Populating instance_info

Image information

You need to specify image information in the node’s instance_info (see Create user images for the Bare Metal service):

  • image_source - URL of the whole disk or root partition image, mandatory.

  • 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.


    Additional checksum support exists 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.

For example:

baremetal node set $NODE_UUID \
    --instance-info image_source=$IMG \
    --instance-info image_checksum=$MD5HASH \
    --instance-info kernel=$KERNEL \
    --instance-info ramdisk=$RAMDISK \
    --instance-info root_gb=10

With a SHA256 hash:

baremetal node set $NODE_UUID \
    --instance-info image_source=$IMG \
    --instance-info image_os_hash_algo=sha256 \
    --instance-info image_os_hash_value=$SHA256HASH \
    --instance-info kernel=$KERNEL \
    --instance-info ramdisk=$RAMDISK \
    --instance-info root_gb=10

With a whole disk image:

baremetal node set $NODE_UUID \
    --instance-info image_source=$IMG \
    --instance-info image_checksum=$MD5HASH


For iLO drivers, fields that should be provided are:

  • ilo_deploy_iso under driver_info;

  • ilo_boot_iso, image_source, root_gb under instance_info.

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.


  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. You can provide a configdrive as a JSON or as an ISO image, e.g.:

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

    See Enabling the configuration drive (configdrive) for details.

  4. Starting with the Wallaby release you can also request custom deploy steps, see Requesting steps for details.

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.