Invoke-Command腳本塊從遠程服務器返回變量，但不從本地服務器返回變量

Question

我在這裏做的是生成PRTG在運行腳本時可以解析的XML輸出。該腳本旨在確定最後一次安裝Windows Update的時間。它適用於所有遠程服務器，但當它在本地計算機上運行時，它不會獲得正確的$值。它最終是空的，而不是一個整數。我想我在這裏錯過了一些關於Invoke-Command如何在本地服務器和遠程服務器上工作的東西。有人會介意讓我知道我犯了什麼錯誤嗎？所有的

$ErrorActionPreference = "Stop" 
#Get a list of servers 
$servers = Get-ADComputer -SearchBase 'DC=<removed>,DC=int' -Filter {OperatingSystem -NotLike "Windows Server 2003*"} | Sort Name | Select -ExpandProperty Name 
$value = "" 
#This is the start of the XML output that PRTG will be parsing when the code runs 
Write-Host "<prtg>" 
#Loop through all servers and attempt to get a value for last windows update install. 
foreach($server in $servers) { 
    Write-Host "`t<result>`n`t<channel> $server </channel>" 
    try { 
     Invoke-Command -ComputerName $server -ScriptBlock { 
      $props = @{ 
       LastDetect = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Detect’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       LastInstall = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Install’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       } 
      $stringdato = $props.LastInstall; 
      $DATO = ([datetime]::ParseExact($stringdato, "yyyy-MM-dd HH:mm:ss", $null)) 
      $today = (Get-Date) 
      $timeout = ($today - $DATO) 
      $value = $timeout.Days 
     } 
    } catch { 
     # set value to 999 if there is a problem, for PRTG's error threshold. 
     $value = 999 
    } 
    Write-Host "`t<value>$value</value>" 
    Write-Host "`t<CustomUnit>days</CustomUnit>`n`t<LimitMaxError>90</LimitMaxError>`n`t<LimitMaxWarning>60</LimitMaxWarning>`n`t<LimitMode>1</LimitMode>`n`t</result>`n" 
} 
Write-Host "</prtg>" 

Answer 1

首先，你不應該爲您的本地系統做調用命令。您可以對結果進行驗證。

其次，對於本地調用，您需要將本地系統的IP /主機名添加到本地系統的TrustedHosts列表中，這是沒有意義的。

我一直在你的代碼中使用WMI對象爲的Win32_ComputerSystem驗證應該做要緊。

$ErrorActionPreference = "Stop" 
#Get a list of servers 
$servers = Get-ADComputer -SearchBase 'DC=<removed>,DC=int' -Filter {OperatingSystem -NotLike "Windows Server 2003*"} | Sort Name | Select -ExpandProperty Name 
$value = "" 
#This is the start of the XML output that PRTG will be parsing when the code runs 
Write-Host "<prtg>" 




#Loop through all servers and attempt to get a value for last windows update install. 
foreach($server in $servers) { 
    Write-Host "`t<result>`n`t<channel> $server </channel>" 
    try { 

    $LocalNetwork=Get-WmiObject Win32_Computersystem; 

    ## IF its a local system, then it will go inside IF 
    if($LocalNetwork.Name -eq ($server.trim())) 
       { 


      $props = @{ 
       LastDetect = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Detect’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       LastInstall = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Install’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       } 
      $stringdato = $props.LastInstall; 
      $DATO = ([datetime]::ParseExact($stringdato, "yyyy-MM-dd HH:mm:ss", $null)) 
      $today = (Get-Date) 
      $timeout = ($today - $DATO) 
      $value = $timeout.Days 



       } 
    ## If its a remote system, it will go inside else and will do invoke 
     else { 
     Invoke-Command -ComputerName $server -ScriptBlock { 
      $props = @{ 
       LastDetect = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Detect’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       LastInstall = Get-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\Results\Install’ -Name LastSuccessTime | select -ExpandProperty LastSuccessTime 
       } 
      $stringdato = $props.LastInstall; 
      $DATO = ([datetime]::ParseExact($stringdato, "yyyy-MM-dd HH:mm:ss", $null)) 
      $today = (Get-Date) 
      $timeout = ($today - $DATO) 
      $value = $timeout.Days 
     } 
     } 
    } 

    catch { 
     # set value to 999 if there is a problem, for PRTG's error threshold. 
     $value = 999 
    } 
    Write-Host "`t<value>$value</value>" 
    Write-Host "`t<CustomUnit>days</CustomUnit>`n`t<LimitMaxError>90</LimitMaxError>`n`t<LimitMaxWarning>60</LimitMaxWarning>`n`t<LimitMode>1</LimitMode>`n`t</result>`n" 

} 
Write-Host "</prtg>" 

注：我沒有經歷過的每一步走了，我只是不停地裏的foreach循環驗證。希望能幫助到你。

Answer 2

將$value添加爲Invoke-Command cmdlet的ScriptBlock的最後一條語句。 $value的值應存儲在$result中。我認爲它與PowerShell遠程處理的序列化過程（也許它「自動序列化」分配的最後一個變量）有關。 「通常」，如果你想從PowerShell腳本塊返回一個值，你必須調用像「$ var」這樣的變量。因此$var的內容被髮送到管道中。有關詳細信息，請參閱此thread的答案。

作爲替代你也可以添加以下行到你的腳本：

return $value 

OR：

$value # <----- sent the content of $value down the pipeline 
return 

希望幫助