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

You can boot your system on a "snapshot" from the grub menu.
Supports manual snapshots, snapper, timeshift ...

If you choose to do it, /var/log or even /var must be on a separate subvolume.
Otherwise, make sure your snapshots are writable.
See this ticket for more info.

This project includes its own solution.
Refer to the documentation.

• 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 the type/tags and descriptions/comments of Snapper/Timeshift snapshots.
• Automatically generate grub.cfg if you use the provided Systemd/ OpenRC service.

The package is available in the community repository grub-btrfs

pacman -S grub-btrfs 

grub-btrfs is only available in the Gentoo User Repository (GURU) and not in the official Gentoo repository.
If you have not activated the GURU yet, do so by running:

emerge -av app-eselect/eselect-repository eselect repository enable guru emaint sync -r guru 

If you are using Systemd on Gentoo, make sure the USE-Flag systemd is set. (Either globally in make.conf or in package.use for the package app-backup/grub-btrfs) Without Systemd USE-Flag the OpenRC-daemon of grub-btrfs will be installed.

Emerge grub-btrfs via emerge app-backup/grub-btrfs

grub-btrfs is available in the Kali Linux repository and can be installed with:

apt install grub-btrfs 

Booting into read-only snapshots is fully supported when choosing "btrfs" as file system during a standard Kali Linux installation following this walk-through.

• Run make install or look into Makefile for instructions on where to put each file.
• Run make help to check what options are available.
• Dependencies:
  • btrfs-progs
  • grub
  • bash >4
  • gawk
  • (only when using the daemon)inotify-tools

After installation the grub main menu needs to be generated to make a menuentry for the snapshots sub menu. Depending on the Linux distribution the commands for that are different:

• On Arch Linux or Gentoo use grub-mkconfig -o /boot/grub/grub.cfg.
• On Fedora use grub2-mkconfig -o /boot/grub2/grub.cfg
• On Debian-like distribution update-grub is an alias to grub-mkconfig ...

Once the entry for the sub menu was generated grub-btrfs puts the actual sub menu into the file grub-btrfs.cfg. So to generate snapshot entries in the sub menu it is usually enough to run only the script with sudo /etc/grub.d/41_snapshots-btrfs. Read further below on how to automate this process.

You have the possibility to modify many parameters in /etc/default/grub-btrfs/config.
For further information see config file or man grub-btrfs

Some file locations and command names differ from distribution to distribution. Initially the configuration is set up to work with Arch and Gentoo (and many other distributions) out of the box, which are using the grub-mkconfig command. However, Fedora for example uses a different command, grub2-mkconfig. Edit GRUB_BTRFS_MKCONFIG variable in /etc/default/grub-btrfs/config file to reflect this. (e.g. GRUB_BTRFS_MKCONFIG=/sbin/grub2-mkconfig for Fedora)

On most distributions and installs, the grub installation resides in /boot/grub. If grub is installed in a different place, change the variable GRUB_BTRFS_MKCONFIG in the config file accordingly. For Fedora this is GRUB_BTRFS_GRUB_DIRNAME="/boot/grub2". Also the command to check the grub scripts is different on some system, for Fedora it is GRUB_BTRFS_SCRIPT_CHECK=grub2-script-check

Grub-btrfs comes with a daemon script that automatically updates the grub menu when it sees a snapshot being created or deleted in a directory it is given via command line.

The daemon can be configured by passing different command line arguments to it. The arguments are:

• SNAPSHOTS_DIR This argument specifies the path where grub-btrfsd looks for newly created snapshots and snapshot deletions. It is usually defined by the program used to make snapshots. E.g. for Snapper this would be /.snapshots
• -c / --no-color Disable colors in output.
• -l / --log-file This arguments specifies a file where grub-btrfsd should write log messages.
• -s / --syslog
• -o / --timeshift-old Look for snapshots in /run/timeshift/backup/timeshift-btrfs instead of /run/timeshift/$PID/backup/timeshift-btrfs. This is to be used for Timeshift versions <22.06.
• -t / --timeshift-auto This is a flag to activate the auto detection of the path where Timeshift stores snapshots. Newer versions (>=22.06) of Timeshift mount their snapshots to /run/timeshift/$PID/backup/timeshift-btrfs. Where $PID is the process ID of the currently running Timeshift session. The PID is changing every time Timeshift is opened. grub-btrfsd can automatically take care of the detection of the correct PID and directory if this flag is set. In this case the argument SNAPSHOTS_DIR has no effect.
• -v / --verbose Let the log of the daemon be more verbose
• -h / --help Displays a short help message.

