grub-btrfs

This is a version 4.xx of grub-btrfs

BTC donation address: 1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt

Description

Improves Grub by adding "btrfs snapshots" to the Grub menu.

You can start your system on a "snapshot" from the Grub menu.

Supports manual snapshots, snapper, timeshift ...

Warning: booting on read-only snapshots can be tricky

If you choose to do it, /var/log must be on a separate subvolume.

Otherwise, make sure your snapshots are writeable.

See this ticket for more info.

What does grub-btrfs v4.xx do :

• Automatically List snapshots existing on root partition (btrfs).
• Automatically Detect if "/boot" is in separate partition.
• Automatically Detect kernel, initramfs and intel/amd microcode in "/boot" directory on snapshots.
• Automatically Create corresponding "menuentry" in grub.cfg
• Automatically detect snapper and use snapper's snapshot description if available.
• Automatically generate grub.cfg if you use the provided systemd service.

Installation :

Arch Linux

pacman -S grub-btrfs

Manual

• Run make install or look into Makefile for instructions on where to put each file.

NOTE: Generate your Grub menu after installation for the changes to take effect.

On Arch Linux use grub-mkconfig -o /boot/grub/grub.cfg.

Customization:

You have the possibility to modify many parameters in /etc/default/grub-btrfs/config.

• GRUB_BTRFS_SUBMENUNAME="Arch Linux Snapshots"

  Name appearing in the Grub menu. Use distribution information from /etc/os-release by default.

• GRUB_BTRFS_PREFIXENTRY="Snapshot:"

  Add a name ahead your snapshots entries in the Grub menu.

• GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"

  Show full path snapshot or only name in the Grub menu, weird reaction with snapper.

• GRUB_BTRFS_TITLE_FORMAT="p/d/n"

  Custom title, shows/hides p"prefix" d"date" n"name" in the Grub menu, separator "/", custom order available.

• GRUB_BTRFS_LIMIT="50"

  Limit the number of snapshots populated in the GRUB menu.

• GRUB_BTRFS_SUBVOLUME_SORT="+ogen,-gen,path,rootid"

  Sort the found subvolumes by "ogeneration" or "generation" or "path" or "rootid".

  Default: "-rootid" means list snapshot by new ones first

  See Sorting section

• GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND="true"

  Show snapshots found during run "grub-mkconfig".

• GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND="true"

  Show Total number of snapshots found during run "grub-mkconfig".

• GRUB_BTRFS_NKERNEL=("kernel-custom")

  Use it only if you have a custom kernel name

• GRUB_BTRFS_NINIT=("initramfs-custom.img" "initrd.img-custom")

  Use it only if you have a custom initramfs name.

• GRUB_BTRFS_CUSTOM_MICROCODE=("intel-ucode.img")

  Use it only if you have custom microcode.

• GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker")

  Ignore specific path during run "grub-mkconfig".

  For example:

  If path is a directory # Found Snapshot: 2016-03-31 10:24:41 var/lib/docker/btrfs/subvolumes/...

  use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker")

  If path is a subvolume : # Found Snapshot: 2016-03-31 10:24:41 @var/lib/docker/btrfs/subvolumes/...

  use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker")

  You can combine them

  use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker" "var/lib/docker")

• GRUB_BTRFS_SNAPPER_CONFIG="root"

  Snapper's config name to use.

• GRUB_BTRFS_DISABLE="false"

  Disable grub-btrfs.

• GRUB_BTRFS_DIRNAME="grub"

  Name of the grub folder in /boot/, might be grub2 on some distributions.

• GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION="false"

  Change to "true" if you have a boot partition in a different subvolume.

• GRUB_BTRFS_MKCONFIG=grub-mkconfig

  Name or path of the 'grub-mkconfig' executable; might be 'grub2-mkconfig' on some distributions.

• Password protection management for submenu (refer to the Grub documentation)

  • GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS=""

    Add authorized usernames separate by comma (foo,bar)

    When Grub's password protection is enabled, the superuser is authorized by default, it isn't necessary to add it

  • GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU="false"

    Disable authentication support for submenu of Grub-btrfs only (--unrestricted)

    doesn't work if GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS isn't empty

Automatically update grub

If you would like Grub to automatically update when a snapshot is made or deleted:

• Mount your subvolume which contains snapshots to /.snapshots
• Use systemctl start/enable grub-btrfs.path
• grub-btrfs.path automatically (re)generates grub.cfg when a modification appears in /.snapshots

Special thanks for assistance and contributions

• maximbaz
• crossroads1112
• penetal
• wesbarnett
• Psykar
• anyc
• daftaupe
• N-Parsons