# Description: Ask a user to answer a question with either yes or no.
 
# Example use: 
# If (Ask-YesOrNo)
# 	{ 
#	# User has confirmed
#	...
#	}
#	Else
#	{
#	# User did not confirm
#	...
#	}
 
Function Ask-YesOrNo
	{
	param([string]$title="Confirm",[string]$message="Are you sure?")
	$choiceYes = New-Object System.Management.Automation.Host.ChoiceDescription "&Yes", "Answer Yes."
	$choiceNo = New-Object System.Management.Automation.Host.ChoiceDescription "&No", "Answer No."
	$options = [System.Management.Automation.Host.ChoiceDescription[]]($choiceYes, $choiceNo)
	$result = $host.ui.PromptForChoice($title, $message, $options, 1)
		switch ($result)
    	{
			0 
			{
			Return $true
			}
 
			1 
			{
			Return $false
			}
		}
	}

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# Function: Translate a VML (e.g.: vml.9364839746917650) to a Lun Path (e.g.: vmhba1:2:137)
 
function Translate-VmlToLunPath
	{
	param(
	[string]$VMHostName,
	[string]$Vml
	)
	Return (Get-VMHost $VMhostName | Get-ScsiLun | Where {$_.ConsoleDeviceName -match $Vml}).CanonicalName
	}

Feed it a host name and a vml string and it will return the lun path. Here’s an example script that uses this function when looking for LUNs with SCSI Reservation Errors:

# Example use in a script: Get LUNs with SCSI Reservation Conflicts
 
$VIServerName = "myVIServer"
$NumLines = 1000
 
$VC = Connect-VIServer $VIServerName
 
ForEach ($VMHost in Get-VMHost)
	{
	ForEach ($Log in ($VMHost | Get-Log -Key vmkernel -NumLines $NumLines))
		{
		$MatchedEntries = $Log.Entries | Where {$_ -match "reservation" -and $_ -match "vml.\d*"}
		ForEach ($VmlId in $matches.values)
			{
			$myObj = "" | Select VMHost, ErrorLun
			$myObj.VMHost = $VMHost.Name
			$myObj.ErrorLun = Translate-VmlToLunPath -VMHostName $VMHost.Name -Vml $VmlId
			Return $myObj
			}
		}
	}
 
Disconnect-VIServer -Confirm:$False

Enjoy!
Hugo

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2. Remove vmware memory limits with Powershell

The attached script contains a function that finds matches for a regular expresion and converts the named matches to object properties. Sounds complex? Take a look at this example for server names:

If you can create the regular expression, this function does the matching and objectizing. It requires no modification at all for working with regular expressions that match other kinds of things, because you name the matching groups inside the regex definition. Cool stuff!

Obj-RegEx (Rename to .ps1)

Enjoy!

Hugo

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48 6F 6C 64 20 66 61 73 74 20 74 6F 20 64 72 65 61 6D 73 A 46 6F 72 20 69 66 20 64 72 65 61 6D 73 20 64 69 65 A 4C 69 66 65 20 69 73 20 61 20 62 72 6F 6B 65 6E 2D 77 69 6E 67 65 64 20 62 69 72 64 A54 68 61 74 20 63 61 6E 6E 6F 74 20 66 6C 79 2E A 48 6F 6C 64 20 66 61 73 74 20 74 6F 20 64 72 65 61 6D 73 A 46 6F 72 20 77 68 65 6E 20 64 72 65 61 6D 73 20 67 6F A 4C 69 66 65 20 69 73 20 61 20 62 61 72 72 65 6E 20 66 69 65 6C 64 A 46 72 6F 7A 65 6E 20 77 69 74 68 20 73 6E 6F 77 2E 20 A A 2D 2D 4C 61 6E 67 73 74 6F 6E 20 48 75 67 68 65 73

Solution:
convert-texttohexandback

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Why do computer nerds mix up Halloween and Christmas? Because 31 OCT = 25 DEC :)

I always mix up the commands used to convert integers to and from decimal, hexadecimal and octal in Powershell. That’s why I wrote these functions and put them in my profile:

# Description: Coverts a decimal into a hexadecimal

function Convert-DECtoHEX
{
param($DEC)
ForEach ($value in $DEC)
{
“{0:x}” -f [Int]$value
}
}

# Description: Coverts a hexadecimal into a decimal

function Convert-HEXtoDEC
{
param($HEX)
ForEach ($value in $HEX)
{
[Convert]::ToInt32($value,16)
}
}

# Description: Coverts an octal into a decimal

function Convert-OCTtoDEC
{
param($OCT)
ForEach ($value in $OCT)
{
[Convert]::ToInt32($value,8)
}
}

Here are some example uses:

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Here are some small functions that can help you determine where the major differences are.

