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Packer can create Azure virtual machine images through variety of ways depending on the strategy that you want to use for building the images.

  • Official
  • HCP Ready

Updated 6 months ago

ARM

Type: azure-arm Artifact BuilderId: Azure.ResourceManagement.VMImage

Packer supports building Virtual Hard Disks (VHDs) and Managed Images in Azure Resource Manager. Azure provides new users a $200 credit for the first 30 days; after which you will incur costs for VMs built and stored using Packer.

Azure uses a combination of OAuth and Active Directory to authorize requests to the ARM API. Learn how to authorize access to ARM.

The documentation below references command output from the Azure CLI.

Configuration Reference

There are many configuration options available for the builder. We'll start with authentication parameters, then go over the Azure ARM builder specific options. In addition to the options listed here, a communicator can be configured for this builder.

Azure ARM builder specific options

The Azure builder can create either a VHD, managed image or create a Shared Image Gallery. If you are creating a VHD, you must start with a VHD. Likewise, if you want to create a managed image you must start with a managed image. Managed images can also be published to shared image galleries, but a managed image definition is not required to publish to a gallery.

Required:

  • image_publisher (string) - Name of the publisher to use for your base image (Azure Marketplace Images only). See documentation for details.

    CLI example az vm image list-publishers --location westus

  • image_offer (string) - Name of the publisher's offer to use for your base image (Azure Marketplace Images only). See documentation for details.

    CLI example az vm image list-offers --location westus --publisher Canonical

  • image_sku (string) - SKU of the image offer to use for your base image (Azure Marketplace Images only). See documentation for details.

    CLI example az vm image list-skus --location westus --publisher Canonical --offer UbuntuServer

  • image_url (string) - URL to a custom VHD to use for your base image. If this value is set, image_publisher, image_offer, image_sku, or image_version should not be set.

  • custom_managed_image_name (string) - Name of a custom managed image to use for your base image. If this value is set, do not set image_publisher, image_offer, image_sku, or image_version. If this value is set, the option custom_managed_image_resource_group_name must also be set. See documentation to learn more about managed images.

  • custom_managed_image_resource_group_name (string) - Name of a custom managed image's resource group to use for your base image. If this value is set, image_publisher, image_offer, image_sku, or image_version should not be set. If this value is set, the option custom_managed_image_name must also be set. See documentation to learn more about managed images.

When creating a VHD the following additional options are required:

  • 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.

  • capture_name_prefix (string) - VHD prefix. The final artifacts will be named PREFIX-osDisk.UUID and PREFIX-vmTemplate.UUID.

  • resource_group_name (string) - Resource group under which the final artifact will be stored.

  • storage_account (string) - Storage account under which the final artifact will be stored.

When creating a managed image the following additional options are required:

  • managed_image_name (string) - Specify the managed image name where the result of the Packer build will be saved. The 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 to learn more about managed images.

  • managed_image_resource_group_name (string) - Specify the managed image resource group name where the result of the Packer build will be saved. The resource group must already exist. If this value is set, the value managed_image_name must also be set. See documentation to learn more about managed images.

Creating a managed image using a Shared Gallery image as the source can be achieved by specifying the shared_image_gallery configuration option.

Resource Group Usage

The Azure builder can either provision resources into a new resource group that it controls (default) or an existing one. The advantage of using a packer defined resource group is that failed resource cleanup is easier because you can simply remove the entire resource group, however this means that the provided credentials must have permission to create and remove resource groups. By using an existing resource group you can scope the provided credentials to just this group, however failed builds are more likely to leave unused artifacts.

To have Packer create a resource group you must provide:

  • location (string) Azure datacenter in which your VM will build.

    CLI example az account list-locations

and optionally:

  • temp_resource_group_name (string) name assigned to the temporary resource group created during the build. If this value is not set, a random value will be assigned. This resource group is deleted at the end of the build.

To use an existing resource group you must provide:

  • build_resource_group_name (string) - Specify an existing resource group to run the build in.

Providing temp_resource_group_name or location in combination with build_resource_group_name is not allowed.

Optional:

  • user_assigned_managed_identities ([]string) - A list of one or more fully-qualified resource IDs of user assigned managed identities to be configured on the VM. See documentation for how to acquire tokens within the VM. To assign a user assigned managed identity to a VM, the provided account or service principal must have Managed Identity Operator and Virtual Machine Contributor role assignments.

  • capture_name_prefix (string) - VHD prefix.

  • capture_container_name (string) - Destination container name.

  • shared_image_gallery (SharedImageGallery) - Use a Shared Gallery image as the source for this build. VHD targets are incompatible with this build type - the target must be a Managed Image. When using shared_image_gallery as a source, image_publisher, image_offer, image_sku, image_version, and custom_managed_image_name should not be set.

