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Use custom restic backup module

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Cyryl Płotnicki 2022-07-02 09:56:25 +01:00
parent cf0fbcc594
commit acd0d41b3a
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6
nixos/backups.nix
View file

@ -9,6 +9,8 @@ let
];
in {
disabledModules = [ "services/backup/restic.nix" ];
imports = [ services/backup/restic.nix ];
services = {
restic.backups.home-to-bolty = {
passwordFile = "/etc/nixos/secrets/restic-password-bolty";
@ -16,6 +18,8 @@ in {
repository = "rest:http://bolty:8000/";
timerConfig = { OnCalendar = "hourly"; };
extraBackupArgs = extraArgs;
niceness = 19;
ioSchedulingClass = "idle";
};
restic.backups.home-to-b2 = {
@ -25,6 +29,8 @@ in {
timerConfig = { OnCalendar = "hourly"; };
extraBackupArgs = extraArgs;
environmentFile = "/etc/nixos/secrets/b2-env";
niceness = 19;
ioSchedulingClass = "idle";
};
};
}

352
nixos/services/backup/restic.nix Normal file
View file

@ -0,0 +1,352 @@
{ config, lib, pkgs, utils, ... }:
with lib;
let
# Type for a valid systemd unit option. Needed for correctly passing "timerConfig" to "systemd.timers"
inherit (utils.systemdUtils.unitOptions) unitOption;
in {
options.services.restic.backups = mkOption {
description = ''
Periodic backups to create with Restic.
'';
type = types.attrsOf (types.submodule ({ config, name, ... }: {
options = {
passwordFile = mkOption {
type = types.str;
description = ''
Read the repository password from a file.
'';
example = "/etc/nixos/restic-password";
};
environmentFile = mkOption {
type = with types; nullOr str;
# added on 2021-08-28, s3CredentialsFile should
# be removed in the future (+ remember the warning)
default = config.s3CredentialsFile;
description = ''
file containing the credentials to access the repository, in the
format of an EnvironmentFile as described by systemd.exec(5)
'';
};
s3CredentialsFile = mkOption {
type = with types; nullOr str;
default = null;
description = ''
file containing the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
for an S3-hosted repository, in the format of an EnvironmentFile
as described by systemd.exec(5)
'';
};
rcloneOptions = mkOption {
type = with types; nullOr (attrsOf (oneOf [ str bool ]));
default = null;
description = ''
Options to pass to rclone to control its behavior.
See <link xlink:href="https://rclone.org/docs/#options"/> for
available options. When specifying option names, strip the
leading <literal>--</literal>. To set a flag such as
<literal>--drive-use-trash</literal>, which does not take a value,
set the value to the Boolean <literal>true</literal>.
'';
example = {
bwlimit = "10M";
drive-use-trash = "true";
};
};
rcloneConfig = mkOption {
type = with types; nullOr (attrsOf (oneOf [ str bool ]));
default = null;
description = ''
Configuration for the rclone remote being used for backup.
See the remote's specific options under rclone's docs at
<link xlink:href="https://rclone.org/docs/"/>. When specifying
option names, use the "config" name specified in the docs.
For example, to set <literal>--b2-hard-delete</literal> for a B2
remote, use <literal>hard_delete = true</literal> in the
attribute set.
Warning: Secrets set in here will be world-readable in the Nix
store! Consider using the <literal>rcloneConfigFile</literal>
option instead to specify secret values separately. Note that
options set here will override those set in the config file.
'';
example = {
type = "b2";
account = "xxx";
key = "xxx";
hard_delete = true;
};
};
rcloneConfigFile = mkOption {
type = with types; nullOr path;
default = null;
description = ''
Path to the file containing rclone configuration. This file
must contain configuration for the remote specified in this backup
set and also must be readable by root. Options set in
<literal>rcloneConfig</literal> will override those set in this
file.
'';
};
repository = mkOption {
type = with types; nullOr str;
default = null;
description = ''
repository to backup to.
