PS: Using CIM instead of WMI

2 minute read


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


    Cmdlets for Configuring WSMan Session:

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

    (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:

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

    $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.