kcinnayste/duplicity repository overview

⁠Supported tags and respective Dockerfile links

⁠What is Duplicity?

duplicity⁠ backup tool.

Features of this Docker image:

• Small: Built using alpine⁠.
• Simple: Most common cases are explained below and require minimal setup.
• Secure: Runs non-root by default (use randomly chosen UID 1896), and meant to run as any user.

⁠Usage

For the general command-line syntax, do:

$ docker run --rm kcinnayste/duplicity --help

In general you...

• Must mount what you want to backup or where you want to restore a backup.
• Should mount /home/duplicity/.cache/duplicity as writable somewhere (if not cached, duplicity will have to recreate it from the remote repository which may require decrypting the backup contents⁠). Note it may be quite large and contains metadata info about files you've backed up in clear text.
• Should mount /home/duplicity/.gnupg as writable somewhere (that directory is used to validate incremental backups and shouldn't be necessary to restore your backup if you follows steps below).
• Should specify duplicity flag --allow-source-mismatch because Docker has a random host for each container.
• Could set environment variable PASSPHRASE, unless you want to type it manually in the prompt (remember then to add -it).
• May have to mount a few other files for authentication (see examples below).

Example of commands you may want to run periodically to back up with good clean-up/maintenance (see below for various storage options):

     $ docker run --rm ... kcinnayste/duplicity --full-if-older-than=6M source_directory target_url
     $ docker run --rm ... kcinnayste/duplicity remove-older-than 6M --force target_url
     $ docker run --rm ... kcinnayste/duplicity cleanup --force target_url

This would do:

1. A full backup every 6 months so that restoration is a lot faster and for cleanup to work, and incremental backups the rest of the time.
2. Delete backups older than 6 months (doesn't break incremental backups).
3. Delete files from failed sessions (if any).

⁠Backup via SSH example

at the first, you have to generate the SSH-Keys and add the Target to the known_hosts.

$ docker run --rm -it \
          -v $PWD/sshParams/known_hosts:/home/duplicity/.ssh \
          kcinnayste/duplicity \
          --add-known-host example.com \
          --generate-ssh-key

Supposing you've an SSH access to some machine, you can:

    $ docker run --rm -it \
          -e PASSPHRASE=P4ssw0rd \
          -v $PWD/.cache:/home/duplicity/.cache/duplicity \
          -v $PWD/.gnupg:/home/duplicity/.gnupg \
          -v $PWD/sshParams/known_hosts:/home/duplicity/.ssh \
          -v /:/data:ro \
          kcinnayste/duplicity \
          --full-if-older-than=6M --allow-source-mismatch \
          --rsync-options='-e "ssh -i /id_rsa"' \
          /data scp://[email protected]//some_dir

⁠Alias

Here is a simple alias that should work in most cases:

$ alias duplicity='docker run --rm --user=root -v ~/.ssh/id_rsa:/home/duplicity/.ssh/id_rsa:ro -v ~/.boto:/home/duplicity/.boto:ro -v ~/.gnupg:/home/duplicity/.gnupg -v /:/mnt:ro -e PASSPHRASE=$PASSPHRASE wernight/duplicity duplicity $@'

Now you should be able to run duplicity almost as if it were installed, example:

$ PASSPHRASE=123456 duplicity --progress /mnt rsync://[email protected]/some_dir

⁠See also

• duplicity man⁠ page
• duplicity back-up how-to - Ubuntu⁠
• How To Use Duplicity with GPG to Securely Automate Backups on Ubuntu | DigitalOcean⁠