Diun vs Cosmos Cloud: Compared
Quick Verdict
These solve different problems at different scales. Cosmos Cloud is a full self-hosting platform with container management, reverse proxy, and auto-updates. Diun is a lightweight notification service that tells you when container image updates are available. If you use Cosmos Cloud, you probably don’t need Diun. If you use Portainer or Dockge for management, Diun adds valuable update awareness.
Overview
Cosmos Cloud is an all-in-one self-hosting platform combining Docker management, reverse proxy with SSL, app marketplace, VPN integration, security features, and automatic container updates. Current version: v0.20.2.
Diun (Docker Image Update Notifier) is a single-purpose tool that monitors Docker registries for new image versions and sends notifications via 20+ providers (Discord, email, Slack, Gotify, etc.). It does not apply updates — notify only. Current version: 4.31.0.
Feature Comparison
| Feature | Cosmos Cloud v0.20 | Diun 4.31 |
|---|---|---|
| Container management | Yes (full GUI) | No |
| Reverse proxy | Yes (built-in) | No |
| App marketplace | Yes | No |
| Update detection | Yes | Yes |
| Update notifications | Via platform | Yes (20+ providers) |
| Automatic update application | Yes | No (notify only) |
| Per-container monitoring | Yes | Yes (via labels) |
| Custom schedule | Yes | Yes (cron) |
| Registry support | Docker Hub | Docker Hub, GHCR, ACR, ECR, GCR, etc. |
| RAM usage | ~150-200 MB | ~15-20 MB |
| Purpose | Full platform | Single-purpose notifier |
Use Cases
Choose Cosmos Cloud If…
- You want one platform for management, proxy, and updates
- You want automatic update application (not just notifications)
- You’re setting up a new self-hosting environment
- You want an app marketplace and user management
Choose Diun If…
- You already have a management stack (Portainer, Dockge, etc.)
- You prefer to be notified but decide when to update manually
- You want notifications in specific channels (Discord, Slack, Gotify)
- You need lightweight resource usage (~15 MB vs ~200 MB)
- You monitor images across multiple registries (GHCR, ECR, etc.)
Final Verdict
Cosmos Cloud replaces the need for Diun by including update management built-in. If you’re already invested in Cosmos Cloud, adding Diun is redundant.
Diun’s value is in setups where you use separate tools for management and proxying. Diun fills the “update awareness” gap that Portainer and Dockge don’t cover natively. Its notify-only approach is also safer than automatic updates — you stay in control of when updates happen. (Watchtower, which offered auto-updates, is now deprecated.)
Frequently Asked Questions
Does Cosmos Cloud notify about updates like Diun?
Cosmos Cloud shows available updates in its UI but doesn’t have Diun’s 20+ notification provider integrations. If you need Discord/Slack/Gotify notifications specifically, Diun is more flexible for notification delivery.
Can Diun trigger Cosmos Cloud to update?
Not directly. Diun is notify-only — it doesn’t integrate with container management tools to trigger updates. You’d need to apply updates manually through Cosmos Cloud’s UI after Diun notifies you.
Which uses less resources?
Diun by a wide margin (~15 MB vs ~200 MB). But that’s an unfair comparison — Cosmos Cloud does 10x more things than Diun.
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