E-Guide

Expert Insight into PowerShell’s

Scripting

PowerShell offers new users the ability to quickly learn how to carry

out common administration tasks with the basic PowerShell cmdlets.

In this e-guide from SearchWindowsServer.com, discover the

numerous benefits of implementing Microsoft PowerShell. Learn about

the several ways to manage Hyper-V with PowerShell. Plus discover

different approaches in scripting and aspects of virtualization

management.

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E-Guide

Expert Insight into PowerShell’s

Scripting

Table of Contents

Scripting: VMware PowerCLI vs. Microsoft PowerShell

Using PowerShell to manage Microsoft Hyper-V

Resources from Dell Compellent

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Scripting: VMware PowerCLI vs. Microsoft PowerShell

By Mike Laverick, Contributor

It may seem unlikely to compare VMware PowerCLI and Microsoft PowerShell, because the

former requires the latter to be installed first and is merely a vendor-specific addition to the

core PowerShell environment.

It's also unlikely that someone would pick a virtualization platform merely based on its

scripting capabilities. So rather than setting up a grudge match pitting one company against

another, I will tell you what I like and dislike about each implementation. Hopefully, I can

explain how both companies can improve their respective scripting offerings. Let's start with

Microsoft.

Microsoft PowerShell

One aspect of virtualization management I like about Microsoft SCVMM is its built-in View

Script window. This acts like a script recorder that gives you the ability to capture

administrative actions as PowerShell scripts. A good example of this is when you are

carrying out a migration task within SCVMM in order to move a VM to another Hyper-V host.

At the end of the wizard a "View Script" button will display, showing the exact PowerShell

commands needed in a script.

Figure 1

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In part, this is simply a happy fortune that comes from the way SCVMM was developed.

Initially, SCVMM was designed to be managed by PowerShell, and then later a graphic

management shell was developed around it so Windows admins didn't need to learn the

PowerShell behind it.

It isn't difficult for Microsoft to expose the underlying PowerShell executing in the

background. This won't help admins write PowerShell scripts with variables for each loop,

error checking and logging, but it is very useful to folks who are new to PowerShell and at

least gets them over the hump of learning how to carry out common administration tasks

with the basic PowerShell cmdlets.

Today, Hyper-V doesn't have an official set of cmdlets, but a set was built by James O'Neill

and is stored on Codeplex website. O'Neill took the APIs and wrote his cmdlets based on

this. With the release of SCVMM 2012, the number of cmdlets is going to increase

significantly, as the amount of tasks one can do in SCVMM in general is increasing

substantially.

VMwarePowerCLI

VMware has made great strides with a number of new features to PowerShell, which it calls

PowerCLI. In successive releases the company has significantly upped the number of

cmdlets in the product to nearly 250. Earlier additions lacked cmdlets to control the ESX

host iSCSI stack although the recent vSphere4.1 release has plugged that gap.

There are still the odd holes here and there. For instance, there aren't any meaningful

cmdlets around VMware's Distributed vSwitches. Although its fair to say that PowerCLI 4.1

did update cmdlets which allow the administrator report information about an existing

DvSwitch configuration including enhancements to the following cmdlets:

Get-VirtualSwitch

Get-VMHost

Get-VM

Get-VMHostNetworkAdapter

New-NetworkAdapter, Set-NetworkAdapter

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It appears the company favors its "Host Profiles" feature as the main configuration tool for

newly created ESX hosts. Customers who buy the Enterprise and SKU qualify for both

Distributed vSwitches and Host Profiles.

There are new deployment methods coming in future releases which emphasize the use of

host profiles over PowerCLI for deployment of new ESX hosts. It's worth mentioning that

vExpert Luc Dekens has developed his own functions that allow for management of

DvSwitches. With that said, the primary use of PowerCLI in the VMware Community is

reporting and checking the vSphere environment. Scripts such as virtu-al.net "Health

Check" also have been extremely popular.

For everything else there is the VMware SDK. This extremely rich interface allows access to

practically every action one may want to carry out, both at the host and the vCenter

management server. This is in contrast to Microsoft where the only officially supported

cmdlets are to SCVMM. There is some similarity between VMware and Microsoft there: both

offer very limited PowerShell support for the so-called "free" editions of their hypervisors.

Both companies are wary that customers could get a hypervisor for free, and manage it with

command-line tools rather than paying a premium for the management piece.

