Docker Compose Drift Detector

Docker Compose Drift Detector Skill

Stateless atomic operation to query Docker containers/Swarm services, retrieve active running configurations, parse reference Compose/YAML template repositories, and perform automated drift detection of images, environments, and mounts.

Prerequisites

• container-manager-mcp — for inspecting active containers, query image manifests, list service definitions, and inspect active cluster configurations.

Steps

Step 1: retrieve_active_topology

Fetch real-time execution telemetry and configuration parameters from running containers:

• Query active container landscape:
  • Fetch list of running containers or Swarm services via container-manager-mcp (e.g., using list_containers action).
  • Filter target containers by namespace, stack name, or specific project identifier.
• Inspect detailed configuration properties:
  • Query specific properties of each targeted container or service (image name, image tag, exact registry digest hash, active environment variables, volume mount mappings, network attachments, and replica counts).
• Output parameters:
  • active_containers: Mapping of container names to their active running state configuration objects.

Step 2: diff_configurations [depends_on: retrieve_active_topology]

Locate and parse target Compose template files and execute differential comparison analysis:

• Locate configuration templates:
  • Scan repository folders or target workspace paths for compose files (e.g., docker-compose.yml, caddy-compose.yml, stack templates).
• Parse and resolve templates:
  • Read target reference compose files.
  • Substitute environment variables and .env properties to resolve template values as they would be generated in deployment.
• Granular differential review:
  • Perform element-by-element comparison between the running container configuration and the resolved reference compose file.
  • Compare target fields:
    • Image/Tag: Verify if the running tag/digest matches the reference specification.
    • Environment Overrides: Compare key-value pairs of active environment variables.
    • Mount Configuration: Ensure host paths and container mount points are synchronized.
    • Replicas/Scale: Check if active counts match template directives.
• Output parameters:
  • drift_detected: Boolean indicating if any differences were discovered.
  • drift_matrix: Object mapping each mismatched attribute to its template and running value.

Step 3: report_drift_status [depends_on: diff_configurations]

Categorize drift severity and format telemetry reports:

• Classify drift types:
  • IMAGE_DRIFT: Indicates container is running an out-of-date image or a different tag compared to the git repository.
  • ENV_DRIFT: Indicates missing or mismatched environment configuration keys.
  • SCALE_DRIFT: Indicates replica or service sizing mismatch.
• Compile summary payload:
  • Synthesize a comprehensive JSON and Markdown representation of the configuration differences.
• Output parameters:
  • status: "SUCCESS" or "FAILED"
  • drift_summary: Markdown summary of detected variations.
  • severity: String indicating action priority ("NONE", "LOW", "MEDIUM", "HIGH").