Deploying with Bare Metal service

This guide explains how to use Ironic to deploy nodes without any front-end service, such as OpenStack Compute (nova) or Metal3.


To simplify this task you can use the metalsmith tool which provides a convenient CLI for the most common cases.


Allocation is a way to find and reserve a node suitable for deployment. When an allocation is created, the list of available nodes is searched for a node with the given resource class and traits, similarly to how it is done in OpenStack Compute flavors. Only the resource class is mandatory, for example:

$ baremetal allocation create --resource-class baremetal --wait
| Field           | Value                                |
| candidate_nodes | []                                   |
| created_at      | 2019-04-03T12:18:26+00:00            |
| extra           | {}                                   |
| last_error      | None                                 |
| name            | None                                 |
| node_uuid       | 5d946337-b1d9-4b06-8eda-4fb77e994a0d |
| resource_class  | baremetal                            |
| state           | active                               |
| traits          | []                                   |
| updated_at      | 2019-04-03T12:18:26+00:00            |
| uuid            | e84f5d60-84f1-4701-a635-10ff90e2f3b0 |


The allocation processing is fast but nonetheless asynchronous. Use the --wait argument to wait for the results.

If an allocation is successful, it sets the node’s instance_uuid to the allocation UUID. The node’s UUID can be retrieved from the allocation’s node_uuid field.

An allocation is automatically deleted when the associated node is unprovisioned. If you don’t provision the node, you’re responsible for deleting the allocation.

See the allocation API reference for more information on how to use allocations.

Populating instance information

The node’s instance_info field is a JSON object that contains all information required for deploying an instance on bare metal. It has to be populated before deployment and is automatically cleared on tear down.

Image information

You need to specify image information in the node’s instance_info (see Creating instance images):

  • image_source - URL of the whole disk or root partition image, mandatory. The following schemes are supported: http://, https:// and file://. Files have to be accessible by the conductor. If the scheme is missing, an Image Service (glance) image UUID is assumed.

  • root_gb - size of the root partition, required for partition images.


    Older versions of the Bare Metal service used to require a positive integer for root_gb even for whole-disk images. You may want to set it for compatibility.

  • image_checksum - MD5 checksum of the image specified by image_source, only required for http:// images when using Direct deploy.

    Other checksum algorithms are supported via the image_os_hash_algo and image_os_hash_value fields. They may be used instead of the image_checksum field.


    If your operating system is running in FIPS 140-2 mode, MD5 will not be available, and you must use SHA256 or another modern algorithm.

    Starting with the Stein release of ironic-python-agent can also be a URL to a checksums file, e.g. one generated with:

    $ cd /path/to/http/root
    $ md5sum *.img > checksums
  • kernel, ramdisk - HTTP(s) or file URLs of the kernel and initramfs of the target OS. Must be added only for partition images. Supports the same schemes as image_source.

An example for a partition image:

baremetal node set $NODE_UUID \
    --instance-info image_source=http://image.server/my-image.qcow2 \
    --instance-info image_checksum=1f9c0e1bad977a954ba40928c1e11f33 \
    --instance-info kernel=http://image.server/my-image.kernel \
    --instance-info ramdisk=http://image.server/my-image.initramfs \
    --instance-info root_gb=10

With a SHA256 hash:

baremetal node set $NODE_UUID \
    --instance-info image_source=http://image.server/my-image.qcow2 \
    --instance-info image_os_hash_algo=sha256 \
    --instance-info image_os_hash_value=a64dd95e0c48e61ed741ff026d8c89ca38a51f3799955097c5123b1705ef13d4 \
    --instance-info kernel=http://image.server/my-image.kernel \
    --instance-info ramdisk=http://image.server/my-image.initramfs \
    --instance-info root_gb=10

With a whole disk image and a checksum URL:

baremetal node set $NODE_UUID \
    --instance-info image_source=http://image.server/my-image.qcow2 \
    --instance-info image_checksum=http://image.server/my-image.qcow2.CHECKSUM


Certain hardware types and interfaces may require additional or different fields to be provided. See specific guides under Drivers, Hardware Types and Hardware Interfaces.

When using low RAM nodes with http:// images that are not in the RAW format, you may want them cached locally, converted to raw and served from the conductor’s HTTP server:

baremetal node set $NODE_UUID --instance-info image_download_source=local

For software RAID with whole-disk images, the root UUID of the root partition has to be provided so that the bootloader can be correctly installed:

baremetal node set $NODE_UUID --instance-info image_rootfs_uuid=<uuid>


  • Boot mode can be specified per instance:

    baremetal node set $NODE_UUID \
        --instance-info capabilities='{"boot_mode": "uefi"}'

    Otherwise, the boot_mode capability from the node’s properties will be used.