To edit the arguments that are passed to the daemon, use

sudo systemctl edit --full grub-btrfsd

after that the Daemon must be restarted with

sudo systemctl restart grub-btrfsd 

It is also possible to start the daemon without using systemd for troubleshooting purposes for example. If you want to do this, a running daemon should be stopped with

sudo systemctl stop grub-btrfsd 

Then the daemon can be manually run and played around with using the command /usr/bin/grub-btrfsd. For additional information on the daemon script and its arguments, run grub-btrfsd -h and see man grub-btrfsd

To edit the arguments that are passed to the daemon edit the file /etc/conf.d/grub-btrfsd.
After that restart the daemon with

sudo rc-service grub-btrfsd restart 

It is also possible to start the daemon without using OpenRC for troubleshooting purposes for example. If you want to do this, a running daemon should be stopped with

sudo rc-service grub-btrfsd stop 

Then the daemon can be manually run and played around with using the command grub-btrfsd. For additional information on daemon script and its arguments, run grub-btrfsd -h and see man grub-btrfsd

Grub-btrfsd is a daemon daemon that watches the snapshot directory for you and updates the grub menu automatically every time a snapshot is created or deleted. By default this daemon watches the directory /.snapshots for changes (creation or deletion of snapshots) and triggers the grub menu creation if a snapshot is found. Therefore, if Snapper is used with its default directory, the daemon can just be started and nothing needs to be configured. For other configurations like Timeshift, or Snapper with a different directory, see further below.

To start the daemon run

sudo systemctl start grub-btrfsd

To activate it during system startup, run

sudo systemctl enable grub-btrfsd

By default the daemon is watching the directory /.snapshots. If the daemon should watch a different directory, it can be edited with

sudo systemctl edit --full grub-btrfsd 

What should be edited is the /.snapshots-part in the line that says ExecStart=/usr/bin/grub-btrfsd --syslog /.snapshots. So this is what the file should look afterwards:

[Unit] Description=Regenerate grub-btrfs.cfg [Service] Type=simple LogLevelMax=notice # Set the possible paths for `grub-mkconfig` Environment="PATH=/sbin:/bin:/usr/sbin:/usr/bin"# Load environment variables from the configuration EnvironmentFile=/etc/default/grub-btrfs/config # Start the daemon, usage of it is:# grub-btrfsd [-h, --help] [-t, --timeshift-auto] [-l, --log-file LOG_FILE] SNAPSHOTS_DIR# SNAPSHOTS_DIR Snapshot directory to watch, without effect when --timeshift-auto# Optional arguments:# -t, --timeshift-auto Automatically detect Timeshifts snapshot directory# -o, --timeshift-old Activate for timeshift versions <22.06# -l, --log-file Specify a logfile to write to# -v, --verbose Let the log of the daemon be more verbose# -s, --syslog Write to syslog ExecStart=/usr/bin/grub-btrfsd --syslog /.snapshots [Install] WantedBy=multi-user.target

When done, the service should be restarted with

sudo systemctl restart grub-btrfsd 

Newer Timeshift versions create a new directory named after their process ID in /run/timeshift every time they are started. The PID is going to be different every time. Therefore the daemon can not simply watch a directory, it watches /run/timeshift first, if a directory is created it gets Timeshifts current PID, then watches a directory in that newly created directory from Timeshift. Anyhow, to activate this mode of the daemon, --timeshift-auto must be passed to the daemon as a command line argument.

To pass --timeshift-auto to grub-btrfsd, the .service-file of grub-btrfsd can be edited with

sudo systemctl edit --full grub-btrfsd 

The line that says

ExecStart=/usr/bin/grub-btrfsd /.snapshots --syslog 

should be edited into

ExecStart=/usr/bin/grub-btrfsd --syslog --timeshift-auto

So the file looks like this, afterwards:

[Unit] Description=Regenerate grub-btrfs.cfg [Service] Type=simple LogLevelMax=notice # Set the possible paths for `grub-mkconfig` Environment="PATH=/sbin:/bin:/usr/sbin:/usr/bin"# Load environment variables from the configuration EnvironmentFile=/etc/default/grub-btrfs/config # Start the daemon, usage of it is:# grub-btrfsd [-h, --help] [-t, --timeshift-auto] [-l, --log-file LOG_FILE] SNAPSHOTS_DIR# SNAPSHOTS_DIR Snapshot directory to watch, without effect when --timeshift-auto# Optional arguments:# -t, --timeshift-auto Automatically detect Timeshifts snapshot directory# -l, --log-file Specify a logfile to write to# -v, --verbose Let the log of the daemon be more verbose# -s, --syslog Write to syslog ExecStart=/usr/bin/grub-btrfsd --syslog --timeshift-auto [Install] WantedBy=multi-user.target

When done, the service must be restarted with

sudo systemctl restart grub-btrfsd 

Note: You can view your change with systemctl cat grub-btrfsd. To revert all the changes use systemctl revert grub-btrfsd.

Look at this comment
Currently not implemented

To start the daemon run

sudo rc-service grub-btrfsd start 

To activate it during system startup, run

sudo rc-config add grub-btrfsd default 

NOTE: This works also for Timeshift versions < 22.06, the path to watch would be /run/timeshift/backup/timeshift-btrfs/snapshots.

