Using Alternate Credentials with WMI and PowerShell - Take 2 [Hyper-V]

Article
04/26/2010

Last week I did a post about specifying alternate credentials to use with WMI and PowerShell for controlling Hyper-V. Well – thanks to some tips and tricks given to me by my readers – here is a new an improved version:

 # Setup variable for optional commandlet parameters
 $extraParams = @{}
  
 # Setup parameters for prompt to ask if the user wants to use a remote computer
 $message1 = "Do you want to use a remote computer - or the local system?"
 $local = New-Object System.Management.Automation.Host.ChoiceDescription "&Local", "Connect to the local computer."
 $remote = New-Object System.Management.Automation.Host.ChoiceDescription "&Remote", "Connect to a remote computer."
 $options1 = [System.Management.Automation.Host.ChoiceDescription[]]($local, $remote)
  
 # Ask the user if they want to use a remote computer
 $result1 = $host.ui.PromptForChoice($null, $message1, $options1, 0) 
  
 if ($result1 -eq 1)
    {
    # Prompt for the Hyper-V Server to use
    $extraParams["computername"] = Read-Host "Specify the Hyper-V Server to use (enter '.' for the local computer)"
     
    # Setup parameters for prompt to ask if the user wants to use alternative credentials
    $message2 = "Do you want to use alternative user credentials?"
    $yes = New-Object System.Management.Automation.Host.ChoiceDescription "&Yes", "Use alternative user credentials."
    $no = New-Object System.Management.Automation.Host.ChoiceDescription "&No", "Use your current user credentials."
    $options2 = [System.Management.Automation.Host.ChoiceDescription[]]($yes, $no)
  
    # Ask the user if they want to use alternative credentials
    $result2 = $host.ui.PromptForChoice($null, $message2, $options2, 0) 
  
    if ($result2 -eq 0)
       {# Prompt for the user credentials to use
       $extraParams["credential"] = Get-Credential -credential $null
       }
    }
  
 # Get all guest KVP data objects on the server in question, using optional parameters
 $Kvps = gwmi -namespace root\virtualization Msvm_KvpExchangeComponent @extraParams
  
 # Create an empty hashtable
 $table = @{}
  
 # Go over each of the guest KVP data objects
 foreach ($Kvp in [array] $Kvps) 
   {
    # Get the OSName value out of the guest KVP data
    $xml = [xml]($Kvp.GuestIntrinsicExchangeItems | ? {$_ -match "OSName"})
    $entry = $xml.Instance.Property | ?{$_.Name -eq "Data"}
  
    # Filter out unknown operating systems
    if ($entry.Value) {$value = $entry.Value} else {$value = "Unknown"}
  
    # Count up the values and store it in a hashtable
    if ($table.ContainsKey($value)) 
       {$table[$value] = $table[$value] + 1 }
    else
       {$table[$value] = 1}
    }
  
 # Display the results in a nicely formated and sorted manner
 $table.GetEnumerator() | Sort-Object Name | Format-Table -Autosize

There are two key changes:

I now only prompt for alternative credentials if you first indicate that you are connecting to a remote computer.
Optional parameters for the “Get-WMIObject” command are now stored in the $extraParams variable. This is really handy as it means you do not need to special case each call to get a WMI object.

Cheers,
Ben

WhatIsRunning2.zip

Using Alternate Credentials with WMI and PowerShell - Take 2 [Hyper-V]

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