Baksnapper - backup script for snapper

Baksnapper is a script for backing up snapshots using btrfs send and receive. It currently support backing up snapshots created by snapper or DeNotebak.

Table of content

• Installation
  • From source
  • Arch Linux
• Features
• Usage
• Remote backup over ssh
• Config file
• Systemd
• Limitations

Installation

From source

Clone the reposity

$ git clone git@github.com:plattfot/baksnapper.git
$ cd baksnapper
$ make install PREFIX=<install dir>

Default the scripts will be installed in /usr/bin, the systemd files in /usr/lib/systemd/system and the config file in /etc/baksnapper/example. If you are only packaging up the source please change BSCONF_ROOT to where the final path for baksnapper/example will be. Otherwise the systemd unit files will not work.

For example

$ make install PREFIX=pkg BSCONF_ROOT=/etc

Will install everything into the directory pkg, and the systemd unit file will search for the config files in /etc/baksnapper/.

Arch Linux

Clone this repo and then build the package using the PKBUILD:

$ git clone https://github.com/plattfot/baksnapper.git
$ cd build-aux/baksnapper
$ makepkg -ic

Features

What the latest release supports, and what the goals are for the next release.

• Backup to local destination.
• Backup to remote destination using ssh.
• Backup all snapshots.
• Backup last snapshot only.
• Backup specific snapshot.
• Prune discarded snapshots.
• Delete specific snapshots.
• Delete all snapshots.
• Config file
• Generic systemd files
• Example systemd files
• Backup from remote destination using ssh (Pull)
• Run as none root user.

Usage

First set up snapper to take snapshots of one of your subvolumes, see this page on how to do it for Arch Linux.

Specify source and destination

If you want to back up your snapper snapshots for your home configuration, where the snapshots located in /home/.snapshots, to an external hdd mounted at /mmt/backup.

$ baksnapper /home/.snapshots /mnt/backup/home

This will send the last snapshot of home to `/mnt/backup/home/'.

To backup all snapshots run:

$ baksnapper /home/.snapshots --all /mnt/backup/home

This will mirror what is in /home/.snapshots to /mnt/backup/home.

To remove backups that snapper has discarded add the flag -p/--prune:

$ baksnapper /home/.snapshots --all --prune /mnt/backup/home

To delete specific backups from the backup directory, run:

$ baksnapper /home/.snapshots /mnt/backup/home --delete 1,2,3,63

This will only delete 1,2,3 and 63 if they only contain a info.xml file and a snapshot dir. Otherwise it will issue a warning and skip the directory.

For help use the -h/--help flag

$ baksnapper --help

Snapper config interface (deprecated)

For example if you want to back up your snapshots from your home snapshots to an external hdd mounted at /mnt/backup, run

$ baksnapper -c home /mnt/backup

This will send the last snapshot of home to /mnt/backup/home/

To backup all snapshots run:

$ baksnapper --config home --all /mnt/backup

This will mirror what's in /home/.snapshots to /mnt/backup/home.

To remove backups that snapper has discarded add the flag -p/--prune:

$ baksnapper --config home --all --prune /mnt/backup

To delete specific backups from the backup directory, run:

$ baksnapper --config home /mnt/backup --delete 1,2,3,63

This will only delete 1,2,3 and 63 if they only contain a info.xml file and a snapshot dir. Otherwise it will issue a warning and skip the directory.

For help use the -h/--help flag

$ baksnapper --help

Remote backup over ssh

In order to be able to backup to a remote location you first need to install baksnapper on the remote machine, or at least copy over the baksnapperd script.

Next up is to create a ssh key that baksnapper can use to access the remote machine.

Note: that you need to run this as root, since baksnapper needs root access to copy the snapshots.

$ su -
$ ssh-keygen -t rsa -b 4096 -C "$(whoami)@$(hostname)-$(date -I)"

Leave the passphrase blank and set the file to something like /home/username/.ssh/baksnapper_rsa

Append the public key (the one you just created), to .ssh/authorized_keys for the root account on the remote machine. Open up the .ssh/authorized_keys file on the remote machine and prepend this to the key

command="baksnapperd $SSH_ORIGINAL_COMMAND"

Your file should look something like this after.

command="baksnapperd $SSH_ORIGINAL_COMMAND" ssh-rsa <BAKSNAPPERD-PUBLIC-KEY>

After that test that everything is working by running.