By default the daemon is watching the directory /.snapshots. If the daemon should watch a different directory, it can be edited by passing different arguments to it. Arguments are passed to grub-btrfsd via the file /etc/conf.d/grub-btrfsd. The variable snapshots defines, where the daemon will watch for snapshots.

After editing, the file should look like this:

# Copyright 2022 Pascal Jaeger# Distributed under the terms of the GNU General Public License v3## Where to locate the root snapshots snapshots="/.snapshots"# Snapper in the root directory#snapshots="/run/timeshift/backup/timeshift-btrfs/snapshots" # Timeshift < v22.06## Optional arguments to run with the daemon# Append options to this like this:# optional_args="--syslog --timeshift-auto --verbose"# Possible options are:# -t, --timeshift-auto Automatically detect Timeshifts snapshot directory for timeshift >= 22.06# -o, --timeshift-old Look for snapshots in directory of Timeshift <v22.06 (requires --timeshift-auto)# -l, --log-file Specify a logfile to write to# -v, --verbose Let the log of the daemon be more verbose# -s, --syslog Write to syslog optional_args="--syslog"

After that, the daemon should be restarted with

sudo rc-service grub-btrfsd restart 

Arguments are passed to grub-btrfsd via the file /etc/conf.d/grub-btrfsd. The variable optional_args defines, which optional arguments get passed to the daemon. Uncomment #optional_args+="--timeshift-auto " to pass the command line option --timeshift-auto to it.

After the change, the file should look like this: (Note that there is no need to comment out the snapshots variable. It is ignored when --timeshift-auto is active.)

# Copyright 2022 Pascal Jaeger# Distributed under the terms of the GNU General Public License v3## Where to locate the root snapshots snapshots="/.snapshots"# Snapper in the root directory#snapshots="/run/timeshift/backup/timeshift-btrfs/snapshots" # Timeshift < v22.06## Optional arguments to run with the daemon# Possible options are:# -t, --timeshift-auto Automatically detect Timeshifts snapshot directory for timeshift >= 22.06# -l, --log-file Specify a logfile to write to# -v, --verbose Let the log of the daemon be more verbose# -s, --syslog Write to syslog# Uncomment the line to activate the option optional_args+="--syslog "# write to syslog by default optional_args+="--timeshift-auto "#optional_args+="--log-file /var/log/grub-btrfsd.log "#optional_args+="--verbose "

After that, the daemon should be restarted with

sudo rc-service grub-btrfsd restart 

If you would like the grub-btrfs menu to automatically update on system restart/ shutdown, just add the following script as /etc/local.d/grub-btrfs-update.stop:

#!/usr/bin/env bash description="Update the grub btrfs snapshots menu" name="grub-btrfs-update"depend(){use localmount } bash -c 'if [ -s "${GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}/grub-btrfs.cfg" ]; then /etc/grub.d/41_snapshots-btrfs; else{GRUB_BTRFS_MKCONFIG:-grub-mkconfig} -o{GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}/grub.cfg; fi'

Make your script executable with sudo chmod a+x /etc/local.d/grub-btrfs-update.stop.

• The extension .stop at the end of the filename indicates to the locald-daemon that this script should be run at shutdown. If you want to run the menu update on system startup instead, rename the file to grub-btrfs-update.start
• Works for Snapper and Timeshift

If there are problems don't hesitate to file an issue.

To help the best we would like to know the version of grub-btrfs used. Please run

sudo /etc/grub.d/41_snapshots-btrfs --version

or

sudo /usr/bin/grub-btrfsd --help

to get the currently running version of grub-btrfs.

If you have problems with the daemon, you can run it with the --verbose-flag. To do so you can run

sudo /usr/bin/grub-btrfsd --verbose --timeshift-auto` (for timeshift)# or sudo /usr/bin/grub-btrfsd /.snapshots --verbose` (for snapper)

Or pass --verbose to the daemon using the Systemd .service-file or the OpenRC conf.d file respectively. (see Daemon installation instructions how to do that)

Grub-btrfs uses a rudimentary system of automatic versioning to tell apart different commits. This is helpful when users report problems and it is not immediately clear what version they are using. We therefore have the following script in .git/hooks/pre-commit:

#!/bin/shecho"Doing pre commit hook with version bump" version="$(git describe --tags --abbrev=0)-$(git rev-parse --abbrev-ref HEAD)-$(date -u -Iseconds)"echo"New version is ${version}" sed -i "s/GRUB_BTRFS_VERSION=.*/GRUB_BTRFS_VERSION=${version}/" config git add config

This automatically sets the version in the config-file to [lasttag]-[branch-name]-[current-date-in-UTC]. In order to create a Tag we don't want to have this long version. In this case we set the version manually in config and commit with git commit --no-verify. This avoids running the hook.

• Maxim Baz
• Schievel1
• All contributors