Spinning up clean, custom Rocky Linux VMs in Azure doesn’t have to involve manual configuration or portal clicks. With HashiCorp Packer, you can create, configure, and publish VM images to your Azure subscription automatically.

What You’ll Need

• Packer installed
• Azure CLI (az login)
• Azure subscription & resource group
• Azure Service Principal credentials

Step 1: Install Azure CLI

You need the Azure CLI to authenticate and manage resources.

On Linux/macOS:

curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash

On Windows:

Download and install from https://aka.ms/installazurecli

Step 2: Login to Azure

az login

This will open a browser window for you to authenticate your account.

Step 3: Set the Default Subscription (if you have more than one)

az account set --subscription "SUBSCRIPTION_NAME_OR_ID"

Step 4: Create a Resource Group for Images

az group create --name packer-images --location eastus

Step 5: Create a Service Principal for Packer

az ad sp create-for-rbac \
  --role="Contributor" \
  --scopes="/subscriptions/<your-subscription-id>" \
  --name "packer-service-principal"

This will return the client_id, client_secret, tenant_id, and subscription_id needed for your variables file.

Step 6: Write the Packer Template (rocky-azure.pkr.hcl)

variable "client_id" {}
variable "client_secret" {}
variable "tenant_id" {}
variable "subscription_id" {}

source "azure-arm" "rocky" {
  client_id       = var.client_id
  client_secret   = var.client_secret
  tenant_id       = var.tenant_id
  subscription_id = var.subscription_id

  managed_image_resource_group_name = "packer-images"
  managed_image_name                = "rocky-image"

  os_type             = "Linux"
  image_publisher     = "OpenLogic"
  image_offer         = "CentOS"
  image_sku           = "8_2"
  location            = "East US"
  vm_size             = "Standard_B1s"

  capture_container_name    = "images"
  capture_name_prefix       = "rocky-linux"
  build_resource_group_name = "packer-temp"
}

build {
  sources = ["source.azure-arm.rocky"]

  provisioner "shell" {
    inline = [
      "sudo dnf update -y",
      "sudo dnf install epel-release -y"
    ]
  }
}

Step 7: Create a Variables File (variables.pkrvars.hcl)

client_id       = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
client_secret   = "your-secret"
tenant_id       = "your-tenant-id"
subscription_id = "your-subscription-id"

Step 8: Run the Build

packer init .
packer build -var-file=variables.pkrvars.hcl .

Result

Your new custom Rocky Linux image will appear under your Azure resource group inside the Images section. From there, you can deploy it via the Azure Portal, CLI, Terraform, or ARM templates.

This process makes your infrastructure repeatable, versioned, and cloud-native. Use it to standardize dev environments or bake in security hardening from the start.