Need a clean, hardened Rocky Linux image in Azure — ready to go with your tools and configs? Here’s how to use Packer to build a Rocky image and then deploy it with cloud-init using Azure CLI.

Step 0: Install Azure CLI

Before deploying anything, make sure you have Azure CLI installed.

Linux/macOS:

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

Windows:

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

Login:

az login

This opens a browser window for authentication. Once done, you’re ready to deploy.

Step 1: Build a Custom Image with Packer

Create a Packer template with Azure as the target and make sure cloud-init is installed during provisioning.

Packer Template Example (rocky-azure.pkr.hcl):

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"
  location                          = "East US"
  os_type                           = "Linux"
  image_publisher                   = "OpenLogic"
  image_offer                       = "CentOS"
  image_sku                         = "8_2"
  vm_size                           = "Standard_B1s"
  build_resource_group_name         = "packer-temp"
}

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

  provisioner "shell" {
    inline = [
      "dnf install -y cloud-init",
      "systemctl enable cloud-init"
    ]
  }
}

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"

Build the Image:

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

Step 2: Prepare a Cloud-init Script

This will run the first time the VM boots and set things up.

cloud-init.yaml:

#cloud-config
hostname: rocky-demo
users:
  - name: devops
    sudo: ALL=(ALL) NOPASSWD:ALL
    groups: users, admin
    shell: /bin/bash
    ssh_authorized_keys:
      - ssh-rsa AAAA...your_key_here...

runcmd:
  - yum update -y
  - echo 'Cloud-init completed!' > /etc/motd

Step 3: Deploy the VM in Azure

Use the Azure CLI to deploy a VM from the managed image and inject the cloud-init file.

az vm create \
  --resource-group my-rg \
  --name rocky-vm \
  --image /subscriptions/<SUB_ID>/resourceGroups/packer-images/providers/Microsoft.Compute/images/rocky-image \
  --admin-username azureuser \
  --generate-ssh-keys \
  --custom-data cloud-init.yaml

Step 4: Verify Cloud-init Ran

ssh azureuser@<public-ip>
cat /etc/motd

You should see:

Cloud-init completed!

Recap

• Install Azure CLI and authenticate with az login
• Packer creates a reusable Rocky image with cloud-init preinstalled
• Cloud-init configures the VM at first boot using a YAML script
• Azure CLI deploys the VM and injects custom setup

By combining Packer and cloud-init, you ensure your Azure VMs are fast, consistent, and ready from the moment they boot.