Automatic Backups With Restic

Backups should be automatic - fire and forget. This guide shows you how it is done!

First of - what is restic? It’s a relatively new backup program for Linux and Windows. You can get your copy at the release page or in your repository.

Act 1: The setup

The way restic works we need a “remote” repository. Bare a little with me before typing anything in your console jockey. We will automate this stuff in a moment.

So you can initialize the repo by issuing the following command: restic init --repo /src/backup But did you know that restic also reads the environment variable RESTIC_REPOSITORY?

There is also RESTIC_PASSWORD_FILE or RESTIC_PASSWORD if you like your password better hanging around in the ENV.

Here is what we will do - we will create a file called restic_env e.g. in /etc/backup/

/etc/backup/restic_env:

export RESTIC_REPOSITORY="/path/to/repo"
export RESTIC_PASSWORD_FILE="/etc/restic/pw.txt"

For this to work we need some file that will source this in our current env; this will be our backup script:

/etc/backup/auto_backup.sh:

#!/usr/bin/env bash
# This script is intended to be run by a systemd timer

# Exit on failure or pipefail
set -e -o pipefail

#Set this to any location you like
BACKUP_PATHS = "/home"

BACKUP_TAG=systemd.timer

# How many backups to keep.
RETENTION_DAYS=14
RETENTION_WEEKS=16
RETENTION_MONTHS=18
RETENTION_YEARS=3

source /etc/backup/restic_env

# Remove locks in case other stale processes kept them in
restic unlock &
wait $!

#Do the backup

restic backup \
       --verbose
       --one-file-system \
       --tag $BACKUP_TAG \
       $BACKUP_PATH &

wait $!

# Remove old Backups

restic forget \
       --verbose \
       --tag $BACKUP_TAG \
       --prune \
       --keep-daily $RETENTION_DAYS \
       --keep-weekly $RETENTION_WEEKS \
       --keep-monthly $RETENTION_MONTHS \
       --keep-yearly $RETENTION_YEARS &
wait $!

# Check if everything is fine
restic check &
wait $!

echo "Backup done!"

It’s prudent to run your first backup with this command manually so chmod +x and give it a try.

Act 2: The Automation

Systemd needs a timer and a unit to fire up our little script like cron did in the golden days - and hey if you are still an old school operator using chron just skip ahead; you know what you are doing - for everybody else here is the timer:

/etc/systemd/system/backup.timer:

[Unit]
Description=Backup on schedule

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target

And the service file:

/etc/systemd/system/backup.service:

[Unit]
Description=Backup with restic
[Service]
Type=simple
Nice=10
ExecStart=/etc/backup/restic_backup.sh
#$HOME must be set for restic to find /root/.cache/restic/
Environment="HOME=/root"

Act 3 : The Execution

Now all is set and done - to activate you only have to run this one command: systemctl enable backup.timer --now

You can now use systemctl list-timers | grep backup to the schedule and check on the service using systemctl status backup with systemctl start backup you can even start it manually.

To follow up on your backups just use journalctl -u backup.service

FIN

If you have a comment or want to add something just send me an email.

Bithive out!