Image Builder supports building rpm-ostree system images with embedded container images. Embedded container images are immediately available to container engines like podman and cri-o after booting the system, without having to pull images over the network from a container registry. This means container workloads can start up without delay and without requiring network connectivity.
To embed a container image, add it to the Image Builder blueprint as follows:
[[containers]]
source = "<your_image_pullspec_with_tag_or_digest>"
To embed MicroShift container images, you need to know the exact list of container image references used by the MicroShift version you are deploying. You can obtain this list by installing the microshift-release-info RPM package of the same version, for example:
$ sudo dnf install -y microshift-release-info-4.12.0-1
$ ls /usr/share/microshift/release
release-aarch64.json release-x86_64.json
Alternatively, you can download and unpack the RPM package without installing it:
$ sudo dnf download microshift-release-info-4.12.0-1
microshift-release-info-4.12.0-1.el8.noarch.rpm
$ rpm2cpio microshift-release-info-4.12.0-1.el8.noarch.rpm | cpio -idmv
./usr/share/microshift/release/release-aarch64.json
./usr/share/microshift/release/release-x86_64.json
Using the release info for your CPU architecture, you can now generate the section to embed the container images to your blueprint.toml:
$ jq -r '.images | .[] | ("[[containers]]\nsource = \"" + . + "\"\n")' release-$(uname -i).json >> blueprint.tonl
Remember to pin the version of the MicroShift RPMs in the blueprint to the version matching your container images. The resulting blueprint.toml should look simiar to this:
name = "microshift-offline"
description = ""
version = "0.0.1"
modules = []
groups = []
[[packages]]
name = "microshift"
version = "4.12.0-1"
[[containers]]
source = "quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:9945c3f5475a37e145160d2fe6bb21948f1024a856827bc9e7d5bc882f44a750"
[[containers]]
source = "quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:82cfef91557f9a70cff5a90accba45841a37524e9b93f98a97b20f6b2b69e5db"
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