overcloud-dib.rst

Overcloud host disk image build

This section covers configuration for building overcloud host disk images with Diskimage builder (DIB), which is available from the Yoga 12.0.0 release. This configuration is applied in ${KAYOBE_CONFIG_PATH}/overcloud-dib.yml.

Enabling host disk image build

From the Yoga release, disk images for overcloud hosts can be built directly using Diskimage builder rather than through Bifrost. This is enabled with the following option:

overcloud_dib_build_host_images

Whether to build host disk images with DIB directly instead of through Bifrost. Setting it to true disables Bifrost image build and allows images to be built with the kayobe overcloud host image build command. Default value is false. This will change in a future release.

With this option enabled, Bifrost will be configured to stop building a root disk image. This will become the default behaviour in a future release.

Overcloud root disk image configuration

Kayobe uses Diskimage builder (DIB) to build root disk images that are deployed to overcloud hosts when they are provisioned. The following options configure how these images are built. Consult the :diskimage-builder-doc:`Diskimage-builder documentation <>` for further information on building disk images.

The default configuration builds a whole disk (partitioned) image using the selected :ref:`OS distribution <os-distribution>` (CentOS Stream 8 by default) with serial console enabled, and SELinux disabled if CentOS Stream is used. Cloud-init is used to process the configuration drive built by Bifrost during provisioning.

overcloud_dib_host_images

List of overcloud host disk images to build. Each element is a dict defining an image in a format accepted by the stackhpc.os-images role. Default is to build an image named deployment_image configured with the overcloud_dib_* variables defined below: {"name": "deployment_image", "elements": "{{ overcloud_dib_elements }}", "env": "{{ overcloud_dib_env_vars }}", "packages": "{{ overcloud_dib_packages }}"}.

overcloud_dib_os_element

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

overcloud_dib_os_release

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

overcloud_dib_elements_default

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

overcloud_dib_elements_extra

List of additional DIB elements. Default is none.

overcloud_dib_elements

List of DIB elements. Default is a combination of overcloud_dib_elements_default and overcloud_dib_elements_extra.

overcloud_dib_env_vars_default

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

overcloud_dib_env_vars_extra

DIB additional environment variables. Default is none.

overcloud_dib_env_vars

DIB environment variables. Default is combination of overcloud_dib_env_vars_default and overcloud_dib_env_vars_extra.

overcloud_dib_packages

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

overcloud_dib_git_elements_default

List of default git repositories containing Diskimage Builder (DIB) elements. See stackhpc.os-images role for usage. Default is empty.

overcloud_dib_git_elements_extra

List of additional git repositories containing Diskimage Builder (DIB) elements. See stackhpc.os-images role for usage. Default is empty.

overcloud_dib_git_elements

List of git repositories containing Diskimage Builder (DIB) elements. See stackhpc.os-images role for usage. Default is a combination of overcloud_dib_git_elements_default and overcloud_dib_git_elements_extra.

overcloud_dib_upper_constraints_file

Upper constraints file for installing packages in the virtual environment used for building overcloud host disk images. Default is {{ pip_upper_constraints_file }}.

Disk images are built with the following command:

(kayobe) $ kayobe overcloud host image build

It is worth noting that images will not be rebuilt if they already exist. To force rebuilding images, it is necessary to use the --force-rebuild argument.

(kayobe) $ kayobe overcloud host image build --force-rebuild

Example: Adding an element

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