ARM Templates: What Error?!?


There is more than one way to deploy an ARM template once you’ve created or edited on to your liking. The first way is to copy the code into a blank template deployment in the Azure portal. This has a few benefits, primarily that it gives you the option to edit any parameters in the template to your liking before deployment and saves you from having to write a separate “azuredeploy.parameters.json” file.

However the deployment blade in the portal doesn’t really give you much in the way of error messages when the template fails. Often, you are give something along the lines of “error exists on line 1: position 10,374” or some such information. But your template is clearly more than one line in length and I have no intention of counting out thousands of characters to find the error location. The full text of the message may or may not be helpful depending on what point in the deployment the error occurred.

This is where deploying the template via PowerShell shines. As much as the red text is heartbreaking, it will give you the proper line number and position count to line up with your code. Also included is some often useable error text to point you on your way.

This single line of PowerShell will deploy a template that is hosted online (like in GitHub) and the -Verbose switch will report on the status of each of your resources as they start and complete deployment.

New-AzureRmResourceGroupDeployment -ResourceGroupName "<YourResourceGroupName>" -TemplateURI $templateFileURI -TemplateParameterURI $parameterFileURI -Verbose

If that doesn’t solve your problem or point you in the right direction, it’s time to dig deeper in the Azure Audit Logs from within the portal. They are chronological, so after a few clicks, you can drill down into the details of the most recent error. You can also access those logs via PowerShell:

Get-AzureRmLog -Status Failed -ResourceGroup "YourResourceGroupName" -DetailedOutput

You can also access these logs by digging down into the deployment in the portal. Just to “Audit Logs” and you’ll find all the activity in your subscriptions. Looked for the ones related to failed deployments or validations of deployments and as you drill into the details you’ll find what’s going wrong. Usually it’s an incorrect location of a parameters file, maybe a storage account name that’s already in use, or a missing resource group.

Happy Hunting!

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