Virtual Machine Manager’s PowerShell Support

re: Virtual Machine Manager’s PowerShell Support

Weidong Cui — Sat, 05 Dec 2009 01:27:25 GMT

Hi Jeffrey,

I installed SCVMM 2008 R2, but I couldn't find the cmdlet Get-DVDDrive as you used in your article. Can you please give me some pointers on how to use the powershell scripts shipped with SCVMM?

Thanks,

Weidong

re: Virtual Machine Manager’s PowerShell Support

PowerShell Team — Sun, 02 Aug 2009 04:02:06 GMT

1) Aliases can map to anything not just cmdlets that is why the parameter name is -VALUE

2) We should have REMOVE-ALIAS. Full stop. We prioritized other features. The way you do it is:

Remove-Item Alias:name

I'd appreciate the details for #4. V2 should run V1 scripts with perfect fidelity modulo bug fixes.

jps

PowerShell Method Signatures

neilhmurhphy — Sat, 01 Aug 2009 22:14:15 GMT

I have given up on powershell as a scripting language because:

1) I tried to establish an alias without the book in front of me. You try it "Get-Help Set-Alias" now which is the alias and which is the commandlet. Please note that I did look in the book and the syntax given there is not what "Get-Help Set-Alias" returned.

2) There is no "Delete-Alias" so my only option was to uninstall the product and the reinstall. Is this how to run a railroad (or language)?

3) Because in the two MS books (Step by Step & Guide) that I have the string methods are essentially undocumented I wrote a script using what I could find (including stuff on .VBS). Then I started writing the script that I wanted.

4) The two scripts behave quite differently (under both v1 and v2 of PS) even though they are syntactically identical. The error messages only further demonstrate PowerShell's inadequacy.

5) A null string obviously does not "Contain" anything so the result should be "False" not an error message.

If you send me an e-mail at yahoo I would be happy to reply with additional documentation.

re: Virtual Machine Manager’s PowerShell Support

Ben Christian — Mon, 19 Mar 2007 11:00:58 GMT

I'd have to say that I'm pretty impressed with how easy it is to write scripts for SCVMM using PowerShell. The hardest part is that there isn't any documentation yet and there aren't many people blogging about it. Your code sample was about the only peice of sample code that I could find, yet from that I was able to work out how to start and stop VMs and create checkpoints without too much trouble. I've posted my progress at http://www.benchristian.com and have included some sample scripts that I have created.

I've done quite a bit of scripting with vbscript and can say that PowerShell is a lot easier work with. I have to point out though that I when it comes to virtualisation, Microsoft have a lot of catching up to do before they can compete with VMWare. Having said that, the company that I work for almost exclusively uses Microsoft products so SCVMM is very warmly welcomed!

re: Virtual Machine Manager’s PowerShell Support

Rakesh Malhotra — Tue, 13 Feb 2007 08:05:52 GMT

Thomas - you're making the right point. We were able to use Powershell and its constructs to create an excellent "user interface" for scripting. Sure, we had to write the cmdlets but now you don't have to.

In fact, our entire user interface for SCVMM is built on top of powershell which means our UI developers use it as their API. That type of approach forces a certain amount of rigor and thought in your scripting interface design. Our API is your API. If it's hard to script for you, it's hard to write and maintain code for us as well. With the object-based constructs that powershell provides, this type of design decision was a no-brainer for us and it keeps us honest with customers.

re: Virtual Machine Manager’s PowerShell Support

Thomas — Wed, 07 Feb 2007 20:16:50 GMT

Those who have pointed out that Virtual Server cmdlets had to be written are, I think, missing the point: VMware commands also had to be written. Indeed, the designs of the respective cmdlets/commands are an important part of the comparison, in my view.

The point, as I see it, is to show the difference in philosophies, with the VMware commands being based on the traditional Unix model of generating and processing text streams, whereas the Virtual Server cmdlets are based on the PowerShell model of interacting with self-describing objects.

You could use PowerShell to process text streams generated by something like vmware-cmd, but that wouldn't be making use of the object-based nature of the shell, which is one of its key advantages over traditional shells like bash, and hence would be rather pointless. On the other hand, a traditional shell like bash doesn't include any notion of objects, so simply isn't capable of working in the way that PowerShell does.

re: Virtual Machine Manager’s PowerShell Support

16aR — Thu, 01 Feb 2007 15:29:11 GMT

Hello,

Those 2 scripts cannot be compared, they aren't based on the same VMWare utilities (vmware-cmd)

Just rewrite the powershell script using the vmware-cmd, and then you can compare it. I can write the same type of your powershell script using bash, using my own own cmdlet developed for that

re: Virtual Machine Manager’s PowerShell Support

Don — Wed, 31 Jan 2007 18:50:48 GMT

Jerry, the difference is that in the Windows world we DON'T already have thousands of cmdlets. I think you may have looked at the comparison differently; this isn't Linux vs. Windows. This is Windows vs. Windows - that is, an older way of scripting vs. a newer way - something that we haven't had. Yes, a Linux script was used, but it's substantially similar to what we'd have had to do on Windows, too. Your point about how Linux focuses on the command line before the UI is exactly the point of PowerShell. No, it's not earth-shattering for the IT industry as a whole - but for Windows, it is - we've never been ABLE to think like this. PowerShell DOES make the situation different - for Windows. Since PowerShell isn't made for Linux, Linux really "don't enter into it," apart from the fact that PowerShell borrows a lot of great ideas from *nix and brings them to Windows.

PowerShell Support for Virtual Machine Manager

Dugie's Pensieve — Wed, 31 Jan 2007 01:44:19 GMT

Clive beat me to it again! PowerShell uberguru Jeffrey Snover has blogged " Virtual Machine Manager’s

re: Virtual Machine Manager’s PowerShell Support

Jerry Haltom — Wed, 31 Jan 2007 00:32:43 GMT

I don't get it. This is nothing special. Some dude had to go and write 3 cmdlets to make this happen. The same dude could have written 3 bash scripts to source. Same stuff.

There is no magic here.

The difference is in the Linux world, we already have thousands of 'cmdlets', because people focus on writing the command line interface before the UI, instead of the other way around.

It's a bit disingenuous to suggest that PowerShell somehow makes this situation any different.