Docker Data Backup

Overview

This role performs comprehensive backup of Docker data volumes to dual NAS storage. It intelligently orchestrates the backup process by scheduling Centreon monitoring downtimes, gracefully stopping containers, creating compressed archives, and automatically managing retention. This ensures data consistency while minimizing false monitoring alerts.

What This Role Does

Phase 1: Downtime Scheduling

1. Calculates downtime window based on current time and duration
2. Schedules Centreon downtimes for three services:
   • Docker Containers Uptime (container uptime check)
   • Docker Containers Status (container health check)
   • Check Nginx Proxy Port (reverse proxy availability)
3. Delegates to Centreon server using CLAPI commands

Phase 2: Backup Execution

1. Ensures backup directories exist on both NAS mount points
2. Stops all Docker containers using Docker Compose V2 (docker compose down)
3. Waits 10 seconds for containers to fully stop
4. Creates compressed tar.gz archive of entire Docker data directory
5. Copies archive to both NAS devices with timestamp in filename
6. Starts all Docker containers using Docker Compose V2 (docker compose up)

Phase 3: Cleanup

1. Finds all existing backups on each NAS
2. Removes old backups, keeping only the 2 most recent per NAS

Role Variables

Variable	Description
vault_centreon_admin_password	Centreon admin password (from vault)
centreon_host_name	Host name as it appears in Centreon (from host_vars)
docker_compose_directory	Directory containing compose.yaml (from host_vars)
docker_data_path	Directory containing all Docker volume data (from host_vars)
docker_data_backup_syno_mount_point	Synology NAS backup destination
docker_data_backup_prxmxomv_mount_point	Proxmox OMV NAS backup destination
docker_data_backup_downtime_duration_minutes	Centreon downtime window duration
docker_data_backup_nases_path	List of timestamped destination file paths

Backup filenames: docker_data_backup_YYYYMMDDTHHMMSS.tar.gz

Notes

• Containers are stopped during the backup — services will be briefly unavailable
• Centreon downtime is scheduled for: Docker Containers Uptime, Docker Containers Status, Check Nginx Proxy Port
• Centreon downtime failures use failed_when: false — backup proceeds even if Centreon is unreachable
• Keeps last 2 backups per NAS (unlike most other backup roles which keep 5)
• After backup, containers are always restarted even if archiving fails
• Use docker_data_restore role to restore from a backup