How to I prevent Microsoft.Automation/automationAccounts/Compilationjobs to always run in ARM deployment? - azure-resource-manager

Question

My ARM template is below which is nested template in bigger ARM template. For some reason DSC Compilation job always run on each deployment. I expected it not be run if it was already run before. How do I control this behavior? I tried using "incrementNodeConfigurationBuild": "false" but it did not do the trick.
{
"name": "WorkerNodeDscConfiguration",
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"resourceGroup": "[parameters('automationAccountRGName')]",
"dependsOn": [],
"properties": {
"mode": "Incremental",
"template": {
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.1",
"resources": [
{
"apiversion": "2015-10-31",
"location": "[reference(variables('automationAccountResourceId'), '2018-01-15','Full').location]",
"name": "[parameters('automationAccountName')]",
"type": "Microsoft.Automation/automationAccounts",
"properties": {
"sku": {
"name": "Basic"
}
},
"tags": {},
"resources": [
{
"name": "workernode",
"type": "configurations",
"apiVersion": "2018-01-15",
"location": "[reference(variables('automationAccountResourceId'), '2018-01-15','Full').location]",
"dependsOn": [
"[concat('Microsoft.Automation/automationAccounts/', parameters('AutomationAccountName'))]"
],
"properties": {
"state": "Published",
"overwrite": "false",
"incrementNodeConfigurationBuild": "false",
"Source": {
"Version": "1.2",
"type": "uri",
"value": "[parameters('WorkerNodeDSCConfigURL')]"
}
}
},
{
"name": "[guid(resourceGroup().id, deployment().name)]",
"type": "Compilationjobs",
"apiVersion": "2018-01-15",
"tags": {},
"dependsOn": [
"[concat('Microsoft.Automation/automationAccounts/', parameters('AutomationAccountName'))]",
"[concat('Microsoft.Automation/automationAccounts/', parameters('AutomationAccountName'),'/Configurations/workernode')]"
],
"properties": {
"configuration": {
"name": "workernode"
},
"incrementNodeConfigurationBuild": "false",
"parameters": {
"WebServerContentURL": "[parameters('WebServerContentURL')]"
}
}
}
]
}
]
}
}
}

Answer 1

In short, AFAIK you should be able to control this behaviour with 'condition'.
To explain it in detail, the DSC compilation jobs resource always run on each deployment because when we use the DSC compilation jobs resource (i.e., Microsoft.Automation/automationAccounts/compilationjobs) in the ARM template, IMHO what it does in the behind is, basically clicks on 'Compile' button of the DSC configuration.
If you click on that 'Compile' button, the compilation of job happens for sure even if it already compiled the job. You may check the same part manually as well.
So AFAIK that was the reason for compilation job always running on each deployment.
What you could do is, update your ARM template with 'condition' (For more information, refer https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-manager-templates-resources#condition and https://learn.microsoft.com/en-us/azure/architecture/building-blocks/extending-templates/conditional-deploy) and then wrap your template with below sample piece of PowerShell code that would determine if the Compilation of job for particular DSC configuration is done already and then deploy the template by passing inline parameter value or by updating condition parameter in parameters template file with new or existing value accordingly. (For more information, refer https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-group-template-deploy#pass-parameter-values)
$DscCompilationJob = Get-AzAutomationDscCompilationJob -AutomationAccountName AUTOMATIONACCOUNTNAME -ResourceGroupName RESOURCEGROUPNAME|Sort-Object -Descending -Property CreationTime|Select -First 1| Select Status
$DscCompilationJobStatus = $DscCompilationJob.Status
if ($DscCompilationJobStatus -ne "Completed"){
$DscCompilationJobStatusInlineParameter = "new"
New-AzResourceGroupDeployment -Name ExampleDeployment -ResourceGroupName testgroup -TemplateFile TEMPLATEFILEPATH\demotemplate.json -exampleString $DscCompilationJobStatusInlineParameter
#or update condition parameter in parameters template file with new value accordingly and use below command to deploy the template
New-AzResourceGroupDeployment -Name ExampleDeployment -ResourceGroupName ExampleResourceGroup -TemplateFile TEMPLATEFILEPATH\demotemplate.json -TemplateParameterFile TEMPLATEFILEPATH\demotemplate.parameters.json
}else{
$DscCompilationJobStatusInlineParameter = "existing"
New-AzResourceGroupDeployment -Name ExampleDeployment -ResourceGroupName testgroup -TemplateFile TEMPLATEFILEPATH\demotemplate.json -exampleString $DscCompilationJobStatusInlineParameter
#or update condition parameter in parameters template file with existing value accordingly and use below command to deploy the template
New-AzResourceGroupDeployment -Name ExampleDeployment -ResourceGroupName ExampleResourceGroup -TemplateFile TEMPLATEFILEPATH\demotemplate.json -TemplateParameterFile TEMPLATEFILEPATH\demotemplate.parameters.json
}
And regarding incrementNodeConfigurationBuild property, IMHO this property is just with regards to creation of a new build version of Node Configuration is required or not i.e., when incremental node configuration build is set to false, it does not override the earlier existing Node Configuration by creating a new Node Configuration with the name CONFIGNAME[<2>] (the version number is incremented based on the existing version number already present).
Hope this helps!! Cheers!! :)