DSCR and Pester testing

In my previous post DSCR for VMware and you! I described the open source project that was started to develop DSC resources for vSphere (DSCR). One of the requirements for contributing, is that you provide Unit and Integration Pester tests for any new DSC resource you contribute to DSCR.

The vSphere environment and VMware PowerCLI have some peculiarities that will require you to use some specific Pester techniques to write these Pester tests. This post should help you understand how this done. This is not intended as a Pester course, there are other, and better, resources for that.

Continue reading DSCR and Pester testing

DSCR for VMware and you!

On December 13th 2018 the PowerCLI Team provided us with an early end-of-year present. The Desired State Configuration Resources (DSCR) for VMware are published, and they are open sourced!
If you missed the announcement, hold what you are doing, and go read the VMware PowerCLI blog post Getting Started with Desired State Configuration Resources for VMware right now!

The next question on your mind is probably “How can I contribute?“. Well, with the correct tools and some VMware PowerCLI knowledge, it turns out that this is not too difficult. What follows is my first attempt at contributing to the Desired State Configuration Resources for VMware.

Continue reading DSCR for VMware and you!

Message to all users, and their reply

Before you need to reboot a VM, or do some destructive maintenance on there, it is a good practice to at least tell the user(s) of that VM what is going to happen. But how do you address the users of a VM? They can be connected to a console (local) or via a RDP session (remote). And how do you get their reply back?


Exactly such a question appeared in the VMTN PowerCLI Community recently. And after some digging, it seems that is possible through a PowerShell script that uses the Remote Desktop Services API, provided through the wtsapi32.dll. Note that the VMs we are looking at, all are running a Windows guest OS.

Continue reading Message to all users, and their reply

vSphere Permission cleanup

Your vSphere environment is a living environment. Inventory objects are created and removed all the time. Together with these inventory objects there are often security permissions that come along. Team X needs Power User access for all VMs in folder Project-X. But the life-cycle management of these permissions is often not as fluent as your VM life cycle management. There is no built in permission cleanup method.

As a result, old permissions might be left behind, and what is worse, redundant permissions might be present. This doesn’t make the task of investigating “Who can do what?” in your vSphere environment any easier.

With the help of the function in this post you can now get rid of all these redundant permissions!

Continue reading vSphere Permission cleanup


The Invoke-VMScript cmdlet is definitely one of the PowerCLI cmdlets that is indispensable when you need to do things inside the Guest OS of your VMs.

When you are interacting with a Windows based Guest OS you can run old-fashioned BAT files or use PowerShell scripts. When the Guest OS is Linux based, you currently only can run Bash scripts.

Most Linux flavours have a feature that is called SheBang, and which allows you to specify in the first line of your bash script, which interpreter shall be used to run the following lines of the script. Unfortunately, the current Invoke-VMScript cmdlet doesn’t allow one to use that feature.

Time to tackle that issue, and expand the possibilities for all VMs that have a Linux-based Guest OS. So I decided to write my Invoke-VMScriptPlus function.

Update October 14th 2017

  • Added here-document bash sample

Continue reading Invoke-VMScriptPlus

Get-EsxTop – Another Look

One of the lesser used PowerCLI cmdlets must be the Get-EsxTop cmdlet.

It’s not that the Get-EsxTop cmdlet is not very useful, on the contrary. In my opinion, the main reason for it’s infrequent use might be the complexity involved to actually use the data it returns. Add to that a somewhat lacking documentation, and the Ugly Duckling of the PowerCLI cmdlets is born.

But just like in the story, this cmdlet has the potential to grow up, and transform into a beautiful swan.

Get-EsxTop post

I already did some Get-EsxTop posts in the past, see Hitchhiker’s Guide to Get-EsxTop – Part 1 and Hitchhiker’s Guide to Get-EsxTop – Part 2 – The wrapper. But a recent thread in the VMTN PowerCLI Community made me rethink how the Get-EsxTop cmdlet could be put to better use. The author of the thread wanted to compare the results returned by Get-EsxTop with the data displayed in esxtop. He also compared the calculated Get-EsxTop metrics with those returned by the Get-Stat cmdlet, and there were some serious discrepancies!

Continue reading Get-EsxTop – Another Look

Orphaned Files Revisited

In my Orphaned files and folders – Spring cleaning post from way back, I provided a script to find orphaned VMDKs. This week there was a post in the VMTN PowerCLI Community that had a request to find all orphaned files. Time for a revisit of my old post!



I took my old script, massaged it a bit and gave it a more contemporary look and feel.
Just for info, the SearchDatastoreSubFolders method is relatively slow. So scanning a couple of datastores for orphaned files might take a bit of time. Be patient 🙂

Continue reading Orphaned Files Revisited

vSphereDSC – Principles of Operation

The “Principles of Operation” in the title is in fact just an expensive expression for “How do I use this stuff ?”. In this post I will try to show you how you can use the vSphereDSC module, as a user, and as a contributing developer. On the side, it also shows you how you can use these vSphereDSC resources.

The vSphereDSC module contains a set of DSC resources to can be used to configure a vSphere environment. These DSC resources can be used against any vSphere Server, beit a vCenter or an ESXi node. On the condition of course that the selected resource is supported on the vSphere Server.


For “users” of the vSphereDSC resources, the post will show how to automate keeping the module up to date and how to manage the life cycle of the Configuration files that are build on the vSphereDSC resources.

For those of you that want to contribute to the development of the vSphereDSC module and it’s resources, this post will also show how you can automate the testing phase. In a first instance through a number of PowerShell scripts, in a later phase through the use of a build server.

Continue reading vSphereDSC – Principles of Operation

vSphereDSC – VmwFolder

In this post I’ll introduce the first DSC resource from the vSphereDSC module, the VmwFolder resource. Since this is the first post in the series, I will also expand a bit on how the vSphereDSC module is set up and which conventions I’m using.


A vSphere Folder is a resource which can exist rather independently in an existing vSphere environment. You can easily create some test Folders to get the hang and feel of the vSphereDSC module and play with DSC Configurations based on this vSphereDSC resource.

Continue reading vSphereDSC – VmwFolder

vSphereDSC – Intro

My attempts to marry DSC and vSphere have been going on for nearly a year* now. I showed some of my attempts and intermediate results at VMworld 2015, in two sessions at the PowerShell + DevOps Global Summit and recently during a session at the 24th VMUGBE+. But now I’m finally going public with the vSphereDSC module.

Since WMF 5 has been made available in preview, and still is in RTM at the moment I’m writing this, there have been constant changes to the way I was writing the DSC resources for vSphere. Since the February 2016 WMF 5 release, I now have a (somewhat) stable, working class-based solution. At least, that is what my initial tests seem to indicate.


This intro for my vSphereDSC series, will lay out the playing field. I’ll explain the concept I’m using, show some of the issues I encountered and explain the layout of the vSphereDSC Resource module.


* “Wisely and slow; they stumble that run fast”, Romeo and Juliet, Act II, Scene III

Continue reading vSphereDSC – Intro