Create MachineConfigs to Configure RHCOS


"Butane (formerly the Fedora CoreOS Config Transpiler) is a tool that consumes a Butane Config and produces an Ignition Config, which is a JSON document that can be given to a Fedora CoreOS machine when it first boots." [1]

Butane is available in a container image, we can pull the latest version locally like so:

# Pull the latest release
podman pull

# Run butane using standard in and standard out
podman run -i --rm --pretty --strict < your_config.bu > transpiled_config.ign

# Run butane using files.
podman run --rm -v /path/to/your_config.bu:/config.bu:z --pretty --strict /config.bu > transpiled_config.ign

We can create a CLI alias to make running the Butane container much easier like so:

alias butane='podman run --rm --tty --interactive \
              --security-opt label=disable        \
              --volume ${PWD}:/pwd --workdir /pwd \

For more detailed information on how to structure your Butane file see [1]. Once created you can convert the butane config to an igntion file like so:

butane master_chrony_machineconfig.bu -o master_chrony_machineconfig.yaml
butane worker_chrony_machineconfig.bu -o worker_chrony_machineconfig.yaml