Watchtower vs Cosmos Cloud: Compared
⚠️ Watchtower is deprecated. The
containrrr/watchtowerrepository is archived and no longer maintained. Consider DIUN or What’s Up Docker as actively maintained alternatives. This comparison remains available for reference.
Quick Verdict
These are very different tools. Cosmos Cloud is a full self-hosting platform (container management + reverse proxy + app store + security). Watchtower is a single-purpose tool that automatically updates running containers to their latest image versions. Cosmos Cloud has built-in auto-update functionality, making Watchtower redundant if you use Cosmos Cloud.
Overview
Cosmos Cloud combines Docker management, a built-in reverse proxy with SSL, an app marketplace, VPN integration, user authentication, and automatic container updates in a single platform. Current version: v0.20.2.
Watchtower does one thing: it monitors running containers for image updates, pulls new versions, and recreates containers automatically. No UI, no proxy, no management — just automated updates. Current version: v1.7.1 (note: last release November 2023, maintenance mode).
Feature Comparison
| Feature | Cosmos Cloud v0.20 | Watchtower v1.7.1 |
|---|---|---|
| Container management | Yes (full GUI) | No |
| Built-in reverse proxy | Yes (with SSL) | No |
| App marketplace | Yes | No |
| Auto-update containers | Yes | Yes |
| Update notifications | Yes | Yes (email, Slack, etc.) |
| Per-container update control | Yes | Yes (labels) |
| Schedule updates | Yes | Yes (cron expression) |
| Old image cleanup | Yes | Yes |
| User management | Yes (multi-user, 2FA) | No |
| VPN integration | Yes (Constellation) | No |
| DDoS protection | Yes (Smart Shield) | No |
| Resource monitoring | Yes | No |
| RAM usage | ~150-200 MB | ~15-20 MB |
| Active development | Yes (2026) | No (last release Nov 2023) |
When Watchtower Still Makes Sense
If you’re already using Portainer or Dockge for container management and Nginx Proxy Manager or Traefik for proxying, adding Watchtower for auto-updates is a lightweight, focused solution. It doesn’t replace any of those tools — it adds one capability they lack.
If you’re using Cosmos Cloud, Watchtower is redundant. Cosmos handles updates natively.
Use Cases
Choose Cosmos Cloud If…
- You want an all-in-one platform (management + proxy + updates)
- You’re starting from scratch and want one tool for everything
- You want built-in security features (Smart Shield, VPN)
- You want an app marketplace for one-click deployments
- You want active development and regular updates
Choose Watchtower If…
- You already have a container management and proxy setup
- You want a minimal, single-purpose update automation tool
- You want to add auto-updates without changing your existing stack
- You need fine-grained update scheduling and notification options
Final Verdict
Cosmos Cloud if starting fresh, Watchtower if adding to existing setup. Cosmos Cloud makes Watchtower redundant by including auto-updates as part of a larger platform. But if you already run Portainer + Traefik (or similar) and just want automated container updates, Watchtower is a 20 MB addition that does exactly that.
Note: Watchtower hasn’t had a release since November 2023. For a notify-only alternative (tells you about updates without auto-applying), consider Diun which is actively maintained.
Frequently Asked Questions
Does Cosmos Cloud auto-update like Watchtower?
Yes. Cosmos Cloud can automatically check for and apply container updates. The functionality overlaps with Watchtower’s core feature.
Can I run Watchtower alongside Cosmos Cloud?
Technically yes, but it’s redundant. They’d both try to update the same containers, potentially causing conflicts. Use one or the other for auto-updates.
Is Watchtower still safe to use given it’s in maintenance mode?
Yes, for now. The current version works correctly. The risk is that future Docker API changes could break compatibility with no fix coming. For critical setups, consider Diun (notify-only) plus manual updates.
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