How to deploy a Resource via ARM Templates even if it’s not documented ?

Hi,

Recently, i tried to enable the Update Management Service in Azure Automation via ARM template. Not very complicated, many blog posts and examples can be found over the www.

But what i have not found anywhere is how to to create an Update Deployment Configuration via ARM template (what you see in the picture)

After about 10 minutes of searching the net, i decided to to it myself. But the question is : if it’s undocumented, how can i guess the ARM template json definition?

Two questions arose:

1- Is this supported via ARM templates?

2- How to do it in case it’s supported?

Since no documentation can be found, question 1 answer can be hard to find, but if i answer question 2 and test it, i can answer my question 1.

1- What are ARM templates after all?

Long story short, all ARM deployments are basically Rest API calls, so any ‘operation’ is supported through Rest API. ARM templates are just the Rest API content (the Body of the Rest call, for POST Requests).

So when you write an ARM template, you create the BODY of the Rest call and you send it to Azure. Azure will use it under the hood to create the Rest calls and bingo.

NB: i’m not sure whether the Template to Rest is made at client side (powershell, cli) or at server side, but this is not important in our case.

So the KEY here is that: If you can get the Rest Call Body, you can ‘probably’ get the ARM template JSON definition.

NB: Before continuing, try first to export the ARM template of your resource or resource group and look if you find the JSON definition of your resource. If you don't find it, go to section 2

2- How to get the Rest API Body content?

There are many ways to get this:

  • You can use ARMclient
  • You can use dev tools in the Azure Portal
  • You can use any tool that can unwrap a http request and let you see inside (your favorite tool)

3- Getting the Body Content using the Azure Portal

In my example above, my goal is to create an Update Management Deployment via ARM template, so i started like the following:

1- Go to the Azure Portal and use the wizard to create the UMD, but before submitting the creation b(Create Button) , make step 2

2- Use the Dev Tools (F12 in chrome and Firefox) and start recording a session

3- Submit the creation (Click Create in my case)

4- Stop the recording

5- Find the request that contains the Rest call for your operation

6- Take the following information:

  • Resource Type: It’s contained in the Request URL. In my example it’s Microsoft.Automation/automationAccounts/softwareUpdateConfigurations
  • api-version
  • Body: It’s contained in the Request Paylaod. You can use the ‘view source’ to get the Json definition directly. It contains the name of the resource and the Properties

4- Authoring your ARM template

I will not go through the ARM template Authoring, but you know, prepare a basic ARM Template with parameters and Resources at least (resources is the only needed part actually)

A resource json definition in an ARM template has usually the following format

{
	"$schema" : "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
	"contentVersion" : "1.0.0.0",
	"parameters" : {},
	"variables" : {},
	"resources" : [
		{
			"type" : "",
			"dependsOn" : [],
			"apiVersion" : "",
			"name" : "",
			"location" : "",
			"properties" : {}
		}
	]
}

Here the view with Json Edit (http://tomeko.net/software/JSONedit/)

Now, you guess it, fill the blanks:

That’s it, you achieved 95% of the ARM template, now you need to adapt it to your context (add parameters, variables, concat, functions if needed…)

5- Deploying the ARM template

Now, you can deploy your ARM template and have the answer to question 1 (in fact, we are not yet sure that this is supported through ARM templates, even if it’s supported via Rest API)

I don’t have the screenshot, but the deployment was successful, and i was able to author an ARM template even if no documentation is provided. This is great!

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