PS: Using CIM instead of WMI

2 minute read

Description:

So as I’m going through scripts and adding them to my GitHub repo, I’m seeing quite a few of my functions using WMI instead of CIM. So I’m now going through and correcting them.

To Resolve:

  1. WMI => CIM Notes:

    Get-CimInstance => Gets instances of a class.
    New-CimInstance => Creates a new instance of a class.
    Remove-CimInstance => Removes one of more instances of a class.
    Set-CimInstance => Modifies one or more instances of a class.
    Get-CimAssociatedInstance => Gets all the associated instances for a particular instance.
    Invoke-CimMethod => Invokes instance or static method of a class.
    Get-CimClass => Gets class schema of a CIM class.
    Register-CimIndicationEvent => Helps subscribe to events.
    New-CimSession => Creates a CIM Session with local or a remote machine
    Get-CimSession => Gets a list of CIM Sessions that have been made.
    Remove-CimSession => Removes CimSessions that are there on a machine.
    New-CimSessionOption => Creates a set of options that can be used while creating a CIM session.

    Commands = Old => New
    Get-WmiObject => Get-CimInstance
    Get-WmiObject -list => Get-CimClass
    Set-WmiInstance => Set-CimInstance
    Set-WmiInstance –PutType CreateOnly => New-CimInstance
    Remove-WmiObject => Remove-CimInstance
    Invoke-WmiMethod => Invoke-CimMethod

    WSMan:
    Test-WSMan
    Get-WSManInstance
    Set-WSManInstance
    New-WSManInstance
    Remove-WSManInstance
    Invoke-WSManAction

    Cmdlets for Configuring WSMan Session:
    Connect-WSMan
    Disconnect-WSMan
    New-WSManSessionOption
    Set-WSManQuickConfig
    Get-WSManCredSSP
    Enable-WSManCredSSP
    Disable-WSManCredSSP

  2. To find older WMI methods that CIM doesn’t appear to offer (but it does):

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    (Get-CIMClass win32_operatingsystem).CimClassMethods

    For example, this finds the same Win32Shutdown method that WMI has and tells me it needs an argument called “@{ Flags = [int] }”. So from here, I just sub in my $_action variable for my Restart-ComputerWin32 script.

  3. One thing you can place in your scripts is:

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    Try
{
   $Options = New-CimSessionOption -Protocol WSMAN
   $CimSession = New-CimSession -ComputerName $Computer -Credential $Credential -SessionOption $Options -ErrorAction Stop
   Write-Output "Using protocol: WSMAN"
}
Catch
{
   $Options = New-CimSessionOption -Protocol DCOM
   $CimSession = New-CimSession -ComputerName $Computer -Credential $Credential -SessionOption $Options
   Write-Output "Using protocol: DCOM"
}

    This will try and connect to computers using the preferred WSMAN protocol and then, if it fails, go back to DCOM. Then to query specific things, you just build a table:

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    $computerSystem = Get-CimInstance CIM_ComputerSystem -CimSession $CimSession
$computerBIOS = Get-CimInstance CIM_BIOSElement -CimSession $CimSession
$computerOS = Get-CimInstance CIM_OperatingSystem -CimSession $CimSession
$computerCPU = Get-CimInstance CIM_Processor -CimSession $CimSession
$computerHDD = Get-CimInstance Win32_LogicalDisk -Filter "DeviceID = 'C:'" -CimSession $CimSession

$ComputerObject = [Ordered]@{}
$ComputerObject.ComputerName = $computerSystem.Name
$ComputerObject.LastReboot = $computerOS.LastBootUpTime
$ComputerObject.OperatingSystem = $computerOS.OSArchitecture + " " + $computerOS.caption
$ComputerObject.Model = $computerSystem.Model
$ComputerObject.RAM = "{0:N2}" -f [int]($computerSystem.TotalPhysicalMemory / 1GB) + "GB"
$ComputerObject.DiskCapacity = "{0:N2}" -f ($computerHDD.Size / 1GB) + "GB"
$ComputerObject.TotalDiskSpace = "{0:P2}" -f ($computerHDD.FreeSpace / $computerHDD.Size) + " Free (" + "{0:N2}" -f ($computerHDD.FreeSpace / 1GB) + "GB)"
$ComputerObject.CurrentUser = $computerSystem.UserName

$ComputerObjects += $ComputerObject

Remove-CimSession -CimSession $CimSession

    This assumes you are using a foreach loop to loop through multiple computers. The goal is build a table and then display that in the End{} block.

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