    In JSON

    "shared_image_gallery": {
    "subscription": "00000000-0000-0000-0000-00000000000",
    "resource_group": "ResourceGroup",
    "gallery_name": "GalleryName",
    "image_name": "ImageName",
    "image_version": "1.0.0",
}
"managed_image_name": "TargetImageName",
"managed_image_resource_group_name": "TargetResourceGroup"

    In HCL2

    shared_image_gallery {
    subscription = "00000000-0000-0000-0000-00000000000"
    resource_group = "ResourceGroup"
    gallery_name = "GalleryName"
    image_name = "ImageName"
    image_version = "1.0.0"
}
managed_image_name = "TargetImageName"
managed_image_resource_group_name = "TargetResourceGroup"

  • shared_image_gallery_destination (SharedImageGalleryDestination) - The name of the Shared Image Gallery under which the managed image will be published as Shared Gallery Image version.

    Following is an example.

    In JSON

    "shared_image_gallery_destination": {
    "subscription": "00000000-0000-0000-0000-00000000000",
    "resource_group": "ResourceGroup",
    "gallery_name": "GalleryName",
    "image_name": "ImageName",
    "image_version": "1.0.0",
    "replication_regions": ["regionA", "regionB", "regionC"],
    "storage_account_type": "Standard_LRS"
}
"managed_image_name": "TargetImageName",
"managed_image_resource_group_name": "TargetResourceGroup"

    In HCL2

    shared_image_gallery_destination {
    subscription = "00000000-0000-0000-0000-00000000000"
    resource_group = "ResourceGroup"
    gallery_name = "GalleryName"
    image_name = "ImageName"
    image_version = "1.0.0"
    replication_regions = ["regionA", "regionB", "regionC"]
    storage_account_type = "Standard_LRS"
}
managed_image_name = "TargetImageName"
managed_image_resource_group_name = "TargetResourceGroup"

  • shared_image_gallery_timeout (duration string | ex: "1h5m2s") - How long to wait for an image to be published to the shared image gallery before timing out. If your Packer build is failing on the Publishing to Shared Image Gallery step with the error Original Error: context deadline exceeded, but the image is present when you check your Azure dashboard, then you probably need to increase this timeout from its default of "60m" (valid time units include s for seconds, m for minutes, and h for hours.)

  • shared_gallery_image_version_end_of_life_date (string) - The end of life date (2006-01-02T15:04:05.99Z) of the gallery Image Version. This property can be used for decommissioning purposes.

  • shared_image_gallery_replica_count (int64) - The number of replicas of the Image Version to be created per region. Replica count must be between 1 and 100, but 50 replicas should be sufficient for most use cases. When using shallow replication use_shallow_replication=true the value can only be 1.

  • shared_gallery_image_version_exclude_from_latest (bool) - If set to true, Virtual Machines deployed from the latest version of the Image Definition won't use this Image Version.

  • image_version (string) - Specify a specific version of an OS to boot from. Defaults to latest. There may be a difference in versions available across regions due to image synchronization latency. To ensure a consistent version across regions set this value to one that is available in all regions where you are deploying.

    CLI example az vm image list --location westus --publisher Canonical --offer UbuntuServer --sku 16.04.0-LTS --all

  • location (string) - Azure datacenter in which your VM will build.

  • vm_size (string) - Size of the VM used for building. This can be changed when you deploy a VM from your VHD. See pricing information. Defaults to Standard_A1.

    CLI example az vm list-sizes --location westus

  • spot (Spot) - If set use a spot instance during build; spot configuration settings only apply to the virtual machine launched by Packer and will not be persisted on the resulting image artifact.

    Following is an example.

    In JSON

    "spot": {
    "eviction_policy": "Delete",
       "max_price": "0.4",
}

    In HCL2

    spot {
    eviction_policy = "Delete"
    max_price = "0.4"
}

  • managed_image_resource_group_name (string) - Specify the managed image resource group name where the result of the Packer build will be saved. The resource group must already exist. If this value is set, the value managed_image_name must also be set. See documentation to learn more about managed images.

  • managed_image_name (string) - Specify the managed image name where the result of the Packer build will be saved. The 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 to learn more about managed images.

  • managed_image_storage_account_type (string) - Specify the storage account type for a managed image. Valid values are Standard_LRS and Premium_LRS. The default is Standard_LRS.

  • managed_image_os_disk_snapshot_name (string) - If managed_image_os_disk_snapshot_name is set, a snapshot of the OS disk is created with the same name as this value before the VM is captured.

  • managed_image_data_disk_snapshot_prefix (string) - If managed_image_data_disk_snapshot_prefix is set, snapshot of the data disk(s) is created with the same prefix as this value before the VM is captured.

  • keep_os_disk (bool) - If keep_os_disk is set, the OS disk is not deleted. The default is false.

