Hands-on lab for using osbuild and ostree native containers
In this repo, you'll find instructions for using osbuild to generate a Fedora IoT artifact, creating a new base container image from the ostree commit, and creating customized container images to rebase your Fedora IoT system to.
- Fedora virtual machine(s)
- Quay.io account
- General understanding of osbuild
- General understanding of containers
You'll need one or more Fedora virtual machines: one system for installing osbuild and building artifacts. Another system for installing Fedora IoT; this could be another VM or a separate physical device. (Your osbuild system could also be a physical system, but it assumed most folks will be using a VM)
NOTE: your osbuild system should have at least 20G of unused, available disk space in order to successfully build this lab.
We'll refer to the system where osbuild runs as the "builder" system and the system where Fedora IoT will be installed as your "destination" system.
On your "builder" system, follow the instructions for installing osbuild and osbuild-composer.
sudo dnf install osbuild-composer composer-cli
sudo systemctl enable --now osbuild-composer.socket
sudo usermod -a -G weldr <user>
newgrp weldrOn your "builder" system, create an empty blueprint that can be used to create an ostree commit.
Your empty TOML file should look something like this:
name = "minimal"
description = "minimal fedora iot blueprint"
version = "1.0.0"
modules = []
groups = []
distro = "fedora-38"Push the blueprint with composer-cli:
composer-cli blueprints push minimal.toml
Start the build process for the ostree commit; we're choosing the iot-commit artifact because we want to be able to easily access the resulting ostree repo on-disk and via HTTP:
composer-cli compose start-ostree minimal iot-commit
Wait the necessary time for the build to complete; time will vary based on the specs of your "builder" system.
When the build has completed, fetch the tarball, explode it to disk, and serve it up via HTTP. This might be best done in a separate terminal so as not to flood your working terminal with log messages.
composer-cli compose image <uuid>
tar -xf <uuid>.tar
cd repo
python3 -m http.serverHINT: the commit.tar artifact should look simiar to this:
$ ls -lh 64cd0719-fd07-4b32-a116-0192cecdada3-commit.tar
-rw-------. 1 core weldr 785M Jul 27 15:36 64cd0719-fd07-4b32-a116-0192cecdada3-commit.tarNote the location of the repo directory on the disk, you will need this location when encapsulating the ostree commit into a container image.
Create a blueprint that you can use to create an installer artifact. You should include some basic user customizations so that you can login to your Fedora IoT system later.
name = "iso"
description = "blueprint to create iot-installer"
version = "1.0.0"
distro = "fedora-38"
[[customizations.user]]
name = "core"
key = "ssh-rsa ...."
password = "..."
groups = ["wheel"]And push the blueprint with composer-cli
composer-cli blueprints push iso.toml
Start the build process for the installer artifact; the ostree repo should be served via HTTP on port 8080 from the previous steps.
composer-cli compose start-ostree --url http://localhost:8000/ iso iot-installer
Wait for the build to complete and then fetch the ISO to be used for installation:
composer-cli compose image <uuid>
Using the ISO you created in the previous steps, install Fedora IoT in a VM or on your "destination" system.
The Anaconda installer should walk you through the necessary steps; they will not be covered as part of this lab.
Ensure that you are able to boot your "destination" system into Fedora IoT and successfully SSH to the IoT system.
On your "builder" system, create a new base image from the ostree commit using the rpm-ostree command.
rpm-ostree compose container-encapsulate --repo=</path/to/ostree/repo> fedora/38/x86_64/iot containers-storage:quay.io/<username>/fedora-iot-base:38
Optionally tag your image as :latest and push the image reference(s) to the registry; the podman login command can be retrieved from the settings page of your Quay.io account.
podman login -u="<username>" -p="<password>" quay.io
podman tag quay.io/<username>/fedora-iot-base:38 quay.io/<username>/fedora-iot-base:latest
podman push quay.io/<username>/fedora-iot-base:38
podman push quay.io/<username>/fedora-iot-base:latestYou should go to the settings page for your new container image on Quay.io and mark the repository as public.
Create a Containerfile that starts with your new base image and use rpm-ostree install to install a new package. An example is provided below:
FROM quay.io/<username>/fedora-iot-base:38
RUN rpm-ostree install strace && \
ostree container commitNOTE: it is recommended (required?) to use ostree container commit as your final step, as it performs finalization steps that are needed for ostree systems. (For more information, see ostreedev/ostree-rs-ext#159)
You could create this Containerfile on your "builder" system or any other system where podman is installed.
With the Containerfile, you can now build and push a new container image.
podman build -t quay.io/<username>/fedora-iot-custom:latest -f Containerfile .
podman push quay.io/<username>/fedora-iot-custom:latestYou'll need to go to the settings page on Quay.io for the custom image you just pushed and mark the repository as public.
On your "destination" system where Fedora IoT has been installed, rebase the system to your new customized image.
sudo rpm-ostree rebase --experimental ostree-unverified-registry:quay.io/<username>/fedora-iot-custom:latest
When you reboot your "destination" system, you should be in a new deployment and the package that you had installed in your Containerfile should be available.
Let's enable automatic updates driven by rpm-ostree and watch what happens when we update the container image on the registry.
On your "destination" system, configure the automatic update mechanism of rpm-ostree to stage the updates. This allows the user to have control when they want to have the updates applied.
sudo sed -i '/AutomaticUpdatePolicy=none/c\AutomaticUpdatePolicy=stage' /etc/rpm-ostreed.conf
sudo rpm-ostree reloadAnd adjust the timer for the updates to happen every minute so we don't have to wait around for the timer to fire. Create a drop-in file to override the timer settings and then reload systemd:
sudo mkdir -p /etc/systemd/system/rpm-ostreed-automatic.timer.d/
sudo tee /etc/systemd/system/rpm-ostreed-automatic.timer.d/override.conf > /dev/null << EOF
[Timer]
OnActiveSec=60
EOF
sudo systemctl daemon-reload
sudo systemctl enable rpm-ostreed-automatic.timer --nowWe can embed configuration files (or any files really) as part of the customized container image. This streamlines the process of doing OS updates and configuration changes via the same mechanism.
In this example, we are adding a dnf repo to the system. Create the /etc directory structure and add in a .repo file.
mkdir -p etc/yum.repos.d/
pushd etc/yum.repos.d/
curl -LO https://copr.fedorainfracloud.org/coprs/g/redhat-et/microshift/repo/fedora-38/group_redhat-et-microshift-fedora-38.repo
popdCreate a new Containerfile to copy in the .repo file.
FROM quay.io/<username>/fedora-iot-custom:latest
COPY etc /etcYour directory structure should look like this:
tree .
.
├── Containerfile.update
└── etc
└── yum.repos.d
└── group_redhat-et-microshift-fedora-38.repo
3 directories, 2 filesNow build and push the updated image; we'll use the same :latest tag so that the automatic update mechanism picks up the new container image.
podman build -t quay.io/<username>/fedora-iot-custom:latest -f Containerfile.update .
podman push quay.io/<username>/fedora-iot-custom:latestOn the destination Fedora IoT system, you should be able to see the updated container image being fetched by the automatic update mechanism. Or the update has already been fetched and staged.
rpm-ostree status