'';
example = "sftp:backup@192.168.1.100:/backups/${name}";
};
repositoryFile = mkOption {
type = with types; nullOr path;
default = null;
description = ''
Path to the file containing the repository location to backup to.
'';
};
paths = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
description = ''
Which paths to backup. If null or an empty array, no
backup command will be run. This can be used to create a
prune-only job.
'';
example = [ "/var/lib/postgresql" "/home/user/backup" ];
};
timerConfig = mkOption {
type = types.attrsOf unitOption;
default = { OnCalendar = "daily"; };
description = ''
When to run the backup. See man systemd.timer for details.
'';
example = {
OnCalendar = "00:05";
RandomizedDelaySec = "5h";
};
};
user = mkOption {
type = types.str;
default = "root";
description = ''
As which user the backup should run.
'';
example = "postgresql";
};
extraBackupArgs = mkOption {
type = types.listOf types.str;
default = [ ];
description = ''
Extra arguments passed to restic backup.
'';
example = [ "--exclude-file=/etc/nixos/restic-ignore" ];
};
extraOptions = mkOption {
type = types.listOf types.str;
default = [ ];
description = ''
Extra extended options to be passed to the restic --option flag.
'';
example = [
"sftp.command='ssh backup@192.168.1.100 -i /home/user/.ssh/id_rsa -s sftp'"
];
};
initialize = mkOption {
type = types.bool;
default = false;
description = ''
Create the repository if it doesn't exist.
'';
};
pruneOpts = mkOption {
type = types.listOf types.str;
default = [ ];
description = ''
A list of options (--keep-* et al.) for 'restic forget
--prune', to automatically prune old snapshots. The
'forget' command is run *after* the 'backup' command, so
keep that in mind when constructing the --keep-* options.
'';
example = [
"--keep-daily 7"
"--keep-weekly 5"
"--keep-monthly 12"
"--keep-yearly 75"
];
};
dynamicFilesFrom = mkOption {
type = with types; nullOr str;
default = null;
description = ''
A script that produces a list of files to back up. The
results of this command are given to the '--files-from'
option.
'';
example = "find /home/matt/git -type d -name .git";
};
backupPrepareCommand = mkOption {
type = with types; nullOr str;
default = null;
description = ''
A script that must run before starting the backup process.
'';
};
backupCleanupCommand = mkOption {
type = with types; nullOr str;
default = null;
description = ''
A script that must run after finishing the backup process.
'';
};
niceness = mkOption {
description =
"Niceness for local instances of btrbk. Also applies to remote ones connecting via ssh when positive.";
type = types.ints.between (-20) 19;
default = 10;
};
ioSchedulingClass = mkOption {
description =
"IO scheduling class for btrbk (see ionice(1) for a quick description). Applies to local instances, and remote ones connecting by ssh if set to idle.";
type = types.enum [ "idle" "best-effort" "realtime" ];
default = "best-effort";
};
};
}));
default = { };
example = {
localbackup = {
paths = [ "/home" ];
repository = "/mnt/backup-hdd";
passwordFile = "/etc/nixos/secrets/restic-password";
initialize = true;
};
remotebackup = {
paths = [ "/home" ];
repository = "sftp:backup@host:/backups/home";
passwordFile = "/etc/nixos/secrets/restic-password";
extraOptions = [
"sftp.command='ssh backup@host -i /etc/nixos/secrets/backup-private-key -s sftp'"
];
timerConfig = {
OnCalendar = "00:05";
RandomizedDelaySec = "5h";
};
};
};
};
config = {
warnings = mapAttrsToList (n: v:
"services.restic.backups.${n}.s3CredentialsFile is deprecated, please use services.restic.backups.${n}.environmentFile instead.")
