Packer supports building VHDs in [Azure Resource Manager](https://azure.microsoft.com/en-us/documentation/articles/resource-group-overview/). Azure provides new users a [$200 credit for the first 30 days](https://azure.microsoft.com/en-us/free/); after which you will incur costs for VMs built and stored using Packer.
Unlike most Packer builders, the artifact produced by the ARM builder is a VHD (virtual hard disk), not a full virtual machine image. This means you will need to [perform some additional steps](https://github.com/Azure/packer-azure/issues/201) in order to launch a VM from your build artifact.
Azure uses a combination of OAuth and Active Directory to authorize requests to the ARM API. Learn how to [authorize access to ARM](/docs/builders/azure-setup.html).
The documentation below references command output from the [Azure CLI](https://azure.microsoft.com/en-us/documentation/articles/xplat-cli-install/).
## Configuration Reference
The following configuration options are available for building Azure images. In addition to the options listed here, a
[communicator](/docs/templates/communicator.html) can be configured for this
-`subscription_id` (string) Subscription under which the build will be performed. **The service principal specified in `client_id` must have full access to this subscription, unless build_resource_group_name option is specified in which case it needs to have owner access to the existing resource group specified in build_resource_group_name parameter.**
-`capture_container_name` (string) Destination container name. Essentially the "directory" where your VHD will be organized in Azure. The captured VHD's URL will be `https://<storage_account>.blob.core.windows.net/system/Microsoft.Compute/Images/<capture_container_name>/<capture_name_prefix>.xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.vhd`.
-`image_publisher` (string) PublisherName for your base image. See [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/) for details.
-`image_offer` (string) Offer for your base image. See [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/) for details.
-`image_sku` (string) SKU for your base image. See [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/) for details.
organized in Azure. The captured VHD's URL will be `https://<storage_account>.blob.core.windows.net/system/Microsoft.Compute/Images/<capture_container_name>/<capture_name_prefix>.xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.vhd`.
image name must not exist ahead of time, and will not be overwritten. If this value is set, the value
`managed_image_resource_group_name` must also be set. See [documentation](https://docs.microsoft.com/en-us/azure/storage/storage-managed-disks-overview#images)
image_publisher, image_offer, image_sku, or image_version. If this value is set, the value
`custom_managed_image_resource_group_name` must also be set. See [documentation](https://docs.microsoft.com/en-us/azure/storage/storage-managed-disks-overview#images)
-`custom_managed_image_resource_group_name` (string) Specify the source managed image's resource group used to use. If this
value is set, do not set image_publisher, image_offer, image_sku, or image_version. If this value is set, the
value `custom_managed_image_name` must also be set. See [documentation](https://docs.microsoft.com/en-us/azure/storage/storage-managed-disks-overview#images)
will only contain an OS disk. The number of additional disks and maximum size of a disk depends on the configuration of your VM. See [Windows](https://docs.microsoft.com/en-us/azure/virtual-machines/windows/about-disks-and-vhds) or [Linux](https://docs.microsoft.com/en-us/azure/virtual-machines/linux/about-disks-and-vhds) for more information.
For VHD builds the final artifacts will be named `PREFIX-dataDisk-<n>.UUID.vhd` and stored in the specified capture container along side the OS disk. The additional disks are included in the deployment template `PREFIX-vmTemplate.UUID`.
For Managed build the final artifacts are included in the managed image. The additional disk will have the same storage account type as the OS disk, as specified with the `managed_image_storage_account_type` setting.
Azure VMs should be deprovisioned at the end of every build. For Windows this means executing sysprep, and for Linux this means executing the waagent deprovision process.
Please refer to the Azure [examples](https://github.com/hashicorp/packer/tree/master/examples/azure) for complete examples showing the deprovision process.
In some circumstances the above isn't enough to reliably know that the sysprep is actually finished generalizing the image, the code below will wait for sysprep to write the image status in the registry and will exit after that. The possible states, in case you want to wait for another state, [are documented here](https://technet.microsoft.com/en-us/library/hh824815.aspx)
One solution is to set skip\_clean to true in the provisioner. This prevents Packer from cleaning up any helper scripts uploaded to the VM during the build.
The Azure builder attempts to pick default values that provide for a just works experience. These values can be changed by the user to more suitable values.
- The default user name is packer not root as in other builders. Most distros on Azure do not allow root to SSH to a VM hence the need for a non-root default user. Set the ssh\_username option to override the default value.
- The default VM size is Standard\_A1. Set the vm\_size option to override the default value.
- The default image version is latest. Set the image\_version option to override the default value.
- By default a temporary resource group will be created and destroyed as part of the build. If you do not have permissions to do so, use `build_resource_group_name` to specify an existing resource group to run the build in.
- Administrator Password: a random 32-character value using the *password alphabet*.
- Certificate: a 2,048-bit certificate used to secure WinRM communication. The certificate is valid for 24-hours, which starts roughly at invocation time.
- Certificate Password: a random 32-character value using the *password alphabet* used to protect the private key of the certificate.
- Compute Name: a random 15-character name prefixed with pkrvm; the name of the VM.
- Deployment Name: a random 15-character name prefixed with pkfdp; the name of the deployment.
- KeyVault Name: a random 15-character name prefixed with pkrkv.
- OS Disk Name: a random 15-character name prefixed with pkros.
- Resource Group Name: a random 33-character name prefixed with packer-Resource-Group-.
