Azure Image Builder

From the author

Build Azure managed images and Azure Compute Gallery images with Packer. Use when creating custom images for Azure VMs.

— the description by HashiCorp

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a guide and configuration patterns for using Packer's azure-arm builder to create custom images for Azure. It covers the setup for both standard managed images and Azure Compute Gallery images, including authentication methods like service principals and managed identities, as well as common troubleshooting steps for image builds.

What it does

Configures Packer templates for Azure managed images
Defines settings for deploying images to the Azure Compute Gallery
Provides authentication patterns using service principals or managed identities
Includes HCL examples for defining OS types, VM sizes, and image locations
Outlines essential CLI commands for initializing, validating, and building images
Offers troubleshooting guidance for common authentication and provisioning errors

When to use it

When you need to automate the creation of standardized, pre-configured VM images for Azure
When managing custom image versions across multiple Azure regions via the Compute Gallery
When integrating image creation into a CI/CD pipeline for infrastructure deployment
When you need to apply security updates or custom software configurations to base OS images

Advantages

Enables infrastructure-as-code practices for virtual machine image management
Supports automated replication of images across different Azure regions
Reduces manual configuration time by automating OS updates and software installation
Ensures consistency across deployed virtual machine environments

Usage examples

“How do I configure a Packer template to build a custom Ubuntu image in Azure?”: The agent provides a HCL template using the azure-arm builder, showing how to specify the source image, VM size, and shell provisioners for updates.
“What is the process for publishing a custom image to the Azure Compute Gallery?”: The agent explains how to add the shared_image_gallery_destination block to your Packer configuration to define the gallery, image name, and replication regions.
“How can I authenticate Packer to Azure using a service principal?”: The agent provides the CLI commands to create a service principal with the Contributor role and the environment variables required for Packer authentication.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/hashicorp/azure-image-builder/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip azure-image-builder.zip -d .agents/skills

Documentation by HashiCorp

Build Azure managed images and Azure Compute Gallery images using Packer's azure-arm builder.

Reference: Azure ARM Builder

Note: Building Azure images incurs costs (compute, storage, data transfer). Builds typically take 15-45 minutes depending on provisioning and OS.

Basic Managed Image

packer {
  required_plugins {
    azure = {
      source  = "github.com/hashicorp/azure"
      version = "~> 2.0"
    }
  }
}

variable "client_id" {
  type      = string
  sensitive = true
}

variable "client_secret" {
  type      = string
  sensitive = true
}

variable "subscription_id" {
  type = string
}

variable "tenant_id" {
  type = string
}

variable "resource_group" {
  type    = string
  default = "packer-images-rg"
}

locals {
  timestamp = regex_replace(timestamp(), "[- TZ:]", "")
}

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

  managed_image_resource_group_name = var.resource_group
  managed_image_name                = "my-app-${local.timestamp}"

  os_type         = "Linux"
  image_publisher = "Canonical"
  image_offer     = "0001-com-ubuntu-server-jammy"
  image_sku       = "22_04-lts-gen2"

  location = "East US"
  vm_size  = "Standard_B2s"

  azure_tags = {
    Name      = "my-app"
    BuildDate = local.timestamp
  }
}

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

  provisioner "shell" {
    inline = [
      "sudo apt-get update",
      "sudo apt-get upgrade -y",
    ]
  }
}

Azure Compute Gallery

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

  os_type         = "Linux"
  image_publisher = "Canonical"
  image_offer     = "0001-com-ubuntu-server-jammy"
  image_sku       = "22_04-lts-gen2"

  location = "East US"
  vm_size  = "Standard_B2s"

  shared_image_gallery_destination {
    resource_group       = "gallery-rg"
    gallery_name         = "myImageGallery"
    image_name           = "ubuntu-webapp"
    image_version        = "1.0.${formatdate("YYYYMMDD", timestamp())}"
    replication_regions  = ["East US", "West US 2"]
    storage_account_type = "Standard_LRS"
  }
}

Authentication

Service Principal

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

# Set environment variables
export ARM_CLIENT_ID="<client-id>"
export ARM_CLIENT_SECRET="<client-secret>"
export ARM_SUBSCRIPTION_ID="<subscription-id>"
export ARM_TENANT_ID="<tenant-id>"

Managed Identity

source "azure-arm" "ubuntu" {
  use_azure_cli_auth = true
  subscription_id    = var.subscription_id
  # ... rest of configuration
}

Build Commands

# Set authentication
export ARM_CLIENT_ID="your-client-id"
export ARM_CLIENT_SECRET="your-client-secret"
export ARM_SUBSCRIPTION_ID="your-subscription-id"
export ARM_TENANT_ID="your-tenant-id"

# Initialize plugins
packer init .

# Validate template
packer validate .

# Build image
packer build .

Common Issues

Authentication Failed

Verify service principal credentials
Ensure Contributor role on resource group
Check subscription and tenant IDs

Compute Gallery Version Exists

Image versions are immutable
Use unique version numbers with date/build number
Cannot overwrite existing versions

Timeout During Provisioning

Check network connectivity from build VM
Verify NSG rules allow required traffic
Increase timeout if needed

References

Files

ATTRIBUTION.mdAdded by AutoGineer903 B
LICENSELicence file added by AutoGineer16.3 KiB
SKILL.md4.1 KiB

SKILL.md