Comparing datastores:

function Compare-VMHostDatastores
{
param([string]$host1,[string]$host2)
$a = Get-VMHost $host1 | Get-Datastore | %{$_.Name}
$b = Get-VMHost $host2 | Get-Datastore | %{$_.Name}
Compare-Object $a $b
}

Compare-VMHostDatastores esxServer1 esxServer2

InputObject                         SideIndicator
———–                                ————-
esxServer1_Local             <=
esxServer2_Local             =>
DATASTORE_TEST1         =>

And comparing Port Groups:

function Compare-VMHostPortgroups
{
param([string]$host1,[string]$host2)
$a = Get-VirtualPortGroup (Get-VMHost $host1) | %{$_.Name}
$b = Get-VirtualPortGroup (Get-VMHost $host2) | %{$_.Name}
Compare-Object $a $b
}

Compare-VMHostPortgroups esxServer1 esxServer2

InputObject                SideIndicator
———–                      ————-
PortGroup_TEST     <=
Internal                       <=

Maybe you prefer to go the other way around and check to which ESX servers a specific datastore is attached?

function Get-DatastoreHosts
{
param([string]$datastore)
Get-VMHost -Datastore (Get-Datastore $datastore) | Sort Name | %{$_.Name}
}

PS D:Scripts> Get-DatastoreHosts DATASTORE_TEST1

esxServer2
esxServer3

Thank Microsoft for Powershell and the Compare-Object cmdlet!

Hugo

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1. Calculate vSphere 5 Licenses with Powershell (UPDATED)
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function CountDown
{
 While ((Get-Date).Year -lt 2009)
 {
  Clear-Host
  Write-Host “COUNTDOWN TO 2009:”
  (Get-Date “1/1/2009 0:00″) – (Get-Date) | Format-Table Days, Hours, Minutes, Seconds -AutoSize
  Write-Host “Countdown brought to you by:”
  Write-Host “http://www.peetersonline.nl”
  Start-Sleep -Seconds 1
 }
 Clear-Host
 Write-Host “HAPPY NEW YEAR!”
 Write-Host “from Hugo at http://www.peetersonline.nl”
}
CountDown

Happy Holidays to all of you!

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Find-Event EventID [Source]
For example: Find-Event 18056
Or: Find-Event 1 MSSQLServer

What it does? Give it a go (it’s harmless)… ;)

Here’s the code:

Function Find-Event
{
param($EventID=”blank”,$Source)
If ($EventID -eq “blank”)
{
Write-Warning “USAGE: Find-Event [-EventID] [[-Source] ]”
}
Else
{
(New-Object -ComObject Shell.Application).Open(“http://www.eventid.net/display.asp?eventID=$EventID&source=$Source”)
}
}

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function Create-Script
{
$ScriptFile = ‘D:\scripts\newscript.ps1′
Remove-Item $ScriptFile -Confirm
ForEach ($i in (Get-History -Count 999))
{
Add-Content $ScriptFile $i.CommandLine
}
Invoke-Item $ScriptFile
}

The function re-uses the same file each time, asking for confirmation to overwrite it. Don’t forget to use Save As… to store your finished work.

I can’t wait to see the masterpieces you will create. Don’t forget to share them!
Hugo

PS: You might want to consider to increase the amount of commands kept in your history. Just set the $MaximumHistoryCount variable to the desired value.

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function Get-Session
{
$Global:SI = Get-View ServiceInstance
$Global:SM = Get-View $SI.Content.SessionManager
Return $SM.SessionList
}

function Stop-Session
{
Process
{
ForEach ($Session in $_)
{
If ($Session.Key -ne $SM.CurrentSession.Key)
{
$Key = $session.Key
$SM.TerminateSession($Key)
Write-Host “Session $Key terminated.”
$Key = $null
}
Else
{
Write-Warning “Cannot terminate current session.”
}
}
}
}

The function Get-Session lists the currently active sessions. You can then filter them as you do any collection of objects in Powershell and pipe them to Stop-Session to have them terminated. Note that VI Client sessions appear to create two actual sessions and that the API (and therefore my function) will not allow you to terminate the current session.
Example:

Get-Session | Where { ((Get-Date) – $_.LastActiveTime).TotalHours -ge 8 } | Stop-Session

Enjoy!

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1. Calculate vSphere 5 Licenses with Powershell (UPDATED)
2. Remove vmware memory limits with Powershell