This section covers configuration of the Bifrost service that runs on the seed host. Bifrost configuration is typically applied in ${KAYOBE_CONFIG_PATH}/bifrost.yml. Consult the Bifrost documentation for further details of Bifrost usage and configuration.

Bifrost installation


This section may be skipped if using an upstream Bifrost container image.

The following options are used if building the Bifrost container image locally.


URL of Bifrost source code repository. Default is


Version (branch, tag, etc.) of Bifrost source code repository. Default is {{ openstack_branch }}, which is the same as the Kayobe upstream branch name.

For example, to install Bifrost from a custom git repository:

kolla_bifrost_source_version: downstream

Overcloud root disk image configuration


This configuration only applies when overcloud_dib_build_host_images (set in ${KAYOBE_CONFIG_PATH}/overcloud-dib.yml) is changed to false.

Bifrost uses Diskimage builder (DIB) to build a root disk image that is deployed to overcloud hosts when they are provisioned. The following options configure how this image is built. Consult the Diskimage-builder documentation for further information on building disk images.

The default configuration builds a whole disk (partitioned) image using the selected OS distribution with serial console enabled, and SELinux disabled if CentOS Stream is used. Rocky Linux 9 users should use the default method of building images with Diskimage builder directly.


DIB base OS element. Default is {{ os_distribution }}.


DIB image OS release. Default is {{ os_release }}.


Added in the Train release. Use kolla_bifrost_dib_elements in earlier releases.

List of default DIB elements. Default is ["disable-selinux", "enable-serial-console", "vm"] when os_distribution is centos or rocky, ["enable-serial-console", "vm"] otherwise. The vm element is poorly named, and causes DIB to build a whole disk image rather than a single partition.


Added in the Train release. Use kolla_bifrost_dib_elements in earlier releases.

List of additional DIB elements. Default is none.


List of DIB elements. Default is a combination of kolla_bifrost_dib_elements_default and kolla_bifrost_dib_elements_extra.


DIB init element. Default is cloud-init-datasources.


Added in the Train release. Use kolla_bifrost_dib_env_vars in earlier releases.

DIB default environment variables. Default is {DIB_BOOTLOADER_DEFAULT_CMDLINE: "nofb nomodeset gfxpayload=text net.ifnames=1", "DIB_CLOUD_INIT_DATASOURCES": "ConfigDrive"}.


Added in the Train release. Use kolla_bifrost_dib_env_vars in earlier releases.

DIB additional environment variables. Default is none.


DIB environment variables. Default is combination of kolla_bifrost_dib_env_vars_default and kolla_bifrost_dib_env_vars_extra.


List of DIB packages to install. Default is to install no extra packages.

The disk image is built during the deployment of seed services. It is worth noting that currently, the image will not be rebuilt if it already exists. To force rebuilding the image, it is necessary to remove the file. On the seed:

docker exec bifrost_deploy rm /httpboot/deployment_image.qcow2

Then on the control host:

(kayobe) $ kayobe seed service deploy

Example: Adding an element

In the following, we extend the list of DIB elements to add the growpart element:

  - "growpart"

Example: Building an XFS root filesystem image

By default, DIB will format the image as ext4. In some cases it might be useful to use XFS, for example when using the overlay Docker storage driver which can reach the maximum number of hardlinks allowed by ext4.

In DIB, we achieve this by setting the FS_TYPE environment variable to xfs.

  FS_TYPE: "xfs"

Example: Configuring a development user account


A development user account should not be used in production.

When debugging a failed deployment, it can sometimes be necessary to allow access to the image via a preconfigured user account with a known password. This can be achieved via the devuser element.

This example shows how to add the devuser element, and configure a username and password for an account that has passwordless sudo:

  - "devuser"

  DIB_DEV_USER_PASSWORD: "correct horse battery staple"

Alternatively, the dynamic-login element can be used to authorize SSH keys by appending them to the kernel arguments.

