Docker Volume Backup Script

Overview

This script automates the process of backing up Docker volumes (named volumes, bind mounts, and anonymous volumes) for containers managed by a docker-compose.yml file. It supports error handling, dependency checks, and notification via ntfy for failures or significant events.

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Features

• Supports All Volume Types:
  • Named Volumes
  • Bind Mounts
  • Anonymous Volumes
• Error Handling:
  • Sends notifications on errors via ntfy.
• Dependency Check:
  • Ensures required tools (docker, jq, tar, curl) are installed.
• Automatic Backup Directory Creation:
  • Stores backups in timestamped directories for organization.
• Container-Level Processing:
  • Automatically identifies and processes volumes attached to containers.

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Requirements

• Dependencies:
  • docker
  • jq
  • tar
  • curl
• ntfy Configuration:
  • Replace NTFY_TOPIC and NTFY_SERVER in the script with your ntfy topic and server.

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Installation

1. Save the script to a file, e.g., backup_docker_volumes.sh.
2. Make it executable:

   chmod +x backup_docker_volumes.sh
   

3. Install dependencies if not already installed:

   sudo apt-get install docker jq tar curl
   

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Usage

Run the script with the path to a docker-compose.yml file:

./backup_docker_volumes.sh /path/to/docker-compose.yml

Example Output

• Backup Directory: Backups are stored in a directory named backup_<DATE>_<TIME>, created in the current working directory.

• Notifications:

  • Successful completions send a "Backup Complete" notification.
  • Errors send "Backup Error" notifications.

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Script Details

Functions

1. Dependency Check

   • check_command: Verifies if a command is available on the system.
   • check_dependency: Checks all dependencies before execution.

2. Notification System

   • send_notification: Sends notifications via ntfy for errors or events.

3. Backup Operations

   • backup_named_volume: Backs up Docker named volumes.
   • backup_bind_mount: Backs up bind-mounted directories.
   • backup_anonymous_volume: Backs up anonymous volumes.

4. Container Volume Processing

   • backup_volumes_for_service: Processes all volumes for a specific container.
   • backup_docker_compose_volumes: Processes all containers defined in the docker-compose.yml.

5. Utility

   • create_backup_dir: Creates a timestamped backup directory.

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Notifications

ntfy Integration

This script uses ntfy to send notifications. Update the following variables in the script to configure ntfy:

• NTFY_TOPIC: The topic for the ntfy server (e.g., "backup-alerts").
• NTFY_SERVER: The ntfy server URL (default: https://ntfy.sh).

Example Notifications

• Backup Success:
  • Title: Backup Complete
  • Message: Backup successfully completed for all services in <docker-compose.yml>.
• Backup Error:
  • Title: Backup Error
  • Message: Details of the failed backup.

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Known Limitations

1. Docker Volumes Only:
   • The script does not handle other container data (e.g., logs or ephemeral filesystems).
2. ntfy Dependency:
   • Requires an active ntfy server and internet access for notifications.
3. jq Parsing:
   • Assumes consistent Docker JSON structure; unexpected changes might cause parsing issues.

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Troubleshooting

Common Errors

1. Missing Dependencies:

   • Error: "Error: <dependency> is not installed."
   • Solution: Install the missing dependency using your package manager.

2. ntfy Notifications Fail:

   • Error: "Failed to send notification via ntfy."
   • Solution: Verify curl installation and ntfy server configuration.

3. Permission Issues:

   • Error: "Permission denied"
   • Solution: Ensure the script has executable permissions and proper access to Docker volumes.

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License

This project is licensed under the AGPL-3.0 License. See the LICENSE file for details.