leocp1 / terraform-provider-packernix

Terraform Provider for Nix with Packer

A Terraform provider for deploying NixOS configurations with Packer.

Approach

• Build a NixOS configuration with a Terraform wrapped version of nix-build.
• Build a machine image from this configuration with a Terraform wrapped version of Packer.
• Deploy this image with Terraform.

Compared to other approaches this has a few benefits:

• If the NixOS or Packer configuration changes, terraform apply will detect it and redeploy.
• Machine images make redeploying instances of the same configuration fast.
• Adding support for a new cloud provider only requires writing a Packer builder plugin, a NixOS module, and a Packer template.

Building

A nixpkgs style derivation is in default.nix. The derivation has an unlisted dependency on having a packer in your PATH with access to the packer-provisioner-fakessh plugin and any other provider specific plugins used.

To try out the plugin with AWS, run

nix-shell shell.nix

Documentation

The website directory contains terraform-website compatible markdown files.

Cloud Support

| Provider | Packer template | packer-builder-delete- | NixOS module | | ........ | :.............: | :......................: | :..........: | | vultr | ✔️ | ✔️ | ✔️ |

Testing

The provider uses the usual go test command for testing:

• Creating NixOS images can be slow, so consider disabling the timeout with -timeout 0.
• Most of the tests require TF_ACC=true to run.
• Set TF_LOG=INFO or higher to view command output.

The location of the share directory can be overridden with the TERRAFORM_PACKERNIX_SHARE environment variable. This directory is expected to contain the following directories from the repository root.

• nixos/modules: Cloud provider specific configuration.
• nixos/template: Template files for the OS data source.
• packer: Packer template generator Nix functions.

The packer directory is also expected to be added to the Nix store with name packer, so running

nix-store --recursive --add-fixed sha256 "$TERRAFORM_PACKERNIX_SHARE/packer"

may be necessary.

Licenses

All Go source files (files with extension .go) in this repository are licensed under the Mozilla Public License 2.0.

All Nix source files (files with extension .nix) in this repository, all shell scripts (files with extension .sh) in this repository, and all files under the pkgs directory are licensed under the MIT License.

All test data files (files under a testdata directory) in this repository not covered by the previous two paragraphs and the provider documentation (files under the root website directory and files with extension .md in the top level directory) are licensed under the CC0 License 1.0 Universal.