This is a straightforward script designed to automate Duplicity for backing up Docker volumes to an external hard drive. It includes a detailed log file for backup information and automatically deletes backups older than 20 days to manage storage efficiently.

gistfile1.txt

#!/bin/bash

# Define backup destination (replace with your external drive path)
BACKUP_DEST="/path/to/backup_drive"

LOG_FILE="/path/to/backup.log"

# Clear log file
echo "Starting backup process at $(date)" > "$LOG_FILE"
echo "" >> "$LOG_FILE"

export PASSPHRASE="" # add GnuPG passphrase

# List of Docker volumes to back up
VOLUMES=("" "") # Add docker volume names here (as many as you want in seperate "")

for volume in "${VOLUMES[@]}"
do
    echo "Backing up volume $volume..."
    echo "$(date) - Backing up volume $volume..." >> "$LOG_FILE"

    # Check if Docker volume exists and can be inspected
    if docker volume inspect "$volume" >/dev/null 2>&1; then
        echo "$(date) - Performing full backup for $volume." >> "$LOG_FILE"
        # Perform full backup
        duplicity full /var/lib/docker/volumes/"$volume"/_data file://"$BACKUP_DEST/$volume" >> "$LOG_FILE" 2>&1
        if [ $? -eq 0 ]; then
            echo "$(date) - Full backup of volume $volume completed successfully." >> "$LOG_FILE"
        else
            echo "$(date) - Full backup of volume $volume failed." >> "$LOG_FILE"
        fi

        # Delete backups older than 20 days
        duplicity remove-all-but-n-full 20 --force "$BACKUP_DEST/$volume" >> "$LOG_FILE" 2>&1
        if [ $? -eq 0 ]; then
            echo "$(date) - Deleted old backups for volume $volume successfully." >> "$LOG_FILE"
        else
            echo "$(date) - Failed to delete old backups for volume $volume." >> "$LOG_FILE"
        fi
    else
        echo "$(date) - Volume $volume does not exist or cannot be inspected." >> "$LOG_FILE"
        echo "Volume $volume does not exist or cannot be inspected."
    fi
done
unset PASSPHRASE