NixOS config for backrest

This is more of a NixOS issue, but I thought I'd ask here. I'm having trouble getting the service to start, unknown file/folder backrest when starting the systemd service. Has anyone got a working Nix config that defines the backrest service that I could have a look at please?

This works for me. I have rclone, restic and backrest in my global packages.

  # defaults to port 9898
  systemd.services.backrest = {
    description = "Launch backrest to take care of backups";
    wantedBy = ["multi-user.target"];
    requires = ["network-online.target"];
    script = "backrest";
    path = [pkgs.backrest pkgs.rclone];
    environment = {
      BACKREST_PORT = "0.0.0.0:9898";
    };
    serviceConfig = {
      Type = "simple";
      User = "stschiff";
      # AmbientCapabilities = "CAP_DAC_READ_SEARCH";
      # CapabilityBoundingSet = "CAP_DAC_READ_SEARCH";
      # ExecStart = "backrest";
      # It’s often a good idea to mark the service active after the command finishes.
      # RemainAfterExit = true;
    };
  };

Perfect thank you @chrisheib works like a charm.

Awesome! If I knew how it would probably be a good idea to include this in the package itself or a nixos config entry, as others might use this too.

That would be first prize. The package is here Can you help at all @interdependence ? (maintainer of nixos package)

Hi all, jumping on to this thread-- NixOS is an area of interest for me, I keep hearing about it. @interdependence if there's anything I can do to add official support for updates etc this is something I'm happy to discuss.

The releaser tool I use https://goreleaser.com/customization/nix/ does provide support for nix releases-- but looks like this would be a user repo as opposed to the official package you've published.

Side note: noticing some tests are skipped, best practice for backrest might be to focus on running the restic integration tests https://github.com/garethgeorge/backrest/tree/main/pkg/restic , they add value to run on each install as they'll assert that backrest is compatible with the version of restic it's getting from restic packages. The rest of the tests should be getting run by my release pipeline and wouldn't be expected to ever behave (particularly) differently on user systems-- beyond some flakes as you've observed.

Seeing that list did prompt me to spend a bit of time deflaking tests :) I've managed to improve a few of them, specially TestRunCommand should be much less flaky now.

Hi,

I made a Backrest module for NixOS some time ago, but didn't bother creating a PR for this in nixpkgs.

However, I now took a few minutes to do it over here : https://github.com/NixOS/nixpkgs/pull/422093

Cheers,

Hey everyone,

I'm glad to hear that people are actually using the package! I don't actually use it myself at the moment and packaged it mainly to learn how Nixpkgs works. That being said I will have a look at the module PR.

Regarding the skipped tests in the package: I will have a closer look at them next time there is an version upgrade for Backrest. I didn't spend too much time debugging them, but usually these fail due to the sandboxed build environment.

Building on the solution from @chrisheib I created this module for my NixOs config as backrest-service.nix:

# Importing this file adds Backrest as a systemd service to the system.
{
  config,
  pkgs,
  ...
}: {
  environment.systemPackages = with pkgs; [
    restic
    rclone
    backrest
  ];

  systemd.services.backrest = {
    description = "Backrest service";
    wantedBy = ["multi-user.target"];
    requires = ["network-online.target"];
    script = "backrest";
    path = [pkgs.backrest pkgs.rclone];
    environment = {
      BACKREST_PORT = "127.0.0.1:9898";
    };
    serviceConfig = {
      Type = "simple";
      User = "root";
      Group = "root";
    };
  };
}

It starts backrest as root, because I want also to backup /root, limits access to localhost and ensures that the required packages are installed.

This can be imported in configuration.nix like this:

  imports = [
    relative/path/to/backrest-service.nix
  ];

The only thing I couldn't figure out is how I can make Backrest use local time. All times are displayed in UTC on the NixOS system, but that's no real problem. Another system shows the same snapshots as correct local time, which means the data in the repo is fine.