  • managed_image_zone_resilient (bool) - Store the image in zone-resilient storage. You need to create it in a region that supports availability zones.

  • azure_tags (map[string]string) - Name/value pair tags to apply to every resource deployed i.e. Resource Group, VM, NIC, VNET, Public IP, KeyVault, etc. The user can define up to 15 tags. Tag names cannot exceed 512 characters, and tag values cannot exceed 256 characters.

  • azure_tag ([]{name string, value string}) - Same as azure_tags but defined as a singular repeatable block containing a name and a value field. In HCL2 mode the dynamic_block will allow you to create those programatically.

  • resource_group_name (string) - Resource group under which the final artifact will be stored.

  • storage_account (string) - Storage account under which the final artifact will be stored.

  • temp_compute_name (string) - temporary name assigned to the VM. If this value is not set, a random value will be assigned. Knowing the resource group and VM name allows one to execute commands to update the VM during a Packer build, e.g. attach a resource disk to the VM.

  • temp_nic_name (string) - temporary name assigned to the Nic. If this value is not set, a random value will be assigned. Being able to assign a custom nicname could ease deployment if naming conventions are used.

  • temp_resource_group_name (string) - name assigned to the temporary resource group created during the build. If this value is not set, a random value will be assigned. This resource group is deleted at the end of the build.

  • build_resource_group_name (string) - Specify an existing resource group to run the build in.

  • build_key_vault_name (string) - Specify an existing key vault to use for uploading the certificate for the instance to connect.

  • build_key_vault_secret_name (string) - Specify the secret name to use for the certificate created in the key vault.

  • build_key_vault_sku (string) - Specify the KeyVault SKU to create during the build. Valid values are standard or premium. The default value is standard.

  • disk_encryption_set_id (string) - Specify the Disk Encryption Set ID to use to encrypt the OS and data disks created with the VM during the build Only supported when publishing to Shared Image Galleries, without a managed image The disk encryption set ID can be found in the properties tab of a disk encryption set on the Azure Portal, and is labeled as its resource ID https://learn.microsoft.com/en-us/azure/virtual-machines/image-version-encryption

  • private_virtual_network_with_public_ip (bool) - This value allows you to set a virtual_network_name and obtain a public IP. If this value is not set and virtual_network_name is defined Packer is only allowed to be executed from a host on the same subnet / virtual network.

  • virtual_network_name (string) - Use a pre-existing virtual network for the VM. This option enables private communication with the VM, no public IP address is used or provisioned (unless you set private_virtual_network_with_public_ip).

  • virtual_network_subnet_name (string) - If virtual_network_name is set, this value may also be set. If virtual_network_name is set, and this value is not set the builder attempts to determine the subnet to use with the virtual network. If the subnet cannot be found, or it cannot be disambiguated, this value should be set.

  • virtual_network_resource_group_name (string) - If virtual_network_name is set, this value may also be set. If virtual_network_name is set, and this value is not set the builder attempts to determine the resource group containing the virtual network. If the resource group cannot be found, or it cannot be disambiguated, this value should be set.

  • custom_data_file (string) - Specify a file containing custom data to inject into the cloud-init process. The contents of the file are read and injected into the ARM template. The custom data will be passed to cloud-init for processing at the time of provisioning. See documentation to learn more about custom data, and how it can be used to influence the provisioning process.

  • custom_data (string) - Specify a Base64-encode custom data to apply when launching the instance. Note that you need to be careful about escaping characters due to the templates being JSON. The custom data will be passed to cloud-init for processing at the time of provisioning. See documentation to learn more about custom data, and how it can be used to influence the provisioning process.

  • user_data_file (string) - Specify a file containing user data to inject into the cloud-init process. The contents of the file are read and injected into the ARM template. The user data will be available from the provision until the vm is deleted. Any application on the virtual machine can access the user data from the Azure Instance Metadata Service (IMDS) after provision. See documentation to learn more about user data.

  • user_data (string) - Specify a Base64-encode user data to apply Note that you need to be careful about escaping characters due to the templates being JSON. The user data will be available from the provision until the vm is deleted. Any application on the virtual machine can access the user data from the Azure Instance Metadata Service (IMDS) after provision. See documentation to learn more about user data.

  • custom_script (string) - Used for running a script on VM provision during the image build The following example executes the contents of the file specified by user_data_file:

    custom_script   = "powershell -ExecutionPolicy Unrestricted -NoProfile -NonInteractive -Command \"$userData = (Invoke-RestMethod -Headers @{Metadata=$true} -Method GET -Uri http://169.254.169.254/metadata/instance/compute/userData?api-version=2021-01-01$([char]38)format=text); $contents = [System.Text.Encoding]::UTF8.GetString([Convert]::FromBase64String($userData)); set-content -path c:\\Windows\\Temp\\userdata.ps1 -value $contents; . c:\\Windows\\Temp\\userdata.ps1;\""
user_data_file  = "./scripts/userdata.ps1"

    Specify a command to inject into the CustomScriptExtension, to run on startup on Windows builds, before the communicator attempts to connect See documentation to learn more.

