terraform-provider-ct

terraform-provider-ct allows Terraform to validate a Butane config and transpile to an Ignition config for machine consumption.

Usage

Configure the config transpiler provider (e.g. providers.tf).

provider "ct" {}

terraform {
  required_providers {
    ct = {
      source  = "poseidon/ct"
      version = "0.13.0"
    }
  }
}

Define a Butane config for Fedora CoreOS or Flatcar Linux:

variant: fcos
version: 1.5.0
passwd:
  users:
    - name: core
      ssh_authorized_keys:
        - ssh-key foo

variant: flatcar
version: 1.1.0
passwd:
  users:
    - name: core
      ssh_authorized_keys:
        - ssh-key foo

Define a ct_config data source with strict validation.

data "ct_config" "worker" {
  content      = file("worker.yaml")
  strict       = true
  pretty_print = false

  snippets = [
    file("units.yaml"),
    file("storage.yaml"),
  ]
}

Optionally, template the content.

data "ct_config" "worker" {
  content = templatefile("worker.yaml", {
    ssh_authorized_key = "ssh-ed25519 AAAA...",
  })
  strict       = true
}

Render the ct_config as Ignition for use by machine instances.

resource "aws_instance" "worker" {
  user_data = data.ct_config.worker.rendered
}

Run terraform init to ensure plugin version requirements are met.

$ terraform init

Requirements

• Terraform v0.13+ installed

Versions

Butane configs are converted to the current (according to this provider) stable Ignition config and merged together. For example, poseidon/ct v0.12.0 would convert a Butane Config with variant: fcos and version: 1.2.0 to an Ignition config with version v3.3.0. This relies on Ignition's forward compatibility.

Before poseidon/ct v0.12.0, ct_config content could be a Butane Config or a Container Linux Config (CLC). Before poseidon/ct v0.10.0, Butane configs contained a version that was associated with an Ignition format version. For example, a Butane config with version: 1.0.0 would produce an Ignition config with version 3.0.0.

Development

Binary

To develop the provider plugin locally, build an executable with Go v1.18+.

make