ubuntu-image is a tool used for generating bootable images. You can use it to build Ubuntu images such as:

• Snap-based Ubuntu Core images from model assertions

• Classical preinstalled Ubuntu images using image definitions

The future versions of this tool will be more generalized, allowing users to build a wider range of Ubuntu images, including ISO/installer.

• Ubuntu 20.04 (Focal Fossa) or newer (recommended: Ubuntu 24.04 (Noble Numbat))

• Ability to install snaps (SnapStore: ubuntu-image)

See Build your first Ubuntu Core image for instructions on how to use ubuntu-image to build an Ubuntu core image on a Raspberry Pi.

ubuntu-image offers two basic sub-commands for building snap-based and classical images.

To build a snap-based image with ubuntu-image, you need a model assertion. A model assertion is a YAML file that describes a particular combination of core, kernel, and gadget snaps, along with other declarations, signed with a digital signature asserting its authenticity. The ubuntu-image command only requires the path to this model assertion to build snap-based images.

To build snap-based images with ubuntu-image, use the following command:

ubuntu-image snap model.assertion

See Build your first Ubuntu Core image for more information on building snap-based images using ubuntu-image. To build an image with custom snaps, see Build an image with custom snaps.

Classical images are built from image definitions, which are YAML files. The image definition YAML file specifies the various configurations required to build a classical image, including the path to the gadget.yaml file. See Image Definition for the detailed specification of what is supported in the image definition YAML file.

To build classical images with ubuntu-image, use the following command:

ubuntu-image classic image_definition.yaml

See Contributing to ubuntu-image for instructions on how to set up, build, and test ubuntu-image in development mode.

The ubuntu-image project is licensed under GNU General Public License v3.0.

To learn how to contribute to the ubuntu-image project, see Contributing to ubuntu-image.

• Project home: https://github.com/Canonical/ubuntu-image
• Report bugs at: https://bugs.launchpad.net/ubuntu-image
• Git clone: https://github.com/Canonical/ubuntu-image.git
• Reference page: ubuntu-image syntax and options
• Building a gadget snap: Building a gadget snap
• Gadget tree: pc-gadget
• gadget.yaml specification: Gadget snaps