Borg Docker Image

This Docker image includes the BorgBackup client utility and sshfs support. Borg is a deduplicating archiver with compression and authenticated encryption. It's very efficient, doesn't require regular full backups, and supports data pruning.

Docker Hub: https://hub.docker.com/r/pschiffe/borg

Source GitHub repository: https://github.com/pschiffe/docker-borg

If this project is useful to you, please consider sponsoring me to support maintenance and further development. Thank you!

Quick start

First, pull the image to keep it up to date. Then create and run the borg backup container. In this quick start, the /etc and /home directories from the host are bind mounted to the container as read only. These are the directories which will be backed up. The backed up data will be stored in the borg-repo Docker volume, and the data will be protected with the my-secret-pw password. If the host is using SELinux, use the --security-opt label:disable flag. This is because we don't want to relabel the /etc and /home directories, but we do want the container to have access to them. After the backup is done, data will be pruned according to the default policy and checked for errors. Borg runs in verbose mode within the container, which means it will print detailed output from the backup. At the end, the container is deleted. This is done using a separate docker rm command. We do this because the --rm option in docker run would also remove the Docker volumes, which we don't want. By deleting the container and pulling the image from the registry each time, we ensure the container is fresh for each backup run.

docker pull pschiffe/borg
docker run \
  -e BORG_REPO=/borg/repo \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e BACKUP_DIRS=/borg/data \
  -e EXCLUDE='*/.cache*;*.tmp;/borg/data/etc/shadow' \
  -e COMPRESSION=lz4 \
  -e PRUNE=1 \
  -v borg-config:/root \
  -v borg-repo:/borg/repo \
  -v /etc:/borg/data/etc:ro \
  -v /home:/borg/data/home:ro \
  --security-opt label:disable \
  --name borg-backup \
  pschiffe/borg
docker rm borg-backup

More examples

Backup docker volumes to remote location (Borg must be running in server mode at that remote location):

docker run \
  -e BORG_REPO='user@hostname:/path/to/repo' \
  -e ARCHIVE=wordpress-$(date +%Y-%m-%d) \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e BACKUP_DIRS=/borg/data \
  -e COMPRESSION=lz4 \
  -e PRUNE=1 \
  -v borg-config:/root \
  -v mariadb-data:/borg/data/mariadb:ro \
  -v wordpress-data:/borg/data/wordpress:ro \
  --name borg-backup \
  pschiffe/borg

Use sshfs if Borg is not installed on the remote location:

docker run \
  -e SSHFS='user@hostname:/path/to/repo' \
  -e SSHFS_PASSWORD=my-ssh-password \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e BACKUP_DIRS=/borg/data \
  -e COMPRESSION=lz4 \
  -e PRUNE=1 \
  -v borg-config:/root \
  -v mariadb-data:/borg/data/mariadb:ro \
  -v wordpress-data:/borg/data/wordpress:ro \
  --cap-add SYS_ADMIN --device /dev/fuse --security-opt label:disable \
  --name borg-backup \
  pschiffe/borg

Using sshfs with ssh key authentication:

docker run \
  -e SSHFS='user@hostname:/path/to/repo' \
  -e SSHFS_IDENTITY_FILE=/root/ssh-key/key \
  -e SSHFS_GEN_IDENTITY_FILE=1 \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e BACKUP_DIRS=/borg/data \
  -e COMPRESSION=lz4 \
  -e PRUNE=1 \
  -v borg-config:/root \
  -v mariadb-data:/borg/data/mariadb:ro \
  -v wordpress-data:/borg/data/wordpress:ro \
  --cap-add SYS_ADMIN --device /dev/fuse --security-opt label:disable \
  --name borg-backup \
  pschiffe/borg

Restoring files from a specific day to a folder on the host:

docker run \
  -e BORG_REPO='user@hostname:/path/to/repo' \
  -e ARCHIVE=wordpress-2016-05-25 \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e EXTRACT_TO=/borg/restore \
  -e EXTRACT_WHAT=only/this/file \
  -v borg-config:/root \
  -v /opt/restore:/borg/restore \
  --security-opt label:disable \
  --name borg-backup \
  pschiffe/borg

To run a custom Borg command, use the following syntax:

docker run \
  -e BORG_REPO='user@hostname:/path/to/repo' \
  -e BORG_PASSPHRASE=my-secret-pw \
  -e BORG_PARAMS='list ::2016-05-26' \
  -v borg-config:/root \
  --name borg-backup \
  pschiffe/borg

Environment variables

Description of all accepted environment variables follows.

Core variables

BORG_REPO - repository location

ARCHIVE - archive parameter for Borg repository. If empty, defaults to "${HOSTNAME}_$(date +%Y-%m-%d)". For more info see Borg documentation

BACKUP_DIRS - directories to back up

EXCLUDE - paths/patterns to exclude from backup. Paths must be separated by ;. For example: -e EXCLUDE='/my path/one;/path two;*.tmp'

BORG_PARAMS - run custom borg command inside of the container. If this variable is set, default commands are not executed, only the one specified in BORG_PARAMS. For example list or list ::2016-05-26. In both examples, repo is not specified, because borg understands the BORG_REPO env var and uses it by default

BORG_SKIP_CHECK - set to 1 if you want to skip the borg check command at the end of the backup

Compression

COMPRESSION - compression to use. Defaults to lz4. More info

Encryption

BORG_PASSPHRASE - repokey mode password. Defaults to none. Only the repokey mode encryption is supported by this Docker image. More info

Extracting (restoring) files

EXTRACT_TO - directory where to extract (restore) borg archive. If this variable is set, default commands are not executed, only the extraction is done. Repo and archive are specified with BORG_REPO and ARCHIVE variables. More info

EXTRACT_WHAT - subset of files and directories which should be extracted

Pruning

PRUNE - if set, prune the repository after backup. Empty by default. More info

PRUNE_PREFIX - filter data to prune by prefix of the archive. Empty by default - prune all data

KEEP_DAILY - keep specified number of daily backups. Defaults to 7

KEEP_WEEKLY - keep specified number of weekly backups. Defaults to 4

KEEP_MONTHLY - keep specified number of monthly backups. Defaults to 6

SSHFS

SSHFS - sshfs destination in form of user@host:/path. When using sshfs, container needs special permissions: --cap-add SYS_ADMIN --device /dev/fuse and if using SELinux: --security-opt label:disable or apparmor: --security-opt apparmor:unconfined

SSHFS_PASSWORD - password for ssh authentication

SSHFS_IDENTITY_FILE - path to ssh key

SSHFS_GEN_IDENTITY_FILE - if set, generates ssh key pair if SSHFS_IDENTITY_FILE is set and the key file doesn't exist. After generating the key, the public part of the key is printed to stdout and the container stops, so you have the chance to configure the server part before creating the first backup