Ying Li(MVP) at myITforum.com

Windows PowerShell In "Virtual" Action

In my previous blog, I mentioned that Microsoft Virtulization is script extensible using PowerShell, I didn’t give the full picture. Actually PowerShell is the cornerstone features of System Center Virtual Machine Manager (SCVMM). All functions of the SCVMM Admin Console are built on PowerShell the same way as that Exchange 2007 did. It contains >130 task-oriented Cmdlets which provided a very user approachable scripting experience.

Here is an example:

Get-VM-VMMServer Server1 | Select name, processortype, memory

In case you want to dig deeper, you can find more information at

Windows PowerShell Virtual Machine Manager Cmdlet Reference

Looks like the PowerShell train is left the station and in full speed!

Comparing Window Server(2008) Virtualiztion with VMWare ESX Server

Here is a little chart to compare Microsoft Window Server (2008) Virtualization with VMWare ESX Server

It seems Microsoft has a couple nice features builtin and free of charge. And for powershell lovers Microsoft Virtualization is script extensible using powershell/wmi.

PowerShell script to search "string" in files

Let’s say that you have a log folder contain a lot of log.txt files and you want to find out which log file contain a particular “event” or “string”. The below script can accomplish just that

Get-ChildItem c:\log | select-strings “string”

PowerShell script to selectively kill a process associated with certain "DLL"

Here are some background knowledge- many components of the Windows OS are implemented as what are called “services”. Among them, a fair number of those services are implemented in DLLs rather than in stand-alone executables. But a DLL is only a library of functions that can be called by running porgrams – it can’t be running on its own. Svchost – a standalone program whose job is to execute services that are implemented in DLLs.

At any single time do a get-process svchost on your computer for svchost – you will get a bunch of them

PS C:\PS> get-process svchost

Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessName
-------  ------    -----      ----- -----   ------     -- -----------
     92       4     1744        596    37     0.34    440 svchost
    212       6     3304       1808    61     1.26    648 svchost
    143       4     2892       2132    39     0.59    772 svchost
    490      14     2400       1836    39     2.75   1024 svchost
   1682      72    19044      16596   114    42.83   1356 svchost
    120       3     2588        600    33     0.20   1592 svchost
    101       5     2124       2588    33     0.67   1816 svchost
    289      13     8624       5944    47     0.65   1960 svchost

Now, let’s see we know that wuauserv.dll is running under one of them and for whatever reason we need to stop the svchost process related to wuauserv.dll – how we do that?

$svchosts = get-process svchost
foreach ($process in $svchosts)
{$PModules = $process.modules
foreach ($module in $Pmodules)
{if ($module.modulename -eq "wuauserv.dll")
{$process.id}
}
}

and once you identified the pid – you can do a select “kill”.

Here svchost is just an convenient example, you will run into situations where you have multiple instance whatever.exe running and they all associated with different modules. You could do similar trick here.

PowerShell script to get default gateway for your vpn connection

Here is a powershell script to get the defaultIPGateway information for your vpn connection

$strComputer = "."
$Nics = Get-wmiobject win32_NetworkAdapter -comp $strComputer |where {$_.description -eq "WAN Miniport (IP)"}
foreach ($Nic in $Nics)
{
$Config = Get-Wmiobject win32_NetworkAdapterConfiguration | where {$_.index -eq $Nic.index}
if ($config.IPAddress -ne "$null")
{$VGateway = $config.DefaultIPGateway; $VGateway}
}

PowerShell script to update DNS Search Order on a particular NIC on multiple remote machines

Here is a PowerShell script to update DNS Search Order on a particular NIC on multiple remote machines

$cred = get-credential

$strDNSServers = "192.168.1.50", "192.168.1.51","192.168.1.52"

function Update-DNS
{
$Nic = Get-WMIObject Win32_NetworkAdapter -comp $strComputer |where{$_.NetConnectionID -eq "Local Area Connection"}

$Config   = Get-WMIObject Win32_NetworkAdapterConfiguration -comp $strComputer |where{$_.MACAddress -eq $Nic.MACAddress}

write-host "The current DNS Search Order is:"
$config.DNSServerSearchOrder

$config.SetDNSServerSearchOrder($strDNSServers) | out-null

}

foreach ($strComputer in get-content c:\temp\ServerList.txt)
{
Update-DNS
}

Again you could remove a line or two from above to just check or verify your changes.

PowerShell script to update WINS settings for a particular NIC on multiple remote machines

Here is a PowerShell script to udpate WINS settings on a particular NIC on multple remote machines

#You may need to run this under different user context

$cred = get-credential

Function Update-WINS
{

# Here we target a particular NIC of interest
$Nic = Get-WMIObject Win32_NetworkAdapter -comp $strComputer |where{$_.NetConnectionID -eq "Local Area Connection"}

$Config  = Get-WMIObject Win32_NetworkAdapterConfiguration -comp $strComputer |where{$_.MACAddress -eq $Nic.MACAddress}

$pri = $config.winsprimaryserver
$sec = $config.winsSecondaryServer

Write-host "The Current Primary WINS Server on $strComputer is $pri"
Write-host "The Current Secondary WINS Server on $strComputer is $sec"

$config.SetWinsServer("192.168.1.10","192.168.1.11") |out-null
}

foreach ($strComputer in get-content c:\temp\ServerList.txt)
{
Update-WINS
}

Once you done with the change, you could run the following slightly different script to verify the changes

$cred = get-credential

Function Check-WINS
{
$Nic = Get-WMIObject Win32_NetworkAdapter -comp $strComputer |where{$_.NetConnectionID -eq "Local Area Connection"}

$Config   = Get-WMIObject Win32_NetworkAdapterConfiguration -comp $strComputer |where{$_.MACAddress -eq $Nic.MACAddress}

$pri = $config.winsprimaryserver
$sec = $config.winsSecondaryServer

Write-host "The Current Primary WINS Server on $strComputer is $pri"
Write-host "The Current Secondary WINS Server on $strComputer is $sec"

}

foreach ($strComputer in get-content c:\temp\ServerList.txt)
{
Check-WINS
}

PowerShell script to delete files older than certain days

Here is a PowerShell script to delete files(logs) older than however many days you defined.

BECAREFUL, THIS CAN REALLY DO DAMAGE! USE AT YOUR OWN RISK!

Function GetOldFile
{
 param ($strComputer = $(Read-Host "Please Enter The Server Name")),
       ($Dir = $(Read-host "Please Enter The Directory Path"))
       ($Days = $(Read-Host "How Many Days?"))

 $TargetFolder = "\\" + $strComputer + "\" + $Dir
 
 
 if (Test-Path $TargetFolder)
 {

 #Warn you the targeted folder, so you can double check
  Write-host "The Targeted Folder is:" $TargetFolder -foregroundcolor "Red"
  Write-Host `a `a `a `a `a
  Write-Host "If This Is Not The Intended Target, Press 'Ctrl + C' To Exit" -foregroundcolor "Yellow"
  Start-sleep -s 15

  $Now = Get-Date

 # Notice the minus sign before $days
  $LastWrite = $Now.AddDays(-$days)
  $Files = get-childitem $TargetFolder -include *.log -recurse |Where {$_.LastWriteTime -le "$LastWrite"} 
  foreach ($File in $Files)

 #You can add -whatif to see the consequence – Remove-item $File -Whatif
  {write-host "Deleting File $File" -foregroundcolor "Red"; Remove-Item $File | out-null}
 }
 Else
 {Write-Host "The Folder $TargetFolder Does Not Exist!"}
}
GetOldFile