Bifrost Guide

Bifrost Guide

From the bifrost developer documentation:

Bifrost (pronounced bye-frost) is a set of Ansible playbooks that automates the task of deploying a base image onto a set of known hardware using Ironic. It provides modular utility for one-off operating system deployment with as few operational requirements as reasonably possible.

Kolla uses bifrost as a mechanism for bootstrapping an OpenStack control plane on a set of baremetal servers. Kolla provides a container image for bifrost. Kolla-ansible provides a playbook to configure and deploy the bifrost container, as well as building a base OS image and provisioning it onto the baremetal nodes.

Hosts in the System

In a system deployed by bifrost we define a number of classes of hosts.

Control host
The control host is the host on which kolla and kolla-ansible will be installed, and is typically where the cloud will be managed from.
Deployment host
The deployment host runs the bifrost deploy container and is used to provision the cloud hosts.
Cloud hosts
The cloud hosts run the OpenStack control plane, compute and storage services.
Bare metal compute hosts:
In a cloud providing bare metal compute services to tenants via Ironic, these hosts will run the bare metal tenant workloads. In a cloud with only virtualised compute this category of hosts does not exist.


In many cases the control and deployment host will be the same, although this is not mandatory.


Bifrost supports provisioning of bare metal nodes. While kolla-ansible is agnostic to whether the host OS runs on bare metal or is virtualised, in a virtual environment the provisioning of VMs for cloud hosts and their base OS images is currently out of scope.

Cloud Deployment Procedure

Cloud deployment using kolla and bifrost follows the following high level steps:

  1. Install and configure kolla and kolla-ansible on the control host.
  2. Deploy bifrost on the deployment host.
  3. Use bifrost to build a base OS image and provision cloud hosts with this image.
  4. Deploy OpenStack services on the cloud hosts provisioned by bifrost.


Prepare the Control Host

Follow the Install dependencies section of the Quick Start guide instructions to set up kolla and kolla-ansible dependencies. Follow the instructions in either the Install kolla for development section or the Install kolla for deployment or evaluation section to install kolla and kolla-ansible.

Prepare the Deployment Host

RabbitMQ requires that the system’s hostname resolves to the IP address that it has been configured to use, which with bifrost will be Bifrost will attempt to modify /etc/hosts on the deployment host to ensure that this is the case. Docker bind mounts /etc/hosts into the container from a volume. This prevents atomic renames which will prevent Ansible from fixing the /etc/hosts file automatically.

To enable bifrost to be bootstrapped correctly add an entry to /etc/hosts resolving the deployment host’s hostname to, for example:

ubuntu@bifrost:/repo/kolla$ cat /etc/hosts bifrost localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts bifrost

Build a Bifrost Container Image

This section provides instructions on how to build a container image for bifrost using kolla.

Enable Source Build Type

Currently kolla only supports the source install type for the bifrost image.

Configuration File

If required, generate a default configuration file for kolla-build:

cd kolla
tox -e genconfig

Modify kolla-build.conf, setting install_type to source:

install_type = source

Command line

Alternatively, instead of using kolla-build.conf, a source build can be enabled by appending --type source to the kolla-build or tools/ command.

Build Container


cd kolla
tools/ bifrost-deploy


kolla-build bifrost-deploy


By default kolla-build will build all containers using CentOS as the base image. To change this behavior, use the following parameter with kolla-build or tools/ command:

--base [ubuntu|centos|oraclelinux]

Configure and Deploy a Bifrost Container

This section provides instructions for how to configure and deploy a container running bifrost services.

Prepare Kolla-Ansible Inventory

Kolla-ansible will deploy bifrost on the hosts in the bifrost Ansible group. In the all-in-one and multinode inventory files, a bifrost group is defined which contains all hosts in the deployment group. This top level deployment group is intended to represent the host running the bifrost_deploy container. By default, this group contains localhost. See Multinode Deployment of Kolla for details on how to modify the Ansible inventory in a multinode deployment.

Bifrost does not currently support running on multiple hosts so the bifrost group should contain only a single host, however this is not enforced by kolla-ansible. Bifrost manages a number of services that conflict with services deployed by kolla including OpenStack Ironic, MariaDB, RabbitMQ and (optionally) OpenStack Keystone. These services should not be deployed on the host on which bifrost is deployed.

Prepare Kolla-Ansible Configuration

Follow the instructions in Quick Start to prepare kolla-ansible’s global configuration file globals.yml. For bifrost, the bifrost_network_interface variable should be set to the name of the interface that will be used to provision bare metal cloud hosts if this is different than network_interface. For example to use eth1:

bifrost_network_interface: eth1

Note that this interface should typically have L2 network connectivity with the bare metal cloud hosts in order to provide DHCP leases with PXE boot options.

Since bifrost only supports the source image type, ensure that this is reflected in globals.yml

kolla_install_type: source

Prepare Bifrost Configuration

Kolla ansible custom configuration files can be placed in a directory given by the node_custom_config variable, which defaults do /etc/kolla/config. Bifrost configuration files should be placed in this directory or in a bifrost subdirectory of it (e.g. /etc/kolla/config/bifrost). Within these directories the files bifrost.yml, servers.yml and dib.yml can be used to configure Bifrost.

