Had a discussion with AI about all these issues and wanted to summarise everything so is easily understandable for all of us running in to problems.
Important Notice: Docker 29.x Issues Affecting Traefik, Redis & MySQL
Summary for community users
Several users have reported service failures after upgrading Docker Engine to 29.0.0 or 29.1.1.
These issues affect Traefik, Redis, MySQL, and other services that previously worked fine under Docker 28.2.2.
Below is a full explanation of what’s happening, why it’s happening, and how to fix it.
What’s Going Wrong in Docker 29.x?
Docker 29 introduced two major changes:
A breaking Docker API change
Starting in Docker 29, Docker now requires API version 1.44 or newer.
Many tools still use older API versions, including:
- Traefik
- Portainer
- Watchtower
- Some CI/CD deployers
- Older Docker Compose versions
- Various Docker automation scripts
Because of this, these tools can no longer communicate properly with the Docker daemon.
This leads to:
- Traefik failing to detect containers
- Routes not updating after redeploy
- Reverse proxy responses returning 404 errors
