Bug in xWebAdministration module in DSC resource kit on Windows 2008 / IIS7

At one of the clients that I’m working we’re doing a proof of concept on using Release Management vNext type release templates for deploying their application. We’re using Powershell Desired State Configuration (DSC) for the actual deployment script.

One of the requirements is that we should also be able to deploy to the existing environments, running Windows 2008R2 and IIS7. Since the application is a simple web application, I was using the xWebAdministration module from the DSC Resource kit. When deploying to a Windows 2012R2 machine with IIS8, everything worked like a charm. However, when deploying on a Windows 2008R2 machine with IIS7, I got all sorts of weird error messages. There were already a couple of websites running on that machine, and it seemed as if the DSC script was trying to update those. Of course, it shouldn’t touch already existing sites.

After a bit of searching, I ran into this bug on Connect. Apparently there is a problem with the “Get-Website” cmdlet on IIS7. It returns all websites, instead of only the one specified with the “-Name” parameter. Since the xWebAdministration module uses “Get-Website -Name xyz” to get a reference to the website it should modify, it’ll try to update all the websites in the IIS server. So that explains it. Now, how to solve this?

Actually, the solution is not very complicated. The easiest is to modify your copy of the xWebAdministration module. Open the “MSFT_xWebsite.psm1” file in your favourite editor. You’ll find it in the “DSCResources\MSFT_xWebsite” folder.

Then, do a “find and replace” and replace this:

$Website = Get-Website -Name $Name

With this:

$Website = Get-Website | Where { $_.Name -eq $Name }

You should find five occurrences of the above snippet. After doing the replace, save the file and run your deployment again. If all is well, it should work now 🙂

Happy deploying!

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