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Chapter 1. RHEL image builder description

To deploy a system, create a system image. To create RHEL system images, use the RHEL image builder tool. You can use RHEL image builder to create customized system images of RHEL, including system images prepared for deployment on cloud platforms. RHEL image builder automatically handles the setup details for each output type and is therefore easier to use and faster to work with than manual methods of image creation. You can access the RHEL image builder functionalities by using the command-line interface in the composer-cli tool, or the graphical user interface in the RHEL web console.

Note

From RHEL 8.3 onward, the osbuild-composer back end replaces lorax-composer. The new service provides REST APIs for image building.

1.1. RHEL image builder terminology

RHEL image builder uses the following concepts:

Blueprint

A blueprint is a description of a customized system image. It lists the packages and customizations that will be part of the system. You can edit blueprints with customizations and save them as a particular version. When you create a system image from a blueprint, the image is associated with the blueprint in the RHEL image builder interface.

Create blueprints in the TOML format.

Compose
Composes are individual builds of a system image, based on a specific version of a particular blueprint. Compose as a term refers to the system image, the logs from its creation, inputs, metadata, and the process itself.
Customizations
Customizations are specifications for the image that are not packages. This includes users, groups, and SSH keys.

1.2. RHEL image builder output formats

RHEL image builder can create images in multiple output formats shown in the following table.

Table 1.1. RHEL image builder output formats

DescriptionCLI nameFile extension

QEMU Image

qcow2

.qcow2

Disk Archive

tar

.tar

Amazon Web Services

raw

.raw

Microsoft Azure

vhd

.vhd

Google Cloud Platform

gce

.tar.gz

VMware vSphere

vmdk

.vmdk

VMware vSphere

ova

.ova

Openstack

openstack

.qcow2

RHEL for Edge Commit

edge-commit

.tar

RHEL for Edge Container

edge-container

.tar

RHEL for Edge Installer

edge-installer

.iso

RHEL for Edge Raw Image

edge-raw-image

.raw.xz

RHEL for Edge Simplified Installer

edge-simplified-installer

.iso

RHEL for Edge AMI

edge-ami

.ami

RHEL for Edge VMDK

edge-vsphere

.vmdk

RHEL Installer

image-installer

.iso

Oracle Cloud Infrastructure

.oci

.qcow2

To check the supported types, run the command:

# composer-cli compose types