77 lines
2.2 KiB
Nix
77 lines
2.2 KiB
Nix
{ config, pkgs, ... }:
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let
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resticPrunePre = pkgs.writeScript "resticPrunePre" ''
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set -ex
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# Recover from an unclean shutdown
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if ${pkgs.zfs}/bin/zfs list tank/backup-old; then
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${pkgs.zfs}/bin/zfs list tank/backup || ${pkgs.zfs}/bin/zfs rename tank/backup-old tank/backup
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fi
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# Undo a prune that has been aborted
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${pkgs.zfs}/bin/zfs destroy tank/backup-prune || true
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${pkgs.zfs}/bin/zfs destroy tank/backup@prune || true
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${pkgs.zfs}/bin/zfs destroy tank/backup-old || true
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# Wait for the restic repository to be unlocked
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while [ -n "$(${pkgs.restic}/bin/restic list locks)" ]; then
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sleep
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fi
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# Clone the Dataset
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${pkgs.zfs}/bin/zfs snapshot tank/backup@prune
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${pkgs.zfs}/bin/zfs clone tank/backup@prune tank/backup-prune
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chown backup:backup /backup-prune
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'';
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resticPrune = pkgs.writeScript "resticPrune" ''
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export RESTIC_REPOSITORY="$RESTIC_REPOSITORY-prune"
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${pkgs.restic} prune --no-cache --max-unused 0
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'';
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resticPrunePost = pkgs.writeScript "resticPrunePost" ''
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set -ex
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# make the original read-only
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${pkgs.zfs}/bin/zfs set readonly=on tank/backup
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# Copy new data over
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${pkgs.restic}/bin/restic copy --no-cache --no-lock
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# Promote the pruned dataset
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${pkgs.zfs}/bin/zfs promote tank/backup-prune
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# Change the dataset names
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${pkgs.zfs}/bin/zfs rename tank/backup tank/backup-old
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${pkgs.zfs}/bin/zfs rename tank/backup-prune tank/backup
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# Destroy the old dataset
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${pkgs.zfs}/bin/zfs destroy -r tank/backup-old
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'';
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in
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{
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users.users.backup = {
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description = "Backup user";
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home = "/backup";
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isSystemUser = true;
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openssh.authorizedKeys.keys = [
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];
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group = "backup";
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};
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users.groups.backup = { };
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systemd.services.restic-prune = {
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enable = true;
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description = "Cleaning up restic backups";
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serviceConfig = {
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ExecStartPre = "!${resticPrunePre}";
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ExecStart = "${resticPrune}";
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ExecStartPost = "!${resticPrunePost}";
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User = "backup";
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Group = "backup";
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Type = "oneshot";
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EnvironmentFile = config.sops.secrets."services/restic/env".owner;
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};
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};
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sops.secrets."services/restic/env".owner = "backup";
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}
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