Exploring the PowerShell DSC xPendingReboot Resource

While building a DSC Demo for the new job this week I got the chance to explore using many of the “new” Resources that have been released.  One of those Resources is the xPendingReboot which I am going to talk about here, because the documentation wasn’t very clear (to me anyways after having been away from DSC for a long time) on how to use it properly.

The TechNet article on the Resource and an article by the Scripting Guy can be found at the links below.

https://gallery.technet.microsoft.com/scriptcenter/xPendingReboot-PowerShell-b269f154

http://blogs.technet.com/b/heyscriptingguy/archive/2014/10/15/use-powershell-dsc-to-check-pending-reboot.aspx

If you just look at it, you would assume you could do something like this to check for a reboot:

However, you would be wrong! If we create the .MOF file for this Configuration and run this against the local system (which has a reboot pending after a computer rename), the system doesn’t actually reboot itself, it just notifies you that a reboot is pending.

Well, that’s great and all but it didn’t reboot the machine like I needed it to. Looking at those examples, maybe I need to add the LocalConfigurationManager piece to make this work?

When you build this Configuration you will immediately notice you get a localhost.mof as well as a localhost.meta.mof . The Meta.mof is a result of making a change to the Local Configuration Manager (LCM) and should be a hint that something needs to be done with it :). The TechNet article uses a RebootNodeifNeeded = ‘True’ instead of the Boolean $True, which is not correct. If you try to build the Configuration using ‘True’ you get this error:

I am going to ignore the localhost.meta.mof file for now and just try this again to see what happens. And the exact same thing happens. If you are wondering if moving the LocalConfigurationManager section ahead of the xPendingReboot section matters or will help, it won’t. You actually need to change the LCM setting on the computer before starting the Configuration, because right now it is set to this. Notice the RebootNodeIfNeeded section at the bottom:

You do that by using this command:

Now when we start the Configuration, we get the exact same result as above, plus an automatic reboot!
PendingReboot






If you want everything in one file, you can find it here.

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