Create a Bifrost Inventory

The file servers.yml defines the bifrost hardware inventory that will be used to populate Ironic. See the bifrost dynamic inventory examples for further details.

For example, the following inventory defines a single node managed via the Ironic agent_ipmitool driver. The inventory contains credentials required to access the node’s BMC via IPMI, the MAC addresses of the node’s NICs, an IP address to configure the node’s configdrive with, a set of scheduling properties and a logical name.

  uuid: "31303735-3934-4247-3830-333132535336"
      ipmi_username: "admin"
      ipmi_address: ""
      ipmi_password: "root"
      mac: "1c:c1:de:1c:aa:53"
      mac: "1c:c1:de:1c:aa:52"
  driver: "agent_ipmitool"
  ipv4_address: ""
    cpu_arch: "x86_64"
    ram: "24576"
    disk_size: "120"
    cpus: "16"
  name: "cloud1"

The required inventory will be specific to the hardware and environment in use.

Create Bifrost Configuration

The file bifrost.yml provides global configuration for the bifrost playbooks. By default kolla mostly uses bifrost’s default variable values. For details on bifrost’s variables see the bifrost documentation.

For example:

mysql_service_name: mysql
ansible_python_interpreter: /var/lib/kolla/venv/bin/python
enabled_drivers: agent_ipmitool,agent_ipminative
# uncomment below if needed
# dhcp_pool_start:
# dhcp_pool_end:
# dhcp_lease_time: 12h
# dhcp_static_mask:

Create Disk Image Builder Configuration

The file dib.yml provides configuration for bifrost’s image build playbooks. By default kolla mostly uses bifrost’s default variable values when building the baremetal OS and deployment images, and will build an Ubuntu-based image for deployment to nodes. For details on bifrost’s variables see the bifrost documentation.

For example to use the debian Disk Image Builder OS element:

dib_os_element: debian

See the diskimage-builder documentation for more details.

Deploy Bifrost

The bifrost container can be deployed either using kolla-ansible or manually.


cd kolla-ansible
tools/kolla-ansible deploy-bifrost
kolla-ansible deploy-bifrost


Start Bifrost Container
docker run -it --net=host -v /dev:/dev -d \
--privileged --name bifrost_deploy \
Copy Configuration Files
docker exec -it bifrost_deploy mkdir /etc/bifrost
docker cp /etc/kolla/config/bifrost/servers.yml bifrost_deploy:/etc/bifrost/servers.yml
docker cp /etc/kolla/config/bifrost/bifrost.yml bifrost_deploy:/etc/bifrost/bifrost.yml
docker cp /etc/kolla/config/bifrost/dib.yml bifrost_deploy:/etc/bifrost/dib.yml
Bootstrap Bifrost
docker exec -it bifrost_deploy bash
Generate an SSH Key
Bootstrap and Start Services
cd /bifrost
. env-vars
cat > /etc/rabbitmq/rabbitmq-env.conf << EOF
ansible-playbook -vvvv \
-i /bifrost/playbooks/inventory/target \
/bifrost/playbooks/install.yaml \
-e @/etc/bifrost/bifrost.yml \
-e @/etc/bifrost/dib.yml \
-e skip_package_install=true

Validate the Deployed Container

docker exec -it bifrost_deploy bash
cd /bifrost
. env-vars

Running “ironic node-list” should return with no nodes, for example

(bifrost-deploy)[root@bifrost bifrost]# ironic node-list
| UUID | Name | Instance UUID | Power State | Provisioning State | Maintenance |

Enroll and Deploy Physical Nodes

Once we have deployed a bifrost container we can use it to provision the bare metal cloud hosts specified in the inventory file. Again, this can be done either using kolla-ansible or manually.



tools/kolla-ansible deploy-servers


kolla-ansible deploy-servers


docker exec -it bifrost_deploy bash
cd /bifrost
. env-vars
export BIFROST_INVENTORY_SOURCE=/etc/bifrost/servers.yml
ansible-playbook -vvvv \
-i /bifrost/playbooks/inventory/ \
/bifrost/playbooks/enroll-dynamic.yaml \
-e "ansible_python_interpreter=/var/lib/kolla/venv/bin/python" \
-e @/etc/bifrost/bifrost.yml

docker exec -it bifrost_deploy bash
cd /bifrost
. env-vars
export BIFROST_INVENTORY_SOURCE=/etc/bifrost/servers.yml
ansible-playbook -vvvv \
-i /bifrost/playbooks/inventory/ \
/bifrost/playbooks/deploy-dynamic.yaml \
-e "ansible_python_interpreter=/var/lib/kolla/venv/bin/python" \
-e @/etc/bifrost/bifrost.yml

At this point Ironic should clean down the nodes and install the default OS image.

Advanced Configuration

Bring Your Own Image


Bring Your Own SSH Key

To use your own SSH key after you have generated the passwords.yml file update the private and public keys under bifrost_ssh_key.

Known issues

SSH daemon not running

By default sshd is installed in the image but may not be enabled. If you encounter this issue you will have to access the server physically in recovery mode to enable the sshd service. If your hardware supports it, this can be done remotely with ipmitool and Serial Over LAN. For example

ipmitool -I lanplus -H -U admin -P root sol activate
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