Jonathan Lalou's Blog

TL;DR:
To back up all your Docker images safely, use docker save to export them and gzip to compress them.
Then, when you need to restore, use docker load to re-import everything.
Below you’ll find production-ready Bash scripts for automated backup and restore — complete with compression and error handling.

📦 Why You Need This

Whether you’re upgrading your system, cleaning your Docker environment, or migrating to another host, exporting your local images is crucial. Docker’s built-in commands make this possible, but using them manually for dozens of images can be tedious and space-inefficient.
This article provides automated scripts that will:

• Backup every Docker image individually,
• Compress each file with gzip for storage efficiency,
• Restore all images automatically with a single command.

🧱 Backup Script (backup_docker_images.sh)

The script below exports all Docker images, one by one, into compressed .tar.gz files.
Each image gets its own archive, named after its repository and tag.

#!/bin/bash
# --------------------------------------------
# Backup all Docker images into compressed .tar.gz files
# --------------------------------------------

BACKUP_DIR=~/docker-backup
mkdir -p "$BACKUP_DIR"
cd "$BACKUP_DIR" || exit 1

echo "📦 Starting Docker image backup..."
echo "Backup directory: $BACKUP_DIR"
echo

for image in $(docker image ls --format "{{.Repository}}:{{.Tag}}"); do
  # sanitize file name
  safe_name=$(echo "$image" | tr '/:' '__')
  outfile="${safe_name}.tar"
  gzfile="${outfile}.gz"

  echo "🟢 Saving $image → $gzfile"

  # Save and compress directly (no uncompressed tar left behind)
  docker save "$image" | gzip -c > "$gzfile"

  if [ $? -eq 0 ]; then
    echo "✅ Successfully saved $image"
  else
    echo "❌ Error saving $image"
  fi
  echo
done

echo "🎉 Backup complete!"
ls -lh "$BACKUP_DIR"/*.gz

💡 What This Script Does

• Creates a ~/docker-backup directory automatically.
• Iterates over every local Docker image.
• Uses docker save piped to gzip for direct compression.
• Prints friendly success and error messages.

Result: You’ll get a set of compressed files like:

jonathan-tomcat__latest.tar.gz
jonathan-mysql__latest.tar.gz
jonathan-grafana__latest.tar.gz
...

🔁 Restore Script (restore_docker_images.sh)

This companion script automatically restores every compressed image. It detects both .tar.gz and .tar files in the backup directory, decompresses them, and loads them back into Docker.

#!/bin/bash
# --------------------------------------------
# Restore all Docker images from .tar.gz or .tar files
# --------------------------------------------

BACKUP_DIR=~/docker-backup
cd "$BACKUP_DIR" || { echo "❌ Backup directory not found: $BACKUP_DIR"; exit 1; }

echo "🚀 Starting Docker image restore from $BACKUP_DIR"
echo

for file in *.tar.gz *.tar; do
  [ -e "$file" ] || { echo "No backup files found."; exit 0; }

  echo "🟡 Loading $file..."
  if [[ "$file" == *.gz ]]; then
    gunzip -c "$file" | docker load
  else
    docker load -i "$file"
  fi

  if [ $? -eq 0 ]; then
    echo "✅ Successfully loaded $file"
  else
    echo "❌ Error loading $file"
  fi
  echo
done

echo "🎉 Restore complete!"
docker image ls

💡 How It Works

• Automatically detects .tar.gz or .tar backups.
• Decompresses each one and loads it into Docker.
• Prints progress updates as it restores each image.

After running it, your local Docker environment will look exactly like before — same repositories, tags, and image IDs.

⚙️ How to Use

1️⃣ Backup All Docker Images

chmod +x backup_docker_images.sh
./backup_docker_images.sh

You’ll see a live summary of each image as it’s saved and compressed.

2️⃣ Restore Later (After a Prune or Reinstall)

chmod +x restore_docker_images.sh
./restore_docker_images.sh

Docker will reload each image automatically, maintaining all original metadata.

💾 Bonus: Cleaning and Rebuilding Your Docker Environment

If you want to clear all Docker data before restoring your images, run:

docker system prune -a --volumes

⚠️ Warning: This deletes all containers, images, networks, and volumes.
Afterward, simply run the restore script to bring your images back.

🧠 Why Use Gzip?

Docker image archives are often large — several gigabytes each. Compressing them with gzip:

• Saves 30–70% of disk space,
• Speeds up transfers (especially over SSH),
• Keeps the backups cleaner and easier to manage.

You can still restore them directly with gunzip -c file.tar.gz | docker load — no decompression step required.

✅ Summary Table

🚀 Conclusion

Backing up your Docker images is a crucial part of any development or CI/CD workflow. With these two scripts, you can protect your local Docker environment from accidental loss, disk cleanup, or reinstallation.
By combining docker save and gzip, you ensure both efficiency and recoverability — making your Docker workstation fully portable and disaster-proof.

Keep calm and backup your containers 🐳💾