I have recently been looking at using Azure Resource Manager templates (ARM) to deploy and redeploy resources in Azure. I haven’t really done a lot with ARM templates so I though it might be helpful to do a few test runs and try figure out how to deploy resource in Azure using ARM templates.

In this post we will be going to through creating a ARM template from an existing resource group and what we need to do to redeploy to a new resources group.

ARM Templates are JSON files that define the infrastructure and configuration that will be deploy.

https://azure.microsoft.com/en-gb/services/arm-templates/

First we are going to export the template from Azure resource group that we want to redeploy to another resource group.

Logon to the Azure portal and go to resource groups.

Select the resource group that we want to export the template from.

Go to Automation and select export template.

This will bring up the ARM template for the resource group. We can then download the template to modify, I will be using visual studio code with the Azure Resource Manager (ARM) Tools extension added to edit the template.

Once the zip file is download and extracted there will be two JSON files, parameters’ and template.

When we look at the template file itself there will be a set of parameters. There are default values for each parameters which are the names of each resource in the resource group. I remove the default values.

The parameters are what is used to define the name of the resources that are created.

When I first started to look at the ARM templates they did seem very confusing but if you break them up in to each part instead of looking at it as a whole it made a lot easier for me to understand how the template worked.

If we take the below as a example this part of the JSON defines the virtual network and subnet to be created. It sets the location, subnet prefixes and one subnet for 10.0.0.0/24.

If there are IP address assigned or the subnet need to be changed this can be updated in the JSON file.

Once the JSON file has been modified we can then use this to deploy to Azure. The two way we will be going through in this post is using Azure portal Deploy from a custom template and second we will be going through adding the parameters to the parameters JSON and deploy using PowerShell.

First we will go through the portal deployment.

Logon to the Azure portal and go to deploy from a custom template.

We could search for template using the quick start template if we don’t have a existing template

but we will be using build your own template so we will be selecting build your own template.

Once the blade opens click load file and select the JSON template file this will then load the template.

Click save this should then a view like the below that we can manually in put the details we want to use for the deployment.

Click next and the arm template will be validated.

Click create to start the deployment.

When I deployed the template I had some issues with the VM creation.

This was caused by a few different issue. The first was the managed disk which returned the below error.

“Parameter ‘osDisk.managedDisk.id’ is not allowed.”

I found this article on Github https://github.com/Azure/azure-quickstart-templates/issues/3290 that explained the fix was to change the manageddisk from

to the below storage account type

The second issue was to do with requireGuestProvisionSignal property. I found the below forum post that said to remove the line.

https://docs.microsoft.com/en-us/answers/questions/332816/the-property-39requireguestprovisionsignal39-is-no.html

I removed this from the JSON.

The last issue was due to the admin password not being set. To fix this I added a new parameter at the start of the template

and set it under below under os profile

Once this was done I went back to deploy a custom template and readd the details which should now have the addtional admin password field.

The deployment now completed without issue.

The resources now be deployed to the resource group.

The second method we will be going through to deploy the ARM template is to use PowerShell.

We will be using the New-AzResourceGroupDeployment command to deploy the template.

We first will be modifying the parameters file to set the names that will be used.

For the adminpassword I will be adding the password to the parameter’s file but in production this should not be done and instead use something like Azure key vault to store the password.

First we need to install the Azure module

Install-Module -Name Az -Scope CurrentUser -Repository PSGallery -Force

Next we run

Connect-AzAccount

Next we run the New-AzResourceGroupDeployment I used the verbose parameter to get more details on the deployment. We will be calling the template and parameter JSON files.

New-AzResourceGroupDeployment -ResourceGroupName "resource group"  -TemplateFile "path to template json" -TemplateParameterFile "path to parameters json" 

Below is the command running and provisioning the resources in the template.

Once the deployment completes all the resources will show under the resource group.

We can also use the ARM template to redeploy a resource that has been removed.

If we run the New-AzResourceGroupDeployment again after a resource has been deleted the deployment picks up that the missing resources and redeploys.

This was my first attempt at doing ARM and it not as complicated as I first thought I will probable do a few more post in the future after I have some more time working with ARM templates.