(filterAttrs (n: v: v.s3CredentialsFile != null)
config.services.restic.backups);
systemd.services = mapAttrs' (name: backup:
let
extraOptions = concatMapStrings (arg: " -o ${arg}") backup.extraOptions;
resticCmd = "${pkgs.restic}/bin/restic${extraOptions}";
filesFromTmpFile = "/run/restic-backups-${name}/includes";
backupPaths = if (backup.dynamicFilesFrom == null) then
if (backup.paths != null) then
concatStringsSep " " backup.paths
else
""
else
"--files-from ${filesFromTmpFile}";
pruneCmd = optionals (builtins.length backup.pruneOpts > 0) [
(resticCmd + " forget --prune "
+ (concatStringsSep " " backup.pruneOpts))
(resticCmd + " check")
];
# Helper functions for rclone remotes
rcloneRemoteName =
builtins.elemAt (splitString ":" backup.repository) 1;
rcloneAttrToOpt = v:
"RCLONE_" + toUpper (builtins.replaceStrings [ "-" ] [ "_" ] v);
rcloneAttrToConf = v:
"RCLONE_CONFIG_" + toUpper (rcloneRemoteName + "_" + v);
toRcloneVal = v: if lib.isBool v then lib.boolToString v else v;
in nameValuePair "restic-backups-${name}" ({
environment = {
RESTIC_PASSWORD_FILE = backup.passwordFile;
RESTIC_REPOSITORY = backup.repository;
RESTIC_REPOSITORY_FILE = backup.repositoryFile;
} // optionalAttrs (backup.rcloneOptions != null) (mapAttrs'
(name: value:
nameValuePair (rcloneAttrToOpt name) (toRcloneVal value))
backup.rcloneOptions)
// optionalAttrs (backup.rcloneConfigFile != null) {
RCLONE_CONFIG = backup.rcloneConfigFile;
} // optionalAttrs (backup.rcloneConfig != null) (mapAttrs'
(name: value:
nameValuePair (rcloneAttrToConf name) (toRcloneVal value))
backup.rcloneConfig);
path = [ pkgs.openssh ];
restartIfChanged = false;
serviceConfig = {
Type = "oneshot";
ExecStart = (optionals (backupPaths != "") [
"${resticCmd} backup --cache-dir=%C/restic-backups-${name} ${
concatStringsSep " " backup.extraBackupArgs
} ${backupPaths}"
]) ++ pruneCmd;
User = backup.user;
RuntimeDirectory = "restic-backups-${name}";
CacheDirectory = "restic-backups-${name}";
CacheDirectoryMode = "0700";
Nice = backup.niceness;
IOSchedulingClass = backup.ioSchedulingClass;
} // optionalAttrs (backup.environmentFile != null) {
EnvironmentFile = backup.environmentFile;
};
} // optionalAttrs (backup.initialize || backup.dynamicFilesFrom != null
|| backup.backupPrepareCommand != null) {
preStart = ''
${optionalString (backup.backupPrepareCommand != null) ''
${pkgs.writeScript "backupPrepareCommand"
backup.backupPrepareCommand}
''}
${optionalString (backup.initialize) ''
${resticCmd} snapshots || ${resticCmd} init
''}
${optionalString (backup.dynamicFilesFrom != null) ''
${
pkgs.writeScript "dynamicFilesFromScript"
backup.dynamicFilesFrom
} > ${filesFromTmpFile}
''}
'';
} // optionalAttrs (backup.dynamicFilesFrom != null
|| backup.backupCleanupCommand != null) {
postStart = ''
${optionalString (backup.backupCleanupCommand != null) ''
${pkgs.writeScript "backupCleanupCommand"
backup.backupCleanupCommand}
''}
${optionalString (backup.dynamicFilesFrom != null) ''
rm ${filesFromTmpFile}
''}
'';
})) config.services.restic.backups;
systemd.timers = mapAttrs' (name: backup:
nameValuePair "restic-backups-${name}" {
wantedBy = [ "timers.target" ];
timerConfig = backup.timerConfig;
}) config.services.restic.backups;
};
}