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Backing up your dedicated server on Scaleway Object Storage with Duplicity

Reviewed on 24 April 2025 • Published on 13 October 2018

duplicity
backup
gpg
s3

In this article, we will learn how to back up data from a Scaleway Instance, using Scaleway’s Object Storage service and Duplicity. Duplicity is a free and open-source tool that backs up folders to a remote server, in this case, an Object Storage bucket. Using libsync and GPG, Duplicity can make space-efficient encrypted backups.

Our objectives are to:

Make production-ready automatic backups of our data.
Save cost using bandwidth and space-efficient incremental backups.
Preserve a robust layer of security and privacy with asymmetrical encryption.

To achieve this, we will:

Create a bucket in Scaleway’s Object Storage
Install Duplicity
Generate a GPG key
Combine Duplicity and Scaleway Object Storage

Although this tutorial focuses on backing up an Instance, you can also back up a dedicated server with Duplicity. When you are using a Scaleway Dedibox or a Scaleway Elastic Metal server, the data transfer is free of charge within the same region.

Before you startLink to this anchor

To complete the actions presented below, you must have:

A Scaleway account logged into the console
Owner status or IAM permissions allowing you to perform actions in the intended Organization
A valid API key
An Instance running Ubuntu or Debian

Creating an Object Storage bucketLink to this anchor

Follow the instructions to create an Object Storage bucket. This bucket will be used to back up your Instance’s data.

Installing software requirementsLink to this anchor

In this step, we install the various software needed. As well as installing Duplicity itself, Duplicity needs us to generate a GPG key so that it can encrypt the data. For GPG key generation, we need to create some entropy, so we also install Haveged to generate a small amount of entropy.

Note

You can find the link to the latest version of Duplicity on their website. You may replace the link used with wget (and therefore tar and cd) if a newer version is available.

Run the following command to update the APT package manager, upgrade the software already installed on the server and download and install Duplicity and the other required software:

sudo apt update && sudo apt upgrade -y
sudo apt install -y python3-pip gnupg2 haveged duplicity

Creating a GPG keyLink to this anchor

Generate the GPG key with the following command.

gpg --full-generate-key

Enter and remember a passphrase. You are asked to define the characteristics of your keys. We go with the default settings:

What kind of key you want: (1) RSA and RSA (default)
What key size you want: (3072)
How long the key should be valid: 0 = key does not expire

GPG then asks for a name for your key, an address, and a description.

gpg --full-generate-key
gpg (GnuPG) 2.1.18; Copyright (C) 2017 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Please select what kind of key you want:
  (1) RSA and RSA (default)
  (2) DSA and Elgamal
  (3) DSA (sign only)
  (4) RSA (sign only)
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (3072) 3072
Requested keysize is 3072 bits
Please specify how long the key should be valid.
  0 = key does not expire
  <n>  = key expires in n days
  <n>w = key expires in n weeks
  <n>m = key expires in n months
  <n>y = key expires in n years
Key is valid for? (0) 0
Key does not expire at all
Is this correct? (y/N) y
GnuPG needs to construct a user ID to identify your key.
Real name: backups
Email address: me@scaleway.com
Comment: Scaleway Object Storage backups
You selected this USER-ID:
  backups (Scaleway Object Storage backups) <me@scaleway.com>
Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
gpg: key XXXXXXXXXXXXXXXX marked as ultimately trusted
public and secret key created and signed.
pub   rsa3072  2020-03-26 [SC]
  XXXXXXXXXXXXX-FINGERPRINT-XXXXXXXXXXXXXX
uid                      backups (Scaleway Object Storage backups) <me@scaleway.com>
sub   rsa3072  2020-03-26 [E]

Copy the GPG key fingerprint (its location in the output is shown above), which could be an 8, 16 or 40 char long hash. You can also find the fingerprint of your key with the following command:

gpg --list-keys
gpg: checking the trustdb
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid: 1  signed: 0  trust: 0-, 0q, 0n, 0m, 0f, 1u
/home/me/.gnupg/pubring.kbx
------------------------------
  pub rsa3072 2020-03-26 [SC]
    XXXXXXXXXXXXX-FINGERPRINT-XXXXXXXXXXXXXX
  uid 		[ultimate] backups (Scaleway Object Storage backups) <me@scaleway.com>
  sub rsa3072 2020-03-26 [E]

Tip

If you lose access to your current server, having the GPG private and public keys stored somewhere else will come in handy. Export the GPG keys with:

gpg --armor --export backups
gpg --armor --export-secret-key backups

Combining Duplicity and ScalewayLink to this anchor

As everything is installed and ready, we will now configure and script our interactions between our server and the cloud.

