Configuration specifications

Ignition configurations must conform to a specific version of the configuration specification schema, specified with the ignition.version: X.Y.Z field in the configuration.

See the Upgrading Configs page for instructions to update a configuration to the latest specification.

Stable specification versions

We recommend that you always use the latest stable specification to benefit from new features and bug fixes. The following stable specification versions are currently supported in Ignition:

Experimental specification versions

Do not use the experimental specification for anything beyond development and testing as it is subject to change without warning or announcement. The following experimental specification version is currently available in Ignition:

Legacy spec 2.x configuration specifications

Documentation for the spec 1 and 2.x configuration specifications is available in the legacy spec2x branch of Ignition. Those specification versions are used by older versions of RHEL CoreOS and Flatcar Container Linux. This branch is no longer maintained.

Specification versions and Ignition releases

This table lists, for each stable specification version, the first released version of Ignition that supports it. To get all bug fixes, it is usually recommended to use the latest Ignition release.

Spec versionIgnition release