  • plan_info (PlanInformation) - Used for creating images from Marketplace images. Please refer to Deploy an image with Marketplace terms for more details. Not all Marketplace images support programmatic deployment, and support is controlled by the image publisher.

    An example plan_info object is defined below.

    {
  "plan_info": {
      "plan_name": "rabbitmq",
      "plan_product": "rabbitmq",
      "plan_publisher": "bitnami"
  }
}

    plan_name (string) - The plan name, required. plan_product (string) - The plan product, required. plan_publisher (string) - The plan publisher, required. plan_promotion_code (string) - Some images accept a promotion code, optional.

    Images created from the Marketplace with plan_info must specify plan_info whenever the image is deployed. The builder automatically adds tags to the image to ensure this information is not lost. The following tags are added.

    1.  PlanName
2.  PlanProduct
3.  PlanPublisher
4.  PlanPromotionCode

  • polling_duration_timeout (duration string | ex: "1h5m2s") - The default PollingDuration for azure is 15mins, this property will override that value. If your Packer build is failing on the ARM deployment step with the error Original Error: context deadline exceeded, then you probably need to increase this timeout from its default of "15m" (valid time units include s for seconds, m for minutes, and h for hours.)

  • os_type (string) - If either Linux or Windows is specified Packer will automatically configure authentication credentials for the provisioned machine. For Linux this configures an SSH authorized key. For Windows this configures a WinRM certificate.

  • winrm_expiration_time (duration string | ex: "1h5m2s") - A time duration with which to set the WinRM certificate to expire This only works for Windows builds (valid time units include s for seconds, m for minutes, and h for hours.)

  • temp_os_disk_name (string) - temporary name assigned to the OSDisk. If this value is not set, a random value will be assigned. Being able to assign a custom osDiskName could ease deployment if naming conventions are used.

  • os_disk_size_gb (int32) - Specify the size of the OS disk in GB (gigabytes). Values of zero or less than zero are ignored.

  • disk_additional_size ([]int32) - The size(s) of any additional hard disks for the VM in gigabytes. If this is not specified then the VM 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 or Linux 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.

  • disk_caching_type (string) - Specify the disk caching type. Valid values are None, ReadOnly, and ReadWrite. The default value is ReadWrite.

  • allowed_inbound_ip_addresses ([]string) - Specify the list of IP addresses and CIDR blocks that should be allowed access to the VM. If provided, an Azure Network Security Group will be created with corresponding rules and be bound to the subnet of the VM. Providing allowed_inbound_ip_addresses in combination with virtual_network_name is not allowed.

  • boot_diag_storage_account (string) - Specify storage to store Boot Diagnostics -- Enabling this option will create 2 Files in the specified storage account. (serial console log & screehshot file) once the build is completed, it has to be removed manually. see here for more info

  • custom_resource_build_prefix (string) - specify custom azure resource names during build limited to max 10 characters this will set the prefix for the resources. The actuall resource names will be custom_resource_build_prefix + resourcetype + 5 character random alphanumeric string

  • license_type (string) - Specify a license type for the build VM to enable Azure Hybrid Benefit. If not set, Pay-As-You-Go license model (default) will be used. Valid values are:

    For Windows:

    • Windows_Client
    • Windows_Server

    For Linux:

    • RHEL_BYOS
    • SLES_BYOS

    Refer to the following documentation for more information about Hybrid Benefit: Windows or Linux

  • secure_boot_enabled (bool) - Specifies if Secure Boot and Trusted Launch is enabled for the Virtual Machine.

  • encryption_at_host (*bool) - Specifies if Encryption at host is enabled for the Virtual Machine. Requires enabling encryption at host in the Subscription read more here

  • vtpm_enabled (bool) - Specifies if vTPM (virtual Trusted Platform Module) and Trusted Launch is enabled for the Virtual Machine.

  • async_resourcegroup_delete (bool) - If you want packer to delete the temporary resource group asynchronously set this value. It's a boolean value and defaults to false. Important Setting this true means that your builds are faster, however any failed deletes are not reported.

  • cloud_environment_name (string) - One of Public, China, or USGovernment. Defaults to Public. Long forms such as USGovernmentCloud and AzureUSGovernmentCloud are also supported.

  • metadata_host (string) - The Hostname of the Azure Metadata Service (for example management.azure.com), used to obtain the Cloud Environment when using a Custom Azure Environment. This can also be sourced from the ARM_METADATA_HOST Environment Variable. Note: CloudEnvironmentName must be set to the requested environment name in the list of available environments held in the metadata_host.