Example: Installing a package

It can be necessary to install additional packages in the root disk image. Rather than needing to write a custom DIB element, we can use the kolla_bifrost_dib_packages variable. For example, to install the biosdevname package:

  - "biosdevname"

Disk image deployment configuration

The name of the root disk image to deploy can be configured via the kolla_bifrost_deploy_image_filename option, which defaults to deployment_image.qcow2. It can be defined globally in ${KAYOBE_CONFIG_PATH}/bifrost.yml, or defined per-group or per-host in the Kayobe inventory. This can be used to provision different images across the overcloud.

While only a single disk image can be built with Bifrost, starting from the Yoga 12.0.0 release, Kayobe supports building multiple disk images directly through Diskimage builder. Consult the overcloud host disk image build documentation for more details.

Ironic configuration

The following options configure the Ironic service in the bifrost-deploy container.


List of hardware types to enable for Bifrost’s Ironic. Default is ["ipmi"].


List of extra kernel parameters for Bifrost’s Ironic PXE configuration. Default is none.

Ironic Inspector configuration

The following options configure the Ironic Inspector service in the bifrost-deploy container.


List of of inspector processing plugins. Default is {{ inspector_processing_hooks }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


Which MAC addresses to add as ports during introspection. One of all, active or pxe. Default is {{ inspector_add_ports }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


List of extra kernel parameters for the inspector default PXE configuration. Default is {{ inspector_extra_kernel_options }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml. When customising this variable, the default extra kernel parameters should be kept to retain full node inspection capabilities.


List of introspection rules for Bifrost’s Ironic Inspector service. Default is {{ inspector_rules }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


Ironic inspector IPMI username to set via an introspection rule. Default is {{ ipmi_username }}, defined in ${KAYOBE_CONFIG_PATH}/bmc.yml.


Ironic inspector IPMI password to set via an introspection rule. Default is {{ ipmi_password }}, defined in ${KAYOBE_CONFIG_PATH}/bmc.yml.


Ironic inspector network interface name on which to check for an LLDP switch port description to use as the node’s name. Default is {{ inspector_lldp_switch_port_interface_default }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


Ironic inspector deployment kernel location. Default is http://{{ provision_oc_net_name | net_ip }}:8080/ipa.kernel.


Ironic inspector deployment ramdisk location. Default is http://{{ provision_oc_net_name | net_ip }}:8080/ipa.initramfs.


Timeout of hardware inspection on overcloud nodes, in seconds. Default is {{ inspector_inspection_timeout }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.

Ironic Python Agent (IPA) configuration


If building IPA images locally (ipa_build_images is true) this section can be skipped.

The following options configure the source of Ironic Python Agent images used by Bifrost for inspection and deployment. Consult the Ironic Python Agent documentation for full details.


URL of Ironic Python Agent (IPA) kernel image. Default is {{ inspector_ipa_kernel_upstream_url }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


URL of checksum of Ironic Python Agent (IPA) kernel image. Default is {{ inspector_ipa_kernel_checksum_url }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


Algorithm of checksum of Ironic Python Agent (IPA) kernel image. Default is {{ inspector_ipa_kernel_checksum_algorithm }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


URL of Ironic Python Agent (IPA) ramdisk image. Default is {{ inspector_ipa_ramdisk_upstream_url }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


URL of checksum of Ironic Python Agent (IPA) ramdisk image. Default is {{ inspector_ipa_ramdisk_checksum_url }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.


Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image. Default is {{ inspector_ipa_ramdisk_checksum_algorithm }}, defined in ${KAYOBE_CONFIG_PATH}/inspector.yml.

Inventory configuration


This feature is currently not well tested. It is advisable to use autodiscovery of overcloud servers instead.

The following option is used to configure a static inventory of servers for Bifrost.


Server inventory for Bifrost in the JSON file format.

Custom Configuration

Further configuration of arbitrary Ansible variables for Bifrost can be provided via the following files:

  • ${KAYOBE_CONFIG_PATH}/kolla/config/bifrost/bifrost.yml

  • ${KAYOBE_CONFIG_PATH}/kolla/config/bifrost/dib.yml

These are both passed as extra variables files to ansible-playbook, but the naming scheme provides a separation of DIB image related variables from other variables. It may be necessary to inspect the Bifrost source code for the full set of variables that may be configured.

For example, to configure debug logging for Ironic Inspector:

inspector_debug: true