anchor.diff:  more information on managed disks, see [Azure Managed Disks Overview](https://docs.microsoft.com/en-us/azure/virtual-machines/windows/managed-disks-overview).
   
   The difference between this builder and the `azure-arm` builder is that this
  -builder is able to build a managed disk image without launching an Azure VM 
  -instance. This can dramatically speed up image builds. It also allows for more
  -deterministic image content and enables some capabilities that are not possible
  -with the `azure-arm` builder.
  +builder is able to build a managed disk image without launching a new Azure VM
  +for every build, but instead use an already-running Azure VM. This can
  +dramatically speed up image builds. It also allows for more deterministic image
  +content and enables some capabilities that are not possible with the
  +`azure-arm` builder.
   
   > **This is an advanced builder** If you're just getting started with Packer,
   it is recommend to start with the [azure-arm builder](/docs/builders/azure-arm.html),
  
positive.code:     "client_id": "{{user `client_id`}}",
      "client_secret": "{{user `client_secret`}}",
      "subscription_id": "{{user `subscription_id`}}",
      
      "image_resource_id": "/subscriptions/{{user `subscription_id`}}/resourceGroups/{{user `resource_group`}}/providers/Microsoft.Compute/images/MyDebianOSImage-{{timestamp}}",
  
      "source": "credativ:Debian:9:latest"
  
negative.code: 
  ### Using a Service Principal
  Here is an example that creates a Debian image with updated packages. Specify
  all environment variables (`ARM_CLIENT_ID`, `ARM_CLIENT_SECRET`,
  `ARM_SUBSCRIPTION_ID`) to use a service principal.
  The identity you choose should have permission to create disks and images and also
  to update your VM.
  