[STRING]$datacentername,[STRING]$clustername,[STRING]$datastorename)
{
 $datastore = Get-Datacenter $datacentername | Get-Datastore | ? {$_.name -match $datastorename}
 $datastoreshortname = $datastore.Name
 $ResourcePool = Get-Cluster -Name $clustername | Get-ResourcePool | Get-View
 $vmFolder = Get-View (Get-Datacenter -Name $datacentername | Get-Folder -Name "vm").id
 $vmdirs = (dir "vmstores:\$vCenterHost@443\$datacentername\$datastoreshortname\")
 Foreach ($f in $vmdirs)
 {
   $vmname = $f.Name
   $checkreg = (Get-Cluster $clustername | Get-VM | ? { $_.name -match $vmname})
   If (!$checkreg)
   {
     "Registering VM: $vmname on: $clustername \ $datastoreshortname"
     $vmFolder.RegisterVM_Task("[$datastoreshortname]/$vmname/$vmname.vmx", $vmname, $false, $ResourcePool.MoRef, $null)   
   }
   Else
   {
     "VM: $vmname is already registered with the same name. Skipping...."
   }
 }
}

Of course you need to place this functions in your script before you’re calling them and you need PowerCLI snapin registered and have a connection to vCenter using:

connect-viserver -server "vcenter.domain.com"