Wednesday, September 27, 2017

Checklist for troubleshooting compilation of DSC Configuration in Azure Automation

I was recently working on a solution where a DSC Configuration block was not compiling in Azure Automation. This solution included Node Data, DSC Resources, and custom Composite Resources. The configuration would compile perfectly fine locally but not when published to Azure Automation. The other challenging aspect was that other composite resources within the same module were compiling fine.

Unfortunately Azure Automation doesn’t provide very detailed information for troubleshooting DSC Compilation errors. It actually will only show you the first level failure, which when your using a DSC Composite Resource it means you will simply receive an error that the composite resource failed to import, but the actual cause could be related to a problem with an underlying resource used by that composite resource.

So based on my experience I have come up with the following troubleshooting checklist when working through DSC Compilation errors in Azure Automation.

Troubleshooting Checklist
  1. Check the exception details output by the DSC Configuration compilation job that is in the suspended state. Either within the Azure Portal like the following screen shot or via PowerShell by the Get-AzureRmAutomationDscCompilationJobOutput cmdlet.

    Depending on the exception reported the next steps may vary. In the above screenshot it is reporting that a Composite Resource has failed to import.
  2. Can you compile the configuration locally?
    1. If yes, can you upload the MOF to the DSC Node Configurations in the Azure Automation account?
  3. Are all required Modules referenced by your Configuration(s):
    1. Uploaded to your Azure Automation account
    2. Up-to-date (see next point though)
    3. Match the required version by your Configuration block or Composite Resource
  4. If it is a Composite resource that is failing, are all Composite resources within your module affected or is it just a subset?
  5. If it is a Composite Resource, extract the configuration from the failing Composite Resource and place it directly in a Configuration block. Compile that configuration block in Azure Automation and review the output as this will provide more granular details about the specific resources used by that configuration block.
  6. Try simplifying the DSC Configuration block to reduce the number of DSC Composite resources or other resources being compiled to help narrow down the culprit

You should also read the "Common errors when working with Desired State Configuration (DSC)" section in the official documentation

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