jlebon/butane

Fedora CoreOS Config Transpiler

Fedora CoreOS Config Transpiler

The Fedora CoreOS Config Transpiler (FCCT) translates human readable Fedora CoreOS Configs (FCCs) into machine readable Ignition Configs. See the getting started guide for how to use FCCT and the configuration spec for everything FCCs support.

Project Layout

Each config spec is composed of a base and distro component. The base components roughly mirror the Ignition spec and are distro agnostic. The distro components contain sugar for common configuration of the host (e.g. etcd) and are not distro-independent.

Each distro and base component are versioned independently with each new version getting it's own package. These versions are not exposed to the user.

Each fcos config version has it's own version which is independent of the versions of the base and distro components that compose it. However a major or minor bump of either component necessitates a corresponding bump in the fcos config version.

internal/ main, non-exported code

base/ Contains distro-agnostic code. Each package here targets only one Ignition spec versions.

distro/ Contains distro-specific code. Each package here can target multiple Ignition versions if it makes sense.

config/ Contains the top level Translate() function that determines which version to parse and emit.

config/common/ Contains the common bits and functions for all spec versions. This means the (un)marshaling helpers and the version+variant struct to be included in every user facing spec

config/vX_Y/ Contains user facing definitions of the spec. Each is composed by combining a base and distro package with the common version+variant. Each of the defines their own translate function to be registered in the config/ package.