Cleanup Docker Resources

Description

This role performs a complete cleanup of Docker resources by invoking a systemd-managed script. It removes unused Docker images, stopped containers, networks, build cache, and anonymous volumes. The cleanup is fully automated and can run on a schedule or be triggered manually.

Overview

Optimized for maintaining a clean and efficient Docker environment, this role:

  • Loads and triggers the anonymous volume cleanup role.

  • Installs a systemd service and timer for Docker pruning.

  • Deploys a cleanup script that invokes:

    • The anonymous volume cleanup service.

    • docker system prune -a -f to remove unused Docker resources.

  • Allows forced execution during maintenance runs (MODE_CLEANUP).

Purpose

The primary purpose of this role is to prevent storage bloat caused by unused Docker images, volumes, and build artifacts. Regular pruning ensures:

  • Reduced disk usage

  • Improved system performance

  • Faster CI/CD and container deployments

  • More predictable Docker engine behavior

Features

  • Anonymous Volume Cleanup: Integrates with sys-ctl-cln-anon-volumes to remove stale volumes.

  • Full Docker Prune: Executes docker system prune -a -f to reclaim space.

  • Systemd Integration: Registers a systemd unit and timer for automated cleanup.

  • Scheduled Execution: Runs daily (or as configured) based on SYS_SCHEDULE_CLEANUP_DOCKER.

  • Force Execution Mode: When MODE_CLEANUP=true, cleanup is executed immediately.

  • Safe Execution: Includes validation for missing services and Docker availability.

Script Behavior

The cleanup script:

  1. Checks whether the anonymous volume cleanup service is defined and available.

  2. Starts the service if present.

  3. Runs docker system prune -a -f if Docker is installed.

  4. Stops execution immediately on errors (set -e behavior).