Microsoft provide a scaling solution for Windows Virtual Desktop at docs.microsoft.com. It is not as fully featured as other scaling solutions but it does a decent job of powering off and powering on the virtual machines during peak and off peak hours.

One thing it doesn’t do is adjust the time offset automatically, and this causes a problem when the clocks change.

In the UK we have just moved from British Summer Time (UTC+1) to Greenwich Mean Time (UTC+0). This means that the peak hours defined in the WVD Scaling tool are off by one hour.

Checking the offset

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  • Under Process Automation click on Jobs

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  • Click on the latest job

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  • In the job details page click All Logs

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  • In my log file the time offset is incorrect - the execution time is 09:27:23 but the script has added my UTC+1 offset and thinks the time is actually 10:27:23

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Fixing the offset

I fixed this by editing the Logic app directly.

If you make a mistake in this section you could prevent your logic app from running, or worse.

Test before making changes to a production environment

  • In the Azure portal, navigate to Logic Apps. Select your scheduler app (the name should be hostpool_AutoScale_Scheduler)
  • Under Development Tools click Logic App Designer

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  • Click on HTTP

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  • The UTC offset is listed as “TimeDifference”. In my environment it was set to UTC +1:00, British Summer Time (BST) alt text

  • For the UK we need to change this to +0:00 UTC (GMT) alt text

  • Click Save

Checking that it has worked

You could wait for your next run of the app, but I just clicked the Run button at the top of the Logic app designer. Once the app has run, we can check the logs again. In my environment the time is now set with the correct offset again alt text

Summary

The scaling tool is great for reducing the cost of running WVD, but it is a bit rough around the edges.

Hopefully an automatic time zone correction will be implemented in a future version before the next summer time change.