How to Import an Azure Managed Image into Terraform

Import Azure Managed Image with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Azure Compute resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live Azure Managed Image to managed Terraform.

terraback scan all azure --subscription-id YOUR_ID

terraback azure import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = azurerm_image.base
  id = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/prod-rg/providers/Microsoft.Compute/images/base-image"
}

Example azurerm_image configuration

Here is a realistic Azure Managed Image block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "azurerm_image" "base" {
  name                = "base-image"
  location            = "eastus"
  resource_group_name = "prod-rg"

  os_disk {
    os_type         = "Linux"
    os_state        = "Generalized"
    managed_disk_id = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/prod-rg/providers/Microsoft.Compute/disks/base-os-disk"
    caching         = "ReadWrite"
  }
}

Gotchas when importing a Azure Managed Image

• azurerm_image is the legacy managed image; for new work consider Azure Compute Gallery (azurerm_shared_image), which is a different resource.
• Either source_virtual_machine_id or an os_disk block must be present; the source VM/disk it was captured from imports separately.
• os_disk.os_state (Generalized vs Specialized) and os_type are immutable and must match the existing image.
• Data disks are repeated data_disk blocks inside the image, each keyed by lun.

Doing it manually with terraform import

The native approach is to write the azurerm_image block by hand, then run terraform import azurerm_image.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other Azure resources