Dockcheck

Dockcheck is a Bash-based CLI utility for checking whether your running Docker containers have newer images available, and optionally updating them. It supports both interactive selection and unattended automation, with a focus on efficient registry checks without pre-pulling images.

Key Features

• Interactive or unattended update runs, including selective include/exclude of containers
• Checks for available image updates without pre-pulling images (helps minimize unnecessary pulls)
• Optional image backup before updating for easier rollback, with retention by days
• Notification system with multiple pluggable channels (for update availability and runs)
• Label-based targeting to only act on explicitly marked containers
• Optional auto-prune of dangling images after updates
• Prometheus textfile export for node_exporter (metrics output)
• Supports timeouts and concurrent/asynchronous checks for faster runs

Use Cases

• Automate routine Docker image update checks on a homelab server and get notified only when changes occur
• Selectively update only a subset of containers while excluding critical workloads
• Create simple rollback safety by backing up images before pulling new versions

Limitations and Considerations

• Designed for Docker workflows; while it can check updates for some docker run containers, it won’t automatically update those containers
• Some functionality relies on external tools such as jq and regctl, and regctl availability may be limited on certain CPU architectures

Dockcheck is a practical fit for operators who want a lightweight, scriptable approach to container update checks, with optional automation and notifications. It is especially useful where you want control over what gets updated and when, without adopting a heavier management platform.