ARM Templates – Create multiple Instances by using ‘copy’

When using ARM templates you often end up with many lines of code. There are some gems available that help you reducing your code to a minimum (which normally is still a lot). If you need to create multiple instances of resources, there is a function available that helps you to achieve this goal with very few code. By using a simple ‘copy’ one can create multiple instances of a specific resource.In this example I want create five resource group by using the copy/count property. Of course, all instances need unique names, this is why I use the copyIndex() to generate the resource name. copyIndex represents the iteration number of the resource creation loop.

{
  "$schema":"https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion":"1.0.0.0",
  "parameters":{
    "location":{
      "type":"string",
      "defaultValue":"West Europe"
    }
  },
  "variables":{
  },
  "resources":[
    {
      "type":"Microsoft.Resources/resourceGroups",
      "apiVersion":"2018-05-01",
      "location":"[parameters('location')]",
      "name":"[concat('w-rgr-user',copyIndex())]",
      "copy": {
        "name" "resourcegroupcopy"
        "count": 5
      }
    }
  ],
  "outputs":{
  }
}

The result looks like this:

Resource Groups

As the name is concatenated from the prefix ‘w-rgr-user’ and the copyIndex, you can see that the first iterations obviously has the iteration number 0. This can be changed by adding a copyIndex offset.

"name":"[concat('w-rgr-user',copyIndex(11))]",

This now starts the iteration counting with 11 and so the results now looks like this:

Resource Groups

If you want to add more meaningful names this can also be done. For that, the template needs to be modified slighthly. Let’s say we want to include a personal name in the resource group name.  For that I added a new parameter that holds all five names I need in an array of default values. To create the name I now need to iterate through the five names by using the copyIndex value (0-4) to access the values in the parameters array. 0 would be Marcel, 1 would be Alexa etc.

{
  "$schema":"https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion":"1.0.0.0",
  "parameters":{
    "location":{
      "type":"string",
      "defaultValue":"West Europe"
    },
    "resourceGroupNames": {
        "type": "array",
        "defaultValue": [
          "Marcel",
          "Alexa",
          "Siri",
          "Peter",
          "John"
      ]
    }
  },
  "variables":{
  },
  "resources":[
    {
      "type":"Microsoft.Resources/resourceGroups",
      "apiVersion":"2018-05-01",
      "location":"[parameters('location')]",
      "name":"[concat('w-rgr-', parameters('resourceGroupNames')[copyIndex()])]",
      "copy": {
        "name" "resourcegroupcopy"
        "count": 5
      }
    }
  ],
  "outputs":{
  }
}

Again, this is the results looks like.

Resource Groups

That’s it. Have fun!

Cheers,
Marcel

About Marcel Zehner

Microsoft Azure MVP
This entry was posted in Azure, DevOps and tagged , , , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s