  • client_id (string) - The application ID of the AAD Service Principal. Requires either client_secret, client_cert_path or client_jwt to be set as well.

  • client_secret (string) - A password/secret registered for the AAD SP.

  • client_cert_path (string) - The path to a PKCS#12 bundle (.pfx file) to be used as the client certificate that will be used to authenticate as the specified AAD SP.

  • client_cert_password (string) - The password for decrypting the client certificate bundle.

  • client_jwt (string) - A JWT bearer token for client auth (RFC 7523, Sec. 2.2) that will be used to authenticate the AAD SP. Provides more control over token the expiration when using certificate authentication than when using client_cert_path.

  • object_id (string) - The object ID for the AAD SP. Optional, will be derived from the oAuth token if left empty.

  • tenant_id (string) - The Active Directory tenant identifier with which your client_id and subscription_id are associated. If not specified, tenant_id will be looked up using subscription_id.

  • subscription_id (string) - The subscription to use.

  • use_azure_cli_auth (bool) - Flag to use Azure CLI authentication. Defaults to false. CLI auth will use the information from an active az login session to connect to Azure and set the subscription id and tenant id associated to the signed in account. If enabled, it will use the authentication provided by the az CLI. Azure CLI authentication will use the credential marked as isDefault and can be verified using az account show. Works with normal authentication (az login) and service principals (az login --service-principal --username APP_ID --password PASSWORD --tenant TENANT_ID). Ignores all other configurations if enabled.

  • skip_create_image (bool) - Skip creating the image. Useful for setting to true during a build test stage. Defaults to false.

Shared Image Gallery

The shared_image_gallery block is available for building a new image from a private or community shared imaged gallery owned gallery.

  • subscription (string) - Subscription

  • resource_group (string) - Resource Group

  • gallery_name (string) - Gallery Name

  • image_name (string) - Image Name

  • image_version (string) - Specify a specific version of an OS to boot from. Defaults to latest. There may be a difference in versions available across regions due to image synchronization latency. To ensure a consistent version across regions set this value to one that is available in all regions where you are deploying.

  • community_gallery_image_id (string) - Id of the community gallery image : /CommunityGalleries/{galleryUniqueName}/Images/{img}[/Versions/{}] (Versions part is optional)

  • direct_shared_gallery_image_id (string) - Id of the direct shared gallery image : /sharedGalleries/{galleryUniqueName}/Images/{img}[/Versions/{}] (Versions part is optional)

Shared Image Gallery Destination

The shared_image_gallery_destination block is available for publishing a new image version to an existing shared image gallery.

  • subscription (string) - Sig Destination Subscription

  • resource_group (string) - Sig Destination Resource Group

  • gallery_name (string) - Sig Destination Gallery Name

  • image_name (string) - Sig Destination Image Name

  • image_version (string) - Sig Destination Image Version

  • replication_regions ([]string) - A list of regions to replicate the image version in, by default the build location will be used as a replication region (the build location is either set in the location field, or the location of the resource group used in build_resource_group_name will be included. Can not contain any region but the build region when using shallow replication

  • storage_account_type (string) - Specify a storage account type for the Shared Image Gallery Image Version. Defaults to Standard_LRS. Accepted values are Standard_LRS, Standard_ZRS and Premium_LRS

  • specialized (bool) - Set to true if publishing to a Specialized Gallery, this skips a call to set the build VM's OS state as Generalized

  • use_shallow_replication (bool) - Setting a shared_image_gallery_replica_count or any replication_regions is unnecessary for shallow builds, as they can only replicate to the build region and must have a replica count of 1 Refer to Shallow Replication for details on when to use shallow replication mode.

Spot

The spot block is available to use a spot instance during build.

  • eviction_policy (virtualmachines.VirtualMachineEvictionPolicyTypes) - Specify eviction policy for spot instance: "Deallocate" or "Delete". If this is set, a spot instance will be used.

  • max_price (float32) - How much should the VM cost maximally per hour. Specify -1 (or do not specify) to not evict based on price.

Build Shared Information Variables

This builder generates data that are shared with provisioner and post-processor via build function of template engine for JSON and contextual variables for HCL2.

The generated variables available for this builder are:

  • SourceImageName - The full name of the source image used in the deployment. When using shared images the resulting name will point to the actual source used to create the said version. building the AMI.

