Ignition is the utility used by CoreOS Linux to manipulate disks during the initramfs. This includes partitioning disks, formatting partitions, writing files (regular files, systemd units, networkd 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.
The documentation for Ignition can be found here.
Ignition is under very active development!
Please check out the roadmap for information about the timeline. Use the bug tracker to report bugs, but please avoid the urge to report lack of features for now.
The current scope of features can be found in the requirements documentation.