Azure customscriptextension can't find script file

Question

I'm using Powershell and a JSON file to create new VM's. The last part of the JSON file instructs the newly-created VM to run a file. I can verify (via the Azure portal and via Powershell) that the file exists at the URL given in the JSON file.

Yet the VM finishes with result ProvisioningState:Failed because VM has reported a failure when processing extension 'CustomScriptExtension'. Error message: "Finished executing command" which is frustratingly ambivalent. (We've also had problems with the domainjoin CustomScriptExtension which also "failed" with a "success" message.)

The script, which is a simple CMD file, should create the file C:\Users\Public\Documents\runonce.log, but this does not happen so I guess the file does not run.

However, the VM is created, and I can then manually log in and run the file just fine. So it should not be a matter of user privileges or such.

Edit: This comment states that "CustomScriptExtension does not run with local admin priviledges", but I don't think that's the problem here.

What am I missing?

Here's the relevant part of the JSON:

...
"resources": [
    ...
    {
    "type": "Microsoft.Compute/virtualMachines/extensions",
    "name": "[concat(parameters('vmName'),'/CustomScriptExtension')]",
    "apiVersion": "2015-05-01-preview",
    "location": "[resourceGroup().location]",
    "dependsOn": ["[concat('Microsoft.Compute/virtualMachines/', parameters('vmName'))]"],
    "properties": {
        "publisher": "Microsoft.Compute",
        "type": "CustomScriptExtension",
        "typeHandlerVersion": "1.2",
        "settings": {
            "fileUris": ["[concat(parameters('scriptFilePath'),parameters('scriptFileName'))]"],
            "commandToExecute": "[concat('powershell -ExecutionPolicy Unrestricted -file ',parameters('scriptFileName'))]"
        }
    }
}]

and I have verified that scriptFilePath and scriptFileName are https://euwest2766.blob.core.windows.net/script/ and run-once.cmd which corresponds to the blob URL shown in Azure. I have even tried putting that Azure Blob URL into the JSON, with the same result.

Answer 1

This won't work because you are trying to run a batch file through Powershell.

you would need to change this -

"commandToExecute": "[concat('powershell -ExecutionPolicy Unrestricted -file ',parameters('scriptFileName'))]"

to this

    "commandToExecute": "[concat('cmd /s',parameters('scriptFileName'))]"

That should execute as expected.