hosts/patate/backup/zfs-backup.nix

   1 { pkgs, lib, hostName, ... }:
   2 with builtins;
   3 {
   4   # Show what's happening to the user
   5   systemd.services."zfs-term@" = {
   6     description = "ZFS terminal for: %I";
   7     unitConfig.StopWhenUnneeded = false;
   8     environment.DISPLAY = ":0";
   9     environment.XAUTHORITY = "/home/sevy/.Xauthority";
  10     after = [ "graphical.target" ];
  11     serviceConfig = {
  12       Type = "simple";
  13       PrivateTmp = true;
  14       ExecStart = pkgs.writeShellScript "zfs-term" ''
  15         DESTPOOL=$1
  16         set -eux
  17         ${pkgs.xterm}/bin/xterm -fg white -bg black -fa Monospace -fs 6 \
  18           -title "ZFS backup to: $DESTPOOL" -e "journalctl -f -o short \
  19           -u zfs-force-import@$DESTPOOL \
  20           -u zfs-local-backup-home@$DESTPOOL"
  21       '' + " %I";
  22     };
  23   };
  24   # Force zpool import, even if the disk has not been exported, or has been imported on another computer
  25   systemd.services."zfs-force-import@" = {
  26     description = "ZFS force import: %I";
  27     unitConfig = {
  28       StartLimitBurst = 5;
  29       StartLimitInterval = 200;
  30       StopWhenUnneeded = true;
  31     };
  32     wants = [ "zfs-term@%i.service" ];
  33     bindsTo = [ "sys-subsystem-usb-%i.device" ];
  34     path = lib.mkBefore [ "/run/booted-system/sw" ];
  35     serviceConfig = {
  36       Type = "oneshot";
  37       RemainAfterExit = true;
  38       PrivateTmp = true;
  39       SyslogIdentifier = "zfs-force-import@%i";
  40       Restart = "on-failure";
  41       ExecStart = pkgs.writeShellScript "zfs-force-import" ''
  42         DESTPOOL=$1
  43         set -eux
  44         # Import the zpool, using stable paths
  45         zpool import -d /dev/disk/by-id/ || true
  46         zpool import -lFd /dev/disk/by-id/ "$DESTPOOL" ||
  47         zpool reopen "$DESTPOOL" ||
  48         zpool import -f -d /dev/disk/by-id/ "$DESTPOOL" ||
  49         zpool clear -nFX "$DESTPOOL"
  50       '' + " %I";
  51     };
  52   };
  53   # Prune old snapshots on the backup and send new ones
  54   systemd.services."zfs-local-backup-home@" = {
  55     description = "ZFS backup home, on: %I";
  56     wants = [ "zfs-term@%i.service" ];
  57     after = [ "zfs-force-import@%i.service" ];
  58     requires = [ "zfs-force-import@%i.service" ];
  59     bindsTo = [ "sys-subsystem-usb-%i.device" ];
  60     path = lib.mkBefore [ "/run/booted-system/sw" ];
  61     serviceConfig = rec {
  62       Type = "oneshot";
  63       PrivateTmp = true;
  64       CacheDirectory = [ "zfs-usb-backup/%I" ];
  65       RuntimeDirectory = [ "zfs-usb-backup/%I" ];
  66       User = "sevy";
  67       Group = "users";
  68       SyslogIdentifier = "zfs-local-backup-home@%i";
  69       ExecStartPre = "+" + pkgs.writeShellScript "zfs-local-backup-home-startPre" ''
  70         DESTPOOL=$1
  71         set -eux
  72         if zpool status "$DESTPOOL"; then
  73           zfs allow ${User} bookmark,hold,mount,send ${hostName}/home
  74           zfs allow ${User} bookmark,create,destroy,load-key,mount,mountpoint,receive,rollback,snapshot "$DESTPOOL"/${User}
  75           zpool scrub -p "$DESTPOOL" || true
  76         fi
  77       '' + " %I";
  78       ExecStart = pkgs.writeShellScript "zfs-local-backup-home" ''
  79         set -eu
  80         DESTPOOL=$1
  81         # sanoid is quite conservative:
  82         # by setting hourly=24, a snapshot must be >24 hours old
  83         # and there must been >24 total hourly snapshots,
  84         # or nothing is pruned.
  85         install -D -m 400 /dev/stdin /tmp/sanoid/sanoid.conf <<EOF
  86           [template_remote]
  87           autoprune=true
  88           autosnap=false
  89           process_children_only=false
  90
  91           [$DESTPOOL/${User}/backup/${hostName}/home]
  92           hourly=12
  93           daily=31
  94           monthly=6
  95           recursive=true
  96           use_template=remote
  97         EOF
  98         set -x
  99         ${pkgs.sanoid}/bin/sanoid \
 100           --cache-dir /var/cache/zfs-usb-backup/"$DESTPOOL" \
 101           --configdir /tmp/sanoid \
 102           --prune-snapshots \
 103           --run-dir /run/zfs-usb-backup/"$DESTPOOL" \
 104           --verbose
 105
 106         for dataset in ${hostName}/home; do
 107           ${pkgs.sanoid}/bin/syncoid \
 108             --create-bookmark \
 109             --exclude "home/Downloads" \
 110             --exclude "home/Videos" \
 111             --force-delete \
 112             --no-privilege-elevation \
 113             --no-sync-snap \
 114             --recursive \
 115             --recvoptions "" \
 116             --sendoptions raw  \
 117             --skip-parent \
 118             "$dataset" \
 119             "$DESTPOOL"/${User}/backup/"$dataset"
 120         done
 121       '' + " %I";
 122       ExecStartPost = "+" + pkgs.writeShellScript "zfs-local-backup-home-startPost" ''
 123         DESTPOOL=$1
 124         set -eux
 125         # Only if the zpool still exists to avoid uninterruptible hanging
 126         if zpool status -v "$DESTPOOL"; then
 127           # Scrub the zpool 1 minute (in the background)
 128           zpool scrub "$DESTPOOL"
 129           sleep 60
 130         fi
 131         while zpool status -v "$DESTPOOL"; do
 132           zpool scrub -p "$DESTPOOL" || true
 133           sleep 20
 134           # Export the zpool (to avoid a forced import later on)
 135           zpool export "$DESTPOOL" || true
 136         done
 137         systemctl --no-block stop zfs-term@"$DESTPOOL"
 138       '' + " %I";
 139     };
 140   };
 141   programs.bash.interactiveShellInit = ''
 142     mount-zfs-backup () {
 143       (
 144       set -eux
 145       zpool="$1"
 146       zpool status "$zpool" 2>/dev/null ||
 147       sudo zpool import -d /dev/disk/by-id/ "$zpool"
 148       trap "sudo zpool export $zpool" EXIT
 149       zfs list -rH -t filesystem -o mounted,mountpoint,name "$zpool"/"$USER"/backup |
 150       grep "^no\\s*/" | cut -f 3 | xargs -ortL1 sudo zfs mount -Olv || true
 151       ${pkgs.mate.caja-with-extensions}/bin/caja --browser /mnt/"$zpool"/"$USER"/backup
 152       )
 153     }
 154   '';
 155 }