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.

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Invoke-VMScriptPlus v2

The ability to execute scripts inside the guest OS of your VMs, is definitely one of the more useful cmdlets available in VMware PowerCLI. A year ago I published the first version of my Invoke-VMScriptPlus function to solve some of the issues the Invoke-VMScript cmdlet has in my opinion.
That function allowed you to run multi-line scripts in a Linux guest OS on your VMs. It also allowed you to use she-bang lines, to indicate which interpreter your script had to run in (bash, perl, python, nodejs, php…). Another handy feature was that you could use Linux here-documents in your scripts.

With the introduction of PowerShell Core (aka PowerShell v6), the lack of support for any Guest OS of the Windows family became obvious. Prompted by a recent thread in the VMTN PowerCLI Community, I decided it was time to publish a new version of my Invoke-VMScriptPlus function.

 

Update August 21st 2018

  • Added ScriptEnvironment

Continue reading Invoke-VMScriptPlus v2

Invoke-VMScriptPlus

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

Will Invoke-VMScript work ?

The Invoke-VMScript cmdlet can be a very useful cmdlet, but sometimes it will fail against one or more of your VMs. And it is not always immediately clear why the Invoke-VMScript cmdlet will not work against that specific VM.
The cmdlet help contains a number of prerequisites, but how do you verify if all the prerequisites are fulfilled?
I decided to create a function that would verify the prerequisites, and that would, if requested, which of the prerequisites was missing.

Continue reading Will Invoke-VMScript work ?