Usage example:

HCL2

// When accessing one of these variables from inside the builder, you need to
// use the golang templating syntax. This is due to an architectural quirk that
// won't be easily resolvable until legacy json templates are deprecated:

{
source "azure-arm" "basic-example" {
  os_type = "Linux"
  image_publisher = "Canonical"
  image_offer = "UbuntuServer"
  image_sku = "14.04.4-LTS"
}

// when accessing one of the variables from a provisioner or post-processor, use
// hcl-syntax
post-processor "manifest" {
    output = "manifest.json"
    strip_path = true
    custom_data = {
        source_image_name = "${build.SourceImageName}"
    }
}

JSON

"post-processors": [
  {
    "type": "manifest",
    "output": "manifest.json",
    "strip_path": true,
    "custom_data": {
      "source_image_name": "{{ build `SourceImageName` }}"
    }
  }
]

Communicator Config

In addition to the builder options, a communicator may also be defined:

  • communicator (string) - Packer currently supports three kinds of communicators:

    • none - No communicator will be used. If this is set, most provisioners also can't be used.

    • ssh - An SSH connection will be established to the machine. This is usually the default.

    • winrm - A WinRM connection will be established.

    In addition to the above, some builders have custom communicators they can use. For example, the Docker builder has a "docker" communicator that uses docker exec and docker cp to execute scripts and copy files.

  • pause_before_connecting (duration string | ex: "1h5m2s") - We recommend that you enable SSH or WinRM as the very last step in your guest's bootstrap script, but sometimes you may have a race condition where you need Packer to wait before attempting to connect to your guest.

    If you end up in this situation, you can use the template option pause_before_connecting. By default, there is no pause. For example if you set pause_before_connecting to 10m Packer will check whether it can connect, as normal. But once a connection attempt is successful, it will disconnect and then wait 10 minutes before connecting to the guest and beginning provisioning.

  • ssh_host (string) - The address to SSH to. This usually is automatically configured by the builder.

  • ssh_port (int) - The port to connect to SSH. This defaults to 22.

  • ssh_username (string) - The username to connect to SSH with. Required if using SSH.

  • ssh_password (string) - A plaintext password to use to authenticate with SSH.

  • ssh_ciphers ([]string) - This overrides the value of ciphers supported by default by Golang. The default value is [ "aes128-gcm@openssh.com", "chacha20-poly1305@openssh.com", "aes128-ctr", "aes192-ctr", "aes256-ctr", ]

    Valid options for ciphers include: "aes128-ctr", "aes192-ctr", "aes256-ctr", "aes128-gcm@openssh.com", "chacha20-poly1305@openssh.com", "arcfour256", "arcfour128", "arcfour", "aes128-cbc", "3des-cbc",

  • ssh_clear_authorized_keys (bool) - If true, Packer will attempt to remove its temporary key from ~/.ssh/authorized_keys and /root/.ssh/authorized_keys. This is a mostly cosmetic option, since Packer will delete the temporary private key from the host system regardless of whether this is set to true (unless the user has set the -debug flag). Defaults to "false"; currently only works on guests with sed installed.

  • ssh_key_exchange_algorithms ([]string) - If set, Packer will override the value of key exchange (kex) algorithms supported by default by Golang. Acceptable values include: "curve25519-sha256@libssh.org", "ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521", "diffie-hellman-group14-sha1", and "diffie-hellman-group1-sha1".

  • ssh_certificate_file (string) - Path to user certificate used to authenticate with SSH. The ~ can be used in path and will be expanded to the home directory of current user.

  • ssh_pty (bool) - If true, a PTY will be requested for the SSH connection. This defaults to false.

  • ssh_timeout (duration string | ex: "1h5m2s") - The time to wait for SSH to become available. Packer uses this to determine when the machine has booted so this is usually quite long. Example value: 10m. This defaults to 5m, unless ssh_handshake_attempts is set.

  • ssh_disable_agent_forwarding (bool) - If true, SSH agent forwarding will be disabled. Defaults to false.

  • ssh_handshake_attempts (int) - The number of handshakes to attempt with SSH once it can connect. This defaults to 10, unless a ssh_timeout is set.

  • ssh_bastion_host (string) - A bastion host to use for the actual SSH connection.

  • ssh_bastion_port (int) - The port of the bastion host. Defaults to 22.

  • ssh_bastion_agent_auth (bool) - If true, the local SSH agent will be used to authenticate with the bastion host. Defaults to false.

  • ssh_bastion_username (string) - The username to connect to the bastion host.

  • ssh_bastion_password (string) - The password to use to authenticate with the bastion host.

  • ssh_bastion_interactive (bool) - If true, the keyboard-interactive used to authenticate with bastion host.

  • ssh_bastion_private_key_file (string) - Path to a PEM encoded private key file to use to authenticate with the bastion host. The ~ can be used in path and will be expanded to the home directory of current user.

  • ssh_bastion_certificate_file (string) - Path to user certificate used to authenticate with bastion host. The ~ can be used in path and will be expanded to the home directory of current user.

  • ssh_file_transfer_method (string) - scp or sftp - How to transfer files, Secure copy (default) or SSH File Transfer Protocol.

