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.

poseidon/ct	Butane variant	Butane version	Ignition verison
0.13.x	fcos	1.0.0, 1.1.0, 1.2.0, 1.3.0, 1.4.0, 1.5.0	3.4.0
0.13.x	flatcar	1.0.0, 1.1.0	3.4.0
0.12.x	fcos	1.0.0, 1.1.0, 1.2.0, 1.3.0, 1.4.0	3.3.0
0.12.x	flatcar	1.0.0	3.3.0

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.

terraform-provider-ct	CLC to Ignition	Butane to Ignition
0.11.x	Renders 2.3.0	Butane (1.0, 1.1, 1.2, 1.3, 1.4) -> Ignition 3.3
0.10.x	Renders 2.3.0	Butane (1.0, 1.1, 1.2, 1.3, 1.4) -> Ignition 3.3
0.9.x	Renders 2.3.0	Butane (1.0, 1.1, 1.2, 1.3, 1.4) -> Ignition (3.0, 3.1, 3.2, 3.2, 3.3)
0.8.x	Renders 2.3.0	Butane (1.0, 1.1, 1.2, 1.3) -> Ignition (3.0, 3.1, 3.2, 3.2)
0.7.x	Renders 2.3.0	Butane (1.0, 1.1, 1.2) -> Ignition (3.0, 3.1, 3.2)
0.6.x	Renders 2.3.0	Butane (1.0, 1.1) -> Ignition (3.0, 3.1)
0.5.x	Renders 2.2.0	Butane 1.0.0 -> Ignition 3.0.0
0.4.x	Renders 2.2.0	Butane 1.0.0 -> Ignition 3.0.0
0.3.x	Renders 2.2.0	NA
0.2.x	Renders 2.0.0	NA

Development

Binary

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

make