Demo: Disk partitioning with bootc-image-builder

2024-10-07

We're working on adding advanced partitioning customizations to bootc-image-builder. This demo is a preview of the new features.

NOTES:

• The customization format has not been finalised. The exact names and structure of the configuration may change, but the functionality shown will be supported.
• We have plans to include partitioning configurations in the base image that bootc-image-builder will read to create the partitioning layout, making the container itself the source of truth for the partition table as well.
• Mountpoints for partitions and logical volumes should be created in the base container image used to build the disk. This is particularly important for top-level mountpoints, such as the /app mountpoint we will use in this demo. In the final version of this feature, bootc-image-builder will validate the configuration against the bootc container before building, in order to avoid creating unbootable images.

Part 0: bootc-image-builder

Since this is a preview, I'll be using a bootc-image-builder image that I built myself to include the new features:

quay.io/achilleas/bootc-image-builder:demo

This feature should be available in the upstream (centos-bootc) image soon.

To build the image, I'll be using a container derived from quay.io/centos-bootc/centos-bootc:stream9. This image is created using the Containerfile in this repository and is currently available at quay.io/achilleas/centos-bootc:stream9-app.

Part 1: Plain partitioning

Source: 01-plain

Plain partitioning (i.e. non-LVM) example. Adds a data partition, mounted at /var/data, an app partition mounted at /app, and sets the size for the root partition to 3 GiB.

Part 2: LVM partitioning

Source 02-lvm

LVM partitioning example. Creates a 10 GiB Volume Group named centosvg and creates three Logical Volumes, one for root, one for /var/data, and another for /app.