    NOTE: Guests using Windows with Win32-OpenSSH v9.1.0.0p1-Beta, scp (the default protocol for copying data) returns a a non-zero error code since the MOTW cannot be set, which cause any file transfer to fail. As a workaround you can override the transfer protocol with SFTP instead ssh_file_transfer_protocol = "sftp".

  • ssh_proxy_host (string) - A SOCKS proxy host to use for SSH connection

  • ssh_proxy_port (int) - A port of the SOCKS proxy. Defaults to 1080.

  • ssh_proxy_username (string) - The optional username to authenticate with the proxy server.

  • ssh_proxy_password (string) - The optional password to use to authenticate with the proxy server.

  • ssh_keep_alive_interval (duration string | ex: "1h5m2s") - How often to send "keep alive" messages to the server. Set to a negative value (-1s) to disable. Example value: 10s. Defaults to 5s.

  • ssh_read_write_timeout (duration string | ex: "1h5m2s") - The amount of time to wait for a remote command to end. This might be useful if, for example, packer hangs on a connection after a reboot. Example: 5m. Disabled by default.

  • ssh_remote_tunnels ([]string) -

  • ssh_local_tunnels ([]string) -

  • ssh_private_key_file (string) - Path to a PEM encoded private key file to use to authenticate with SSH. The ~ can be used in path and will be expanded to the home directory of current user.

Basic Example

Here is a basic example for Azure.

HCL2

source "azure-arm" "basic-example" {
  client_id = "fe354398-d7sf-4dc9-87fd-c432cd8a7e09"
  client_secret = "keepitsecret&#*$"
  resource_group_name = "packerdemo"
  storage_account = "virtualmachines"
  subscription_id = "44cae533-4247-4093-42cf-897ded6e7823"
  tenant_id = "de39842a-caba-497e-a798-7896aea43218"

  capture_container_name = "images"
  capture_name_prefix = "packer"

  os_type = "Linux"
  image_publisher = "Canonical"
  image_offer = "UbuntuServer"
  image_sku = "14.04.4-LTS"

  azure_tags = {
    dept = "engineering"
  }

  location = "West US"
  vm_size = "Standard_A2"
}

build {
  sources = ["sources.azure-arm.basic-example"]
}

JSON

{
  "type": "azure-arm",

  "client_id": "fe354398-d7sf-4dc9-87fd-c432cd8a7e09",
  "client_secret": "keepitsecret&#*$",
  "resource_group_name": "packerdemo",
  "storage_account": "virtualmachines",
  "subscription_id": "44cae533-4247-4093-42cf-897ded6e7823",
  "tenant_id": "de39842a-caba-497e-a798-7896aea43218",

  "capture_container_name": "images",
  "capture_name_prefix": "packer",

  "os_type": "Linux",
  "image_publisher": "Canonical",
  "image_offer": "UbuntuServer",
  "image_sku": "14.04.4-LTS",

  "azure_tags": {
    "dept": "engineering"
  },

  "location": "West US",
  "vm_size": "Standard_A2"
}

Deprovision

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 example folder for complete examples showing the deprovision process.

Windows

The following provisioner snippet shows how to sysprep a Windows VM. Deprovision should be the last operation executed by a build. 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

JSON

{
  "provisioners": [
    {
      "type": "powershell",
      "inline": [
        "# If Guest Agent services are installed, make sure that they have started.",
        "foreach ($service in Get-Service -Name RdAgent, WindowsAzureTelemetryService, WindowsAzureGuestAgent -ErrorAction SilentlyContinue) { while ((Get-Service $service.Name).Status -ne 'Running') { Start-Sleep -s 5 } }",

        "& $env:SystemRoot\\System32\\Sysprep\\Sysprep.exe /oobe /generalize /quiet /quit /mode:vm",
        "while($true) { $imageState = Get-ItemProperty HKLM:\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Setup\\State | Select ImageState; if($imageState.ImageState -ne 'IMAGE_STATE_GENERALIZE_RESEAL_TO_OOBE') { Write-Output $imageState.ImageState; Start-Sleep -s 10  } else { break } }"
      ]
    }
  ]
}

HCL2

provisioner "powershell" {
   inline = [
        "# If Guest Agent services are installed, make sure that they have started.",
        "foreach ($service in Get-Service -Name RdAgent, WindowsAzureTelemetryService, WindowsAzureGuestAgent -ErrorAction SilentlyContinue) { while ((Get-Service $service.Name).Status -ne 'Running') { Start-Sleep -s 5 } }",

        "& $env:SystemRoot\\System32\\Sysprep\\Sysprep.exe /oobe /generalize /quiet /quit /mode:vm",
        "while($true) { $imageState = Get-ItemProperty HKLM:\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Setup\\State | Select ImageState; if($imageState.ImageState -ne 'IMAGE_STATE_GENERALIZE_RESEAL_TO_OOBE') { Write-Output $imageState.ImageState; Start-Sleep -s 10  } else { break } }"
   ]
}

The Windows Guest Agent participates in the Sysprep process. The agent must be fully installed before the VM can be sysprep'ed. To ensure this is true all agent services must be running before executing sysprep.exe. The above JSON snippet shows one way to do this in the PowerShell provisioner. This snippet is only required if the VM is configured to install the agent, which is the default. To learn more about disabling the Windows Guest Agent please see Install the VM Agent.