The vCenter itself lacks the integration of PowerCLI directly in the vSphere Client. In

searching for some way of "recording" administration as PowerCLI code, one could look at

VMware Onyx, which is a free appliance that sits between the vSphere Client and vCenter

and outputs the actions as raw PowerCLI SDK code. As a side note, it also outputs actions in

a JavaScript format suitable for VMware's Orchestrator, a technology sadly underused by

most VMware admins.

The output from Onyx a might be a bit overwhelming but don' be intimidated. There are

more friendly ways of carrying out administration tasks via a GUI, as well as collecting the

PowerCLI code after the task is completed. One should play around with the PowerGUI front

end and its various PowerPacks that extend its functionality. PowerGUI works with a vast

array of administration tasks including Active Directory, but from a virtualization perspective

there are PowerPacks for VMware vSphere, Citrix XenServer, Microsoft HyperV, Virtual Disk

Analysis, HP Virtual Connect and Quest vWorkspace.

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Figure 2

In the meantime, VMware is attempting to extend PowerCLI support to its other

technologies, which is something that Microsoft is already down the road on. There is a

PowerCLI for VMware virtual desktop solution, called View, but the implementation is very

different from that of vSphere PowerCLI. It has a feeling more akin to a DOS command-line

system than PowerShell and allows for pipelining and querying objects for their properties

and attributes. As of now technologies like VMware Site Recovery Manager do not have

PowerCLI, but it is likely on VMware's radar screen.

For the benefit of those folks not living in the Windows world, PowerShell and PowerCLI

have sent shockwaves through the system administration world. But there are Linux-based

scripters who may feel left out in the cold. VMware offers Perl and Microsoft does not, but

that is to be expected.

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These other toolkits aren't gaining much traction in the communities I travel in. Similar

older CLI and remote CLI seem to be withering too such as VMware's port of its "ESX"

commands to the vCLI and vCLI appliance. Right now they feel like an intermediary step

intended to wean VMware customers off their dependency on the old "Service Console"

environment. Right now it feels like PowerShell and PowerCLI will rule the sysadmin's roost

for the foreseeable future.

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Using PowerShell to manage Microsoft Hyper-V

By Brandon Shell, Contributor

Many admins use PowerShell to automate components like user creation and folder

permissions, but virtualization technologies can also be managed from the command line,

including Microsoft Hyper-V.

While there are several ways to manage Hyper-V with PowerShell, this article will focus on

the free approaches using Windows Management Instrumentation (WMI) scripting and an

open source tool from CodePlex.

Before using WMI scripting to manage Hyper-V, it’s important to understand what classes

are available. Microsoft’s list includes a significant number of classes and while is fairly

complete, they are not necessarily easy to use and are certainly not intuitive. Therefore,

using WMI to manage Hyper-V is not for the faint of heart.

One of the more popular methods for managing Hyper-V with PowerShell is with PowerShell

Management Library for Hyper-V (PSHyperV) a free, open source CodePlex project written

by James O’Neil. This is by far the best free option out there and gives administrators a very

thorough collection of cmdlets that do everything from virtual machine inventory to virtual

network management. Let’s touch on a few of them:

Get-VM -- returns all the virtual machines on a given Hyper-V server (see Figure 1).

Figure 1: Get-VM command

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The following code demonstrates the Get-VM command:

Function Get-VM {# .ExternalHelp MAML-VM.XML param( [parameter(ValueFromPipeLine = $true)] [ValidateNotNullOrEmpty()][Alias("VMName")] $Name = "%",

[parameter()][ValidateNotNullOrEmpty()] $Server = ".", #May need to look for VM(s) on Multiple servers [Switch]$Suspended, [switch]$Running, [switch]$Stopped ) Process { # In case people are used to the * as a wildcard... if ($Name.count -gt 1 ) {[Void]$PSBoundParameters.Remove("Name") ; $Name | ForEach-object {Get-VM -Name $_ @PSBoundParameters}} if ($name -is [String]) { $Name = $Name.Replace("*","%") # Note in V1 the test was for caption like "Virtual%" which did not work in languages other than English. # Thanks to Ronald Beekelaar - we now test for a processID , the host has a null process ID, stopped VMs have an ID of 0.

