Watchtower vs DIUN: Docker Update Tools

Quick Verdict

DIUN is the safer choice for most self-hosters. It notifies you when updates are available without touching your running containers, giving you full control over when and how you update. Watchtower is for people who want fully automatic updates and accept the risk that an unattended update could break a service.

Overview

Watchtower monitors your running Docker containers and automatically updates them when a new image is pushed to the registry. It pulls the new image, stops the old container, and restarts it with the same configuration. There is no web UI — it runs as a background daemon.

DIUN (Docker Image Update Notifier) monitors Docker images for updates and sends notifications through your preferred channel (Discord, Slack, Telegram, email, webhooks, and 15+ more). It never pulls images or restarts containers. You get notified, you decide what to do.

These tools have fundamentally different philosophies. Watchtower automates the entire update lifecycle. DIUN automates only the detection and notification. The question is whether you trust unattended updates.

Feature Comparison

Feature	Watchtower	DIUN
Update detection	Yes — checks registries on schedule	Yes — checks registries on schedule
Automatic container updates	Yes — pull, stop, restart	No — notification only
Notification channels	Email, Slack, MS Teams, Gotify, Shoutrrr	15+ channels: Discord, Slack, Telegram, email, Matrix, Gotify, Ntfy, webhooks, and more
Label-based filtering	Yes — include/exclude by label	Yes — include/exclude by label
Per-container control	Yes — enable/disable updates per container	Yes — monitor specific containers
Private registry support	Yes	Yes
Schedule/cron support	Yes — cron syntax	Yes — cron syntax
Monitor non-running images	No — only running containers	Yes — can watch any image tag
Multi-platform image support	Basic	Yes — tracks multiple architectures
Digest-based tracking	Yes	Yes — tracks manifests and digests
Metadata in notifications	Basic — container name, old/new image	Rich — image name, tag, digest, platform, link to registry
Cleanup old images	Yes — --cleanup flag	No (not its job)
Rolling restart	No — stop then start	N/A
Run once mode	Yes — --run-once flag	Yes — --test-notif for testing
Web UI	No	No
License	Apache 2.0	MIT

Installation Complexity

Both are single-container deployments with Docker socket access. Installation is equally simple.

Watchtower needs only the Docker socket mount and optional environment variables for notifications and scheduling. Minimal config — it works with zero env vars (default: check every 24 hours, update everything).

DIUN requires a config file or environment variables to set up notification providers. The initial setup is slightly more involved because you need to configure at least one notification channel, but the config format is straightforward YAML.

Performance and Resource Usage

Metric	Watchtower	DIUN
Idle RAM	~15-25 MB	~20-30 MB
During check	~30-50 MB	~30-50 MB
CPU usage	Minimal (spikes during checks)	Minimal (spikes during checks)
Docker image size	~15 MB	~20 MB

Both are extremely lightweight. Resource usage is negligible on any system. Neither has a web UI, so there is no frontend overhead.

Community and Support

Metric	Watchtower	DIUN
GitHub stars	19K+	3K+
First release	2015	2019
Maintainer	containrrr team	crazy-max (single, very active)
Release cadence	Regular	Regular
Documentation	Good README + docs site	Excellent — detailed docs site

Watchtower has higher name recognition and more stars, but DIUN’s documentation is better organized and covers more edge cases. Both are actively maintained as of 2026.

Use Cases

Choose Watchtower If…

• You want fully automatic, hands-off container updates
• You run non-critical services where brief downtime during updates is acceptable
• You pin image tags and use Watchtower only for patch updates within a tag
• You want the simplest possible “set and forget” update solution
• You are comfortable with the risk of an update breaking a service while you are away

Choose DIUN If…

• You want to control exactly when updates happen
• You run services where unexpected restarts cause data loss (databases, media servers mid-transcode)
• You want rich notifications with update details before deciding to update
• You need to monitor images that are not currently running
• You run production or semi-production workloads
• You use a notification platform (Discord, Telegram, Ntfy) and want update alerts in your existing workflow

FAQ

Can I use both together?

Yes, but it is redundant. If you use Watchtower for auto-updates, you already know updates are happening. If you want notification before automatic updates, configure Watchtower’s built-in notifications. Using DIUN alongside Watchtower adds no value.

Is Watchtower dangerous?

It can be. Automatic updates can break your services — a new image might have breaking changes, bugs, or incompatible config. Watchtower has no rollback mechanism. If an update breaks something, you need to manually pull the old image and redeploy. This is why many experienced self-hosters prefer DIUN’s notify-only approach.

Can Watchtower be set to monitor-only mode?

Yes — use the --monitor-only flag. In this mode, Watchtower checks for updates and sends notifications but does not pull or restart containers. This effectively makes it behave like DIUN, though DIUN has better notification options.

What about Ouroboros as an alternative?

Ouroboros was a similar auto-update tool but has been abandoned. Use Watchtower or DIUN instead.

Final Verdict

DIUN is the better tool for most self-hosters. Automatic updates sound convenient, but unattended container restarts are a real risk — especially for stateful services like databases, media servers, and file sync tools. DIUN gives you awareness without risk. You see the update, you read the changelog, you update when ready.

Use Watchtower only if you are fully committed to automatic updates and accept the tradeoffs. Even then, use label filtering to exclude critical services from auto-updates and only let Watchtower manage low-risk containers.

Related

• How to Self-Host Watchtower with Docker
• How to Self-Host DIUN with Docker
• How to Self-Host Portainer with Docker
• Best Docker Management Tools
• Docker Compose Basics
• Backup Strategy (3-2-1 Rule)