nixpkgs/nixos/modules/services/backup/sanoid.nix

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{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.sanoid;
datasetSettingsType = with types;
(attrsOf (nullOr (oneOf [ str int bool (listOf str) ]))) // {
description = "dataset/template options";
};
commonOptions = {
hourly = mkOption {
description = "Number of hourly snapshots.";
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type = with types; nullOr ints.unsigned;
default = null;
};
daily = mkOption {
description = "Number of daily snapshots.";
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type = with types; nullOr ints.unsigned;
default = null;
};
monthly = mkOption {
description = "Number of monthly snapshots.";
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type = with types; nullOr ints.unsigned;
default = null;
};
yearly = mkOption {
description = "Number of yearly snapshots.";
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type = with types; nullOr ints.unsigned;
default = null;
};
autoprune = mkOption {
description = "Whether to automatically prune old snapshots.";
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type = with types; nullOr bool;
default = null;
};
autosnap = mkOption {
description = "Whether to automatically take snapshots.";
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type = with types; nullOr bool;
default = null;
};
};
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datasetOptions = rec {
use_template = mkOption {
description = "Names of the templates to use for this dataset.";
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type = types.listOf (types.enum (attrNames cfg.templates));
default = [ ];
};
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useTemplate = use_template;
recursive = mkOption {
description = ''
Whether to recursively snapshot dataset children.
You can also set this to <literal>"zfs"</literal> to handle datasets
recursively in an atomic way without the possibility to
override settings for child datasets.
'';
type = with types; oneOf [ bool (enum [ "zfs" ]) ];
default = false;
};
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process_children_only = mkOption {
description = "Whether to only snapshot child datasets if recursing.";
type = types.bool;
default = false;
};
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processChildrenOnly = process_children_only;
};
# Extract unique dataset names
datasets = unique (attrNames cfg.datasets);
# Function to build "zfs allow" and "zfs unallow" commands for the
# filesystems we've delegated permissions to.
buildAllowCommand = zfsAction: permissions: dataset: lib.escapeShellArgs [
# Here we explicitly use the booted system to guarantee the stable API needed by ZFS
"-+/run/booted-system/sw/bin/zfs"
zfsAction
"sanoid"
(concatStringsSep "," permissions)
dataset
];
configFile =
let
mkValueString = v:
if builtins.isList v then concatStringsSep "," v
else generators.mkValueStringDefault { } v;
mkKeyValue = k: v:
if v == null then ""
else if k == "processChildrenOnly" then ""
else if k == "useTemplate" then ""
else generators.mkKeyValueDefault { inherit mkValueString; } "=" k v;
in
generators.toINI { inherit mkKeyValue; } cfg.settings;
in
{
# Interface
options.services.sanoid = {
enable = mkEnableOption "Sanoid ZFS snapshotting service";
interval = mkOption {
type = types.str;
default = "hourly";
example = "daily";
description = ''
Run sanoid at this interval. The default is to run hourly.
The format is described in
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>.
'';
};
datasets = mkOption {
type = types.attrsOf (types.submodule ({ config, options, ... }: {
freeformType = datasetSettingsType;
options = commonOptions // datasetOptions;
config.use_template = mkAliasDefinitions (mkDefault options.useTemplate or { });
config.process_children_only = mkAliasDefinitions (mkDefault options.processChildrenOnly or { });
}));
default = { };
description = "Datasets to snapshot.";
};
templates = mkOption {
type = types.attrsOf (types.submodule {
freeformType = datasetSettingsType;
options = commonOptions;
});
default = { };
description = "Templates for datasets.";
};
settings = mkOption {
type = types.attrsOf datasetSettingsType;
description = ''
Free-form settings written directly to the config file. See
<link xlink:href="https://github.com/jimsalterjrs/sanoid/blob/master/sanoid.defaults.conf"/>
for allowed values.
'';
};
extraArgs = mkOption {
type = types.listOf types.str;
default = [ ];
example = [ "--verbose" "--readonly" "--debug" ];
description = ''
Extra arguments to pass to sanoid. See
<link xlink:href="https://github.com/jimsalterjrs/sanoid/#sanoid-command-line-options"/>
for allowed options.
'';
};
};
# Implementation
config = mkIf cfg.enable {
services.sanoid.settings = mkMerge [
(mapAttrs' (d: v: nameValuePair ("template_" + d) v) cfg.templates)
(mapAttrs (d: v: v) cfg.datasets)
];
systemd.services.sanoid = {
description = "Sanoid snapshot service";
serviceConfig = {
ExecStartPre = (map (buildAllowCommand "allow" [ "snapshot" "mount" "destroy" ]) datasets);
ExecStopPost = (map (buildAllowCommand "unallow" [ "snapshot" "mount" "destroy" ]) datasets);
ExecStart = lib.escapeShellArgs ([
"${pkgs.sanoid}/bin/sanoid"
"--cron"
"--configdir"
(pkgs.writeTextDir "sanoid.conf" configFile)
] ++ cfg.extraArgs);
User = "sanoid";
Group = "sanoid";
DynamicUser = true;
RuntimeDirectory = "sanoid";
CacheDirectory = "sanoid";
};
# Prevents missing snapshots during DST changes
environment.TZ = "UTC";
after = [ "zfs.target" ];
startAt = cfg.interval;
};
};
meta.maintainers = with maintainers; [ lopsided98 ];
}