Please note that sysprep can get stuck in infinite loops if it is not configured correctly -- for example, if it is waiting for a reboot that you never perform.

Linux

The following provisioner snippet shows how to deprovision a Linux VM. Deprovision should be the last operation executed by a build.

JSON

{
  "provisioners": [
    {
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'",
      "inline": [
        "/usr/sbin/waagent -force -deprovision+user && export HISTSIZE=0 && sync"
      ],
      "inline_shebang": "/bin/sh -x",
      "type": "shell"
    }
  ]
}

HCL2

provisioner "shell" {
   execute_command = "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'"
   inline = [
        "/usr/sbin/waagent -force -deprovision+user && export HISTSIZE=0 && sync"
   ]
   inline_shebang = "/bin/sh -x"
}

To learn more about the Linux deprovision process please see WALinuxAgent's README.

skip_clean

Customers have reported issues with the deprovision process where the builder hangs. The error message is similar to the following.

Build 'azure-arm' errored: Retryable error: Error removing temporary script at /tmp/script_9899.sh: ssh: handshake failed: EOF

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.

Defaults

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.

Implementation

Warning! This is an advanced topic. You do not need to understand the implementation to use the Azure builder.

The Azure builder uses ARM templates to deploy resources. ARM templates allow you to express the what without having to express the how.

The Azure builder works under the assumption that it creates everything it needs to execute a build. When the build has completed it simply deletes the resource group to cleanup any runtime resources. Resource groups are named using the form packer-Resource-Group-<random>. The value <random> is a random value that is generated at every invocation of packer. The <random> value is re-used as much as possible when naming resources, so users can better identify and group these transient resources when seen in their subscription.

The VHD is created on a user specified storage account, not a random one created at runtime. When a virtual machine is captured the resulting VHD is stored on the same storage account as the source VHD. The VHD created by Packer must persist after a build is complete, which is why the storage account is set by the user.

The basic steps for a build are:

  1. Create a resource group.
  2. Validate and deploy a VM template.
  3. Execute provision - defined by the user; typically shell commands.
  4. Power off and capture the VM.
  5. Delete the resource group.
  6. Delete the temporary VM's OS disk.

The templates used for a build are currently fixed in the code. There is a template for Linux, Windows, and KeyVault. The templates are themselves templated with place holders for names, passwords, SSH keys, certificates, etc.

What's Randomized?

The Azure builder creates the following random values at runtime.

  • 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.
  • NIC Name: a random 15-character name prefixed with pkrni.
  • Public IP Name: a random 15-character name prefixed with pkrip.
  • OS Disk Name: a random 15-character name prefixed with pkros.
  • Data Disk Name: a random 15-character name prefixed with pkrdd.
  • Resource Group Name: a random 33-character name prefixed with packer-Resource-Group-.
  • Subnet Name: a random 15-character name prefixed with pkrsn.
  • SSH Key Pair: a 2,048-bit asymmetric key pair; can be overridden by the user.
  • Virtual Network Name: a random 15-character name prefixed with pkrvn.

The default alphabet used for random values is 0123456789bcdfghjklmnpqrstvwxyz. The alphabet was reduced (no vowels) to prevent running afoul of Azure decency controls.

The password alphabet used for random values is 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.

Windows

The Windows implementation is very similar to the Linux build, with the exception that it deploys a template to configure KeyVault. Packer communicates with a Windows VM using the WinRM protocol. Windows VMs on Azure default to using both password and certificate based authentication for WinRM. The password is easily set via the VM ARM template, but the certificate requires an intermediary. The intermediary for Azure is KeyVault. The certificate is uploaded to a new KeyVault provisioned in the same resource group as the VM. When the Windows VM is deployed, it links to the certificate in KeyVault, and Azure will ensure the certificate is injected as part of deployment.

The basic steps for a Windows build are:

  1. Create a resource group.
  2. Validate and deploy a KeyVault template.
  3. Validate and deploy a VM template.
  4. Execute provision - defined by the user; typically shell commands.
  5. Power off and capture the VM.
  6. Delete the resource group.
  7. Delete the temporary VM's OS disk.

A Windows build requires two templates and two deployments. Unfortunately, the KeyVault and VM cannot be deployed at the same time hence the need for two templates and deployments. The time required to deploy a KeyVault template is minimal, so overall impact is small.

See the example folder in the Packer project for more examples.