$WQL = "SELECT * FROM MSVM_ComputerSystem WHERE ElementName LIKE '$Name' AND ProcessID >= 0" if ($Running -or $Stopped -or $Suspended) { $state = "" if ($Running) {$State += " or enabledState = " + [int][VMState]::Running } if ($Stopped) {$State += " or enabledState = " + [int][VMState]::Stopped } if ($Suspended) {$State += " or enabledState = " + [int][VMState]::Suspended } $state = $state.substring(4) $WQL += " AND ($state)" } Get-WmiObject -computername $Server -NameSpace $HyperVNamespace -

Query $WQL | Add-Member -MemberType ALIASPROPERTY -Name "VMElementName" -

Value "ElementName" -PassThru

} elseif ($name.__class) { Switch ($name.__class) { "Msvm_ComputerSystem" {$Name} "Msvm_VirtualSystemSettingData" {get-wmiobject - computername $Name.__SERVER -namespace $HyperVNamespace -Query "associators of {$($name.__path)} where resultclass=Msvm_ComputerSystem"} Default get-wmiobject -

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computername $Name.__SERVER -namespace $HyperVNamespace -Query "associators of {$($Name.__path)} where resultclass=Msvm_VirtualSystemSettingData" | ForEach-Object {$_.getRelated("Msvm_ComputerSystem")} | Select-object -unique } } } } }

As you can see, the code basically wraps the WMI class with some helper logic and reports

the results.

Get-VMSwitch -- Returns all the virtual switches on the Hyper-V server (see Figure 2).

Figure 2: Get-VMSwitch command

The following code demonstrates the Get-VMSwitch command:

Function Get-VMSwitch {# .ExternalHelp MAML-VMNetwork.XML param( [parameter(ValueFromPipeline = $true)][Alias("Name")] [String]$VirtualSwitchName="%",

[parameter()][ValidateNotNullOrEmpty()] $Server = "." #Can query multiple servers for switches ) process { $VirtualSwitchName=$VirtualSwitchName.replace("*","%") Get-WmiObject -computerName $server -NameSpace $HyperVNamespace -query "Select * From MsVM_VirtualSwitch Where elementname like

'$VirtualSwitchname' " } }

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Get-VMSnapShot -- Provides all the snapshots on the Hyper-V server (see Figure 3).

Figure 3: Get-VMSnapShot command

The following command demonstrates the Get-VMSnapShot command:

Function Get-VMSnapshot {# .ExternalHelp MAML-VMSnapshot.XML Param( [parameter(Position=0 , ValueFromPipeline = $true)] $VM = "%",

[String]$Name="%",

[parameter()][ValidateNotNullOrEmpty()] $Server="." , [Switch]$Current, [Switch]$Newest, [Switch]$Root ) process{ if ($VM -is [String]) {$VM=(Get-VM -Name $VM -Server $server) } if ($VM.count -gt 1 ) {[Void]$PSBoundParameters.Remove("VM") ; $VM

|

ForEach-object { Get-VMSnapshot -VM $_ @PSBoundParameters}} if ($vm.__CLASS -eq 'Msvm_ComputerSystem') { if ($current) {Get-wmiobject -computerNam $vm.__server - Namespace $HyperVNamespace -q "associators of {$($vm.path)} where

assocClass=MSvm_PreviousSettingData"} else {$Snaps=Get-WmiObject -computerName $vm.__server -NameSpace

$HyperVNameSpace -Query "Select * From MsVM_VirtualSystemSettingData Where

systemName='$($VM.name)' and instanceID <> 'Microsoft:$($VM.name)' and elementName like '$name' " if ($newest) {$Snaps | sort-object -property creationTime | select-object -last 1 } elseif ($root) {$snaps | where-object {$_.parent -eq $null} } else {$snaps} }

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} } }

PSHyperV includes several additional functions to help admins perform related tasks,

including finding, manipulating and configuring different components of the hypervisor and

can be found on the CodePlex website.

Writing WMI wrappers and using PSHyperV are just a few of the ways admins can manage

Hyper-V using PowerShell. Note that the latest release of PSHyperV isn’t a complete

version, and thus, isn’t as stable as other options may be.

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Resources from Dell Compellent

Dell Compellent and Microsoft Integration: Automating and Creating Efficiency for

the Data Center

Self-Service Provisioning and the Private Cloud

The Right Team to Power Efficiency

About Dell Compellent

Compellent Technologies (NYSE: CML) has created a revolutionary enterprise storage

solution that automates the movement and management of data at a more granular level.

We call it Fluid Data, and it’s the future of data storage. This patented, built-in storage

intelligence delivers significant efficiency, scalability and flexibility. Only a Fluid Data

architecture can actively, intelligently manage your data to cut cost, time, and risk for your

business. With an all-channel sales network in 35 countries, Compellent is one of the fastest

growing enterprise storage companies in the world.