Restic

Restic is a fast and secure backup program. NixOS packages both restic client (program used to make backups) and restic-rest-server (one of the backends to store the backups remotely, "repositories" in restic parlance).

Installing

If you want to manually create restic backups, add restic to environment.systemPackages like so:

environment.systemPackages = with pkgs; [
  restic
];

Configuring

Restic

NixOS provides options to create a systemd timer and a service that will create the backups. See services.restic.backups options and "Backing up" in the restic documentation.

Note that NixOS includes an option to automatically create the repository by specifying    services.restic.backups.<name>.initialize = true;

Restic Rest Server

Restic Rest Server is one of the options for a remote repository. It can be installed by enabling the services.restic.server.enable option. By default the server requires either providing it with htpasswd file or running it without authentication. If provided, the username and password pairs htpassd file will be used to authenticate the restic clients connecting to the server. To run the server without authentication, you can pass the flag using the extraFlags option like this: services.restic.server.extraFlags = [ "--no-auth" ];

Passing the htpasswd file should be done using one of the secret management methods.

Security Wrapper

If you want to back up your system without running restic as root, you can create a user and security wrapper to give restic the capability to read anything on the filesystem as if it were running as root. The following will create the wrapper at /run/wrappers/bin/restic

users.users.restic = {
  isNormalUser = true;
};

security.wrappers.restic = {
  source = "${pkgs.restic.out}/bin/restic";
  owner = "restic";
  group = "users";
  permissions = "u=rwx,g=,o=";
  capabilities = "cap_dac_read_search=+ep";
};