Importing Existing Azure Resource Groups into Terraform

Summary

Below is a quick guide on how to grab an existing resource group and add them to an existing state file. I found other guides felt a bit too complicated.

Prerequisites

• aztfexport installed
• Az CLI installed, signed in and configured to the target subscription

We’re not going to cover these steps in this document as it varies between different OS.

Steps

Note: For this example we’re using “TEMPRG” as the name of the Resource Group being copied so change it everywhere you see it to the Resource Group you’re importing!

1) In the terminal navigate into the root or your repository,

2) Run: aztfexport rg -o "TEMPRG" -hcl-only "TEMPRG" - The -o "TEMPRG" is the output folder, -hcl-only prevents it from creating statefiles and other bits we don’t need and then the final "TEMPRG" is the resource group in Azure itself.

3) An interactive screen will then appear where you can browse the resources and check for errors. Do take a few minutes to review this because somethings won’t import and in one situation I had to manually re-enable SAS Keys on a Storage Account through the portal because I could import it successfully. Once you have reviewed this, you can push w to export. This will then create the subfolder with a collection of your files.

4) Navigate into the terraform.tf file which was created in the subfolder and compare the hashicorp/azurerm version against the terraform.tf file in your main folder - If the subfolder differs you may need to update the main one and run terraform init -upgrade to change the version to ensure your Terraform project supports all the parameters being used.

5) Delete the /TEMPRG/provider.tf and /TEMPRG/terraform.tf files as these are not required when importing to an existing repository (we already have the provider)

6) In your main.tf file, add a module reference to the folder which contains the code that was generated.

module "TEMPRG" {
  source = "./TEMPRG"
}

7) To register the module, run terraform init

8) The last step is to run a command which loops through the JSON file of resources that was generated (/TEMPRG/atfexportResourceMapping.json) and adds them to the State file. This is the command using the “Fish” shell in Linux, at the bottom of this post are a few other variations:

set mapfile "/PATH_TO_YOUR_REPO/TEMPRG/aztfexportResourceMapping.json"
set module_name "TEMPRG"

for line in (jq -r --arg mod "$module_name" 'to_entries[] | "module.\($mod).\(.value.resource_type).\(.value.resource_name) \(.value.resource_id)"' $mapfile)
    set parts (string split -m1 ' ' $line)
    set addr $parts[1]
    set id $parts[2]
    echo "Importing $addr"
    terraform import -input=false -lock-timeout=30s "$addr" "$id" < /dev/null
end

9) Finally run terraform plan and verify that nothing is going to change.

Conclusion

That’s it! My code is now in Terraform and I can add/remove things and know that Terraform will control it.

I’m not sure why but I found the aztfexport tutorials all seemed to be a bit hard to understand so hopefully this gives you a good example of how to use it. If I’m honest, I’m not sure why I have to do manually steps to parse JSON and loop over all the resources to add them into a tfstate file - I thought there would be a command which simply merges two state files - but it doesn’t seem worth spending more time on as I’ve reached my end goal.

The rest of this post are some other variations on step 8 for other terminals. These haven’t been tested but will hopefully save you an AI Prompt!

Other Terminals (Untested - Converted with AI)

Bash

#!/bin/bash
MAPFILE="/PATH_TO_YOUR_REPO/TEMPRG/aztfexportResourceMapping.json"
MODULE_NAME="TEMPRG"

# Use jq to format "address resource_id" pairs
jq -r '. | to_entries[] | "module.'$MODULE_NAME'.\(.value.resource_type).\(.value.resource_name) \(.value.resource_id)"' "$MAPFILE" | while read -r addr id; do
    echo "Importing $addr..."
    terraform import -input=false -lock-timeout=30s "$addr" "$id" < /dev/null
done

PowerShell

$mapFile = "/PATH_TO_YOUR_REPO/TEMPRG/aztfexportResourceMapping.json"
$moduleName = "TEMPRG"

$mappings = Get-Content $mapFile | ConvertFrom-Json

foreach ($key in $mappings.PSObject.Properties.Name) {
    $resource = $mappings.$key
    $addr = "module.$moduleName.$($resource.resource_type).$($resource.resource_name)"
    $id = $resource.resource_id
    
    Write-Host "Importing $addr..."
    terraform import -input=false -lock-timeout=30s "$addr" "$id"
}