$ (ssh <remote machine> test-connection) && echo "Connection works"

It should print out "Connection works".

If everything is working you can now use remote backup with baksnapper. It uses the same syntax as scp, i.e.

:. For example backup to machine named foo.example.com:

$ baksnapper /home/.snapshots --all foo.example.com:/mnt/backup/home

And for the deprecated snapper config interface:

$ baksnapper --config home --all foo.example.com:/mnt/backup

Tip: If your are using a nonstandard ssh port you can specify it in the .ssh/config, for example

Host foo.example.com
Port 666

Tip: If you have multiple keys, you can specify what key baksnapper should use either with the option:

$ baksnapper /home/.snapshots  --all foo.example.com:/mnt/backup/home --dest-private-key /root/.ssh/<BAKSNAPPERD-PRIVATE-KEY>

And for the deprecated snapper config interface:

$ baksnapper --config home --all foo.example.com:/mnt/backup --private-key /root/.ssh/<BAKSNAPPERD-PRIVATE-KEY>

Or specify that in the Config file using DEST_PRIVATE_KEY or PRIVATE_KEY for the deprecated snapper config interface.

Backup from a remote machine over ssh

You can also pull snapshots from a remote machine to a local location using

$ baksnapper foo.example.com:/home/.snapshots /mnt/backup/home

And you can specify the private key using --src-private-key similar to what you do with --dest-private-key.

The deprecated snapper config interface you can do the same but it is not as intuitive:

$ baksnapper --config home foo.example.com:/mnt/backup --type=pull

Note that /mnt/backup is on the local machine, and --config home is for foo.example.com — There is a reason why this interface is deprecated.

There is also possible to pull backups from one remote machine and send them to another remote machine:

$ baksnapper foo.example.com:/home/.snapshots bar.example.com:/mnt/backup/home

Config file

It can be tiresome to pass the options to baksnapper all the time, you can therefore also create a config files in which you specify the options you wish baksnapper to use. This is also what the systemd unit file is using, more on that later. To read a config file use the command line option -f or --configfile

The config file syntax is pretty simple: = # for comments.

For boolean parameters YES, yes, yes and 1 are interpret as on/true and anything else as off/false.

The supported options are:

• CONFIG (deprecated): The snapper config to backup. Same as --config. (deprecated)
• PATH (deprecated): Destination to backup to. For remote backup use hostname:/backup/to. Where 'hostname' is the name of the server and '/backup/to' is the path to the location it should write the backups to on the remote host.
• SOURCE: Source of the snapshots directory to backup. Same as first positional argument and --source. For remote backup use [user@]hostname:/backup/from. Where user is the username — it is optional and if left out till will use the current user. And hostname is the name of the server and /backup/from is the path to the location where the snapshots are located.
• DEST: Destination for the backup. Same as second positional argument and --dest. For remote backup use [user@]hostname:/backup/to. Where user is the username — it is optional and if left out till will use the current user. And hostname is the name of the server and /backup/to is the path to the location where it should write the backups to on the remote host.
• PRUNE: Prune the backups by deleting snapshots that isn't in the source directory. Same as -p, --prune
• ALL: Send all snapshots in the soruce directory. Same as -a, --all
• VERBOSE: Verbose print out, same as -v, --verbose.
• DAEMON: Name of the baksnapper daemon, default is baksnapperd. Same as --daemon
• TYPE (deprecated): Define if it should push the backup or pull. Default is push. Pull can be used to transfer a backup from a remote server to the current machine.
• PRIVATE_KEY: The private key file to use when connecting to a remote server. Same as --private-key.

Note: Command line options will take precendence over config file options. Note: No variable expansion is supported in the config files, for example you cannot for example type ~/backup, instead you need to expand ~ yourself i.e /home/bob/backup if $USER expands to bob.

Systemd

Baksnapper also supplies a timer and service file so that you can use systemd to handle the backup. For example to use root.bsconf you simply call

systemctl start baksnapper@root.bsconf.timer

Where it looks for config files depends on what BSCONF_ROOT was set to when installing the package, by default this will be /etc/baksnapper/.

Limitations

Known limitations for version 0.4.0.

You cannot pack option flags i.e:

$ baksnapper -apc home /mnt/backup

instead you have to do:

$ baksnapper -a -p -c home /mnt/backup

Config files doesn't support variable expansion,