add iscsi support to the oci image type

[ondrejbudai]

Bare metal instances can access block volumes only using iSCSI. Therefore, we need to install iscsi-initiator-utils and pass the right kernel options in order to make boot from iSCSI-attached volume possible.

This pull request includes:

• adequate testing for the new functionality or fixed issue
• adequate documentation informing people about the change such as
  • submit a PR for the guides repository if this PR changed any behavior described there: https://www.osbuild.org/guides/

[teg]

For the final version, I think this should be part of the Platform abstraction.

[schutzbot]

⚠️ This PR introduces changes in at least one manifest (when comparing PR HEAD 29db29f with the main merge-base 3cdfa9d). Please review the changes. The changes can be found in the artifacts of the Manifest-diff job [0] as manifests.diff.

[0] https://gitlab.com/redhat/services/products/image-builder/ci/osbuild-composer/-/jobs/3735671519/artifacts/browse

[ondrejbudai]

We don't have enough resources to get this finished anytime soon. Also, everything in this PR can be achieved just by applying the right customizations. Here's a quick guide I put together:

1. Install image builder (needs a subscribed machine):

dnf install -y osbuild-composer composer-cli

2. Enable the image building service

systemctl enable --now osbuild-composer.socket

3. Create a file named blueprint.toml with the following content:

name = "oci-baremetal"

[[packages]]
name = "iscsi-initiator-utils"

[customizations.kernel]
append = "rd.iscsi.ibft=1 rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=6000"

4. Push the blueprint file into image builder

sudo composer-cli blueprints push blueprint.toml

5. Start an image build

sudo composer-cli compose start oci-baremetal qcow2

6. Wait for it to be FINISHED

sudo composer-cli compose list

7. Download the image

sudo composer-cli compose image <UUID OF THE COMPOSE>