Editing the configurationLink to this anchor

Create our initial, empty script files and log files and make them executable.

    touch scw-backups.sh scw-restore.sh .scw-configrc
    chmod 700 scw-backups.sh scw-restore.sh
    chmod 600 .scw-configrc
    mkdir -p /var/log/duplicity
    touch /var/log/duplicity/logfile{.log,-recent.log}

Create a config file ~/.scw-backup.env. Make sure you replace the necessary values with the details of your Scaleway API key, Object Storage bucket, and GPG key. You also need to enter a path to the folder you want to back up:

# Scaleway credentials keys
export AWS_ACCESS_KEY_ID="<SCALEWAY ACCESS KEY>"
export AWS_SECRET_ACCESS_KEY="<SCALEWAY SECRET KEY>"
export SCW_REGION="<REGION OF YOUR BUCKET>s"
export SCW_ENDPOINT_URL="https://s3.${SCW_REGION}.scw.cloud"
export SCW_BUCKET="s3://<YOUR BUCKET NAME>"
# GPG Key information
export GPG_FINGERPRINT="<YOUR GPG KEY FINGERPRINT>"
export PASSPHRASE="<YOUR GPG KEY PASSPHRASE>"
# Folder to backup
export SOURCE="/path/to/backup"
# Will keep backup up to 1 month
export KEEP_BACKUP_TIME="1M"
# Will make a full backup every 10 days
export FULL_BACKUP_TIME="10D"
# Log files
export LOGFILE_RECENT="/var/log/duplicity/logfile-recent.log"
export LOGFILE="/var/log/duplicity/logfile.log"

The backup policy described here makes a full backup every 10 days and removes all backups older than one month.

Backup scriptLink to this anchor

Using the configuration and Duplicity, we automatize the backup process with the scw-backups.sh script.

Copy the following script to scw-backups.sh:

#!/bin/bash
source ~/.scw-backup.env
mkdir -p /var/log/duplicity
touch "$LOGFILE_RECENT" "$LOGFILE"
currently_backuping=$(pgrep -f duplicity | wc -l)
if [ "$currently_backuping" -eq 0 ]; then
  echo "$(date '+%F %T') >>> Removing old backups" >> "$LOGFILE_RECENT"
  duplicity remove-older-than "$KEEP_BACKUP_TIME" "$SCW_BUCKET" \
    --s3-endpoint-url "$SCW_ENDPOINT_URL" \
    --s3-region-name "$SCW_REGION" >> "$LOGFILE_RECENT" 2>&1
  echo "$(date '+%F %T') >>> Running backup" >> "$LOGFILE_RECENT"
  duplicity \
    incr --full-if-older-than "$FULL_BACKUP_TIME" \
    --asynchronous-upload \
    --encrypt-key="$GPG_FINGERPRINT" \
    --sign-key="$GPG_FINGERPRINT" \
    --s3-endpoint-url "$SCW_ENDPOINT_URL" \
    --s3-region-name "$SCW_REGION" \
    "$SOURCE" "$SCW_BUCKET" >> "$LOGFILE_RECENT" 2>&1
  cat "$LOGFILE_RECENT" >> "$LOGFILE"
fi

Make the script executable:

chmod +x ~/scw-backup.sh

Run the script ./scw-backups.sh to make sure the configuration is correctly set. Check the Object Storage bucket on the Scaleway console to see the backup files, or examine the logs with the following command:
```
cat /var/log/duplicity/logfile-recent.log
```

Script the recovery of dataLink to this anchor

Duplicity also allows you to recover a backup. We will create a script to make the process easier.

Add the following script to scw-restore.sh:

#!/bin/bash
source ~/.scw-backup.env
if [ $# -lt 2 ]; then
  echo "Usage: $0 <time or delta> [file to restore] <restore dir>"
  exit 1
fi
if [ $# -eq 2 ]; then
  duplicity \
    --s3-endpoint-url "$SCW_ENDPOINT_URL" \
    --s3-region-name "$SCW_REGION" \
    --time "$1" \
    "$SCW_BUCKET" "$2"
elif [ $# -eq 3 ]; then
  duplicity \
    --s3-endpoint-url "$SCW_ENDPOINT_URL" \
    --s3-region-name "$SCW_REGION" \
    --time "$1" \
    --file-to-restore "$2" \
    "$SCW_BUCKET" "$3"
fi

Make the script executable:

chmod +x ~/scw-restore.sh

Automation of the backupsLink to this anchor

Use the command crontab -e to edit your crontab file and add the line to create a script that will run twice a day at 1:00 and 13:00 (1 AM and 1 PM):

    crontab -e

Select your editor and write:

    PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
    SHELL=/bin/bash
    00 1,13 * * * <FULL PATH TO>/scw-backups.sh > /dev/null 2>&1

ConclusionLink to this anchor

We created an automatic backup using Duplicity, hosting the encrypted data on Scaleway’s Object Storage. We are able to recover specific files or the entire backup itself at a given date.

To continue your implementation, you may want to consider the following:

Duply, giving you a front-end view of the backups.
Backing up more than one folder using “SOURCE=/” and the --include= and --exclude= options of duplicity.
Adapt the backup policy with more frequent backups, that are conserved.

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