    The two settings must not contradict each other.


    This capability was introduced in the Wallaby release series, previously ironic used a separate instance_info/deploy_boot_mode field instead.

  • To override the boot option used for this instance, set the boot_option capability:

    baremetal node set $NODE_UUID \
        --instance-info capabilities='{"boot_option": "local"}'
  • Starting with the Ussuri release, you can set root device hints per instance:

    baremetal node set $NODE_UUID \
        --instance-info root_device='{"wwn": "0x4000cca77fc4dba1"}'

    This setting overrides any previous setting in properties and will be removed on undeployment.

Overriding a hardware interface

Non-admins with temporary access to a node, may wish to specify different node interfaces. However, allowing them to set these interface values directly on the node is problematic, as there is no automated way to ensure that the original interface values are restored.

In order to temporarily override a hardware interface, simply set the appropriate value in instance_info. For example, if you’d like to override a node’s storage interface, run the following:

baremetal node set $NODE_UUID --instance-info storage_interface=cinder

instance_info values persist until after a node is cleaned.


This feature is available starting with the Wallaby release.

Attaching virtual interfaces

If using the OpenStack Networking service (neutron), you can attach its ports to a node before deployment as VIFs:

baremetal node vif attach $NODE_UUID $PORT_UUID


These are neutron ports, not ironic ports!

VIFs are automatically detached on deprovisioning.


  1. Validate that all parameters are correct:

    $ baremetal node validate $NODE_UUID
    | Interface  | Result | Reason                                                         |
    | boot       | True   |                                                                |
    | console    | False  | Missing 'ipmi_terminal_port' parameter in node's driver_info.  |
    | deploy     | True   |                                                                |
    | inspect    | True   |                                                                |
    | management | True   |                                                                |
    | network    | True   |                                                                |
    | power      | True   |                                                                |
    | raid       | True   |                                                                |
    | storage    | True   |                                                                |
  2. Now you can start the deployment, run:

    baremetal node deploy $NODE_UUID
  3. Starting with the Wallaby release you can also request custom deploy steps, see Requesting steps for details.

Deploying with a config drive

The configuration drive is a small image used to store instance-specific metadata and is present to the instance as a disk partition labeled config-2. See Enabling the configuration drive (configdrive) for a detailed explanation.

A configuration drive can be provided either as a whole ISO 9660 image or as JSON input for building an image. A first-boot service, such as cloud-init, must be running on the instance image for the configuration to be applied.

Building a config drive on the client side

For the format of the configuration drive, Bare Metal service expects a gzipped and base64 encoded ISO 9660 file with a config-2 label. The baremetal client can generate a configuration drive in the expected format. Pass a directory path containing the files that will be injected into it via the --config-drive parameter of the baremetal node deploy command, for example:

baremetal node deploy $NODE_UUID --config-drive /dir/configdrive_files


A configuration drive could also be a data block with a VFAT filesystem on it instead of ISO 9660. But it’s unlikely that it would be needed since ISO 9660 is widely supported across operating systems.

Building a config drive on the conductor side

Starting with the Stein release and ironicclient 2.7.0, you can request building a configdrive on the server side by providing a JSON with keys meta_data, user_data and network_data (all optional), e.g.:

baremetal node deploy $node_identifier \
    --config-drive '{"meta_data": {"hostname": "server1.cluster"}}'


When this feature is used, host name defaults to the node’s name or UUID.

SSH public keys can be provided as a mapping:

baremetal node deploy $NODE_UUID \
    --config-drive '{"meta_data": {"public_keys": {"0": "ssh key contents"}}}'

If using cloud-init, its configuration can be supplied as user_data, e.g.:

baremetal node deploy $NODE_UUID \
    --config-drive '{"user_data": "#cloud-config\n{\"users\": [{\"name\": ...}]}"}'


User data is a string, not a JSON! Also note that a prefix, such as #cloud-config, is required, see user data format.

Some first-boot services support network configuration in the OpenStack network data format. It can be provided in the network_data field of the configuration drive.

Ramdisk booting

Advanced operators, specifically ones working with ephemeral workloads, may find it more useful to explicitly treat a node as one that would always boot from a Ramdisk. See Booting a Ramdisk or an ISO for details.