Ignition is the utility used by Fedora CoreOS and RHEL CoreOS to manipulate disks during the initramfs. This includes partitioning disks, formatting partitions, writing files (regular files, systemd units, etc.), and configuring users. On first boot, Ignition reads its configuration from a source of truth (remote URL, network metadata service, hypervisor bridge, etc.) and applies the configuration.
Odds are good that you don't want to invoke Ignition directly. In fact, it isn't even present in the root filesystem. Take a look at the Getting Started Guide for details on providing Ignition with a runtime configuration.
- Mailing list: coreos@lists.fedoraproject.org
- IRC: #fedora-coreos on Libera.Chat
- Reporting bugs: issues
See CONTRIBUTING for details on submitting patches and the contribution workflow.
To help triage or fix bugs, see the current Ignition issues.
To validate a config for Ignition there are binaries for a cli tool called ignition-validate available on the releases page. There is also an ignition-validate container: quay.io/coreos/ignition-validate.
Example:
# This example uses podman, but docker can be used too
podman run --pull=always --rm -i quay.io/coreos/ignition-validate:release - < myconfig.ign
There are two branches:
main: the actively maintained version of Ignition, supporting config spec 3.x. Used by Fedora CoreOS and by Red Hat CoreOS starting with version 46.82.spec2x: the legacy branch of Ignition, supporting config spec 1 and 2.x. Used by older versions of RHEL CoreOS, alongside thespec2xbranch of ignition-dracut, and by Flatcar Container Linux. This branch is no longer maintained.
In Ignition 2.5.0, the old ignition-dracut repository, containing scripts and systemd units for boot-time execution, was merged into Ignition itself. CoreOS-specific Dracut modules have moved to the fedora-coreos-config repository.