3281fb9132
This documents the input and output format, and also removes some references to Terraform and evaluating NixOS system configurations. It can be used to evaluate anything. Change-Id: I8492cc3e386f89b299469c78e586644ee82a708f Reviewed-on: https://cl.tvl.fyi/c/depot/+/11213 Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
113 lines
2.9 KiB
HCL
113 lines
2.9 KiB
HCL
# SPDX-FileCopyrightText: 2023 The TVL Authors
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#
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# SPDX-License-Identifier: MIT
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# This module deploys a NixOS host by building a system closure
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# located at the specified attribute in the current repository.
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#
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# The closure's derivation path is persisted in the Terraform state to
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# determine after Nix evaluation whether the system closure has
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# changed and needs to be built/deployed.
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#
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# The system configuration is then built (or substituted) on the
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# machine that runs `terraform apply`, then copied and activated on
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# the target machine using `nix-copy-closure`.
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variable "attrpath" {
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description = "attribute set path pointing to the NixOS system closure"
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type = string
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}
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variable "target_host" {
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description = "address (IP or hostname) at which the target is reachable"
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type = string
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}
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variable "entrypoint" {
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description = <<EOT
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Path to a .nix file (or directory containing `default.nix` file)
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that provides the attrset specified in `closure`.
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If unset, asks git for the root of the repository.
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EOT
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type = string
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default = ""
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}
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variable "target_user" {
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description = "username on the target machine"
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type = string
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}
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variable "target_user_ssh_key" {
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description = "SSH key to use for connecting to the target"
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type = string
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default = ""
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sensitive = true
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}
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variable "triggers" {
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type = map(string)
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description = "Triggers for deploy"
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default = {}
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}
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# Fetch the derivation hash for the NixOS system.
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data "external" "nixos_system" {
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program = ["${path.module}/nix-eval.sh"]
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query = {
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attrpath = var.attrpath
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entrypoint = var.entrypoint
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}
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}
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# Deploy the NixOS configuration if anything changed.
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resource "null_resource" "nixos_deploy" {
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connection {
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type = "ssh"
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host = var.target_host
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user = var.target_user
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private_key = var.target_user_ssh_key
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}
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# 1. Wait for SSH to become available.
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provisioner "remote-exec" {
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inline = ["true"]
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}
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# 2. Build NixOS system.
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provisioner "local-exec" {
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command = "nix-build ${data.external.nixos_system.result.drv} --no-out-link"
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}
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# 3. Copy closure to the target.
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provisioner "local-exec" {
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command = "${path.module}/nixos-copy.sh"
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environment = {
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SYSTEM_DRV = data.external.nixos_system.result.drv
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TARGET_HOST = var.target_host
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DEPLOY_KEY = var.target_user_ssh_key
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TARGET_USER = var.target_user
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}
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}
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# 4. Activate closure on the target.
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provisioner "remote-exec" {
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inline = [
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"set -eu",
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"SYSTEM=$(nix-build ${data.external.nixos_system.result.drv} --no-out-link)",
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"sudo nix-env --profile /nix/var/nix/profiles/system --set $SYSTEM",
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"sudo $SYSTEM/bin/switch-to-configuration switch",
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]
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}
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triggers = merge({
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nixos_drv = data.external.nixos_system.result.drv
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target_host = var.target_host
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}, var.triggers)
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}
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output "nixos_drv" {
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value = data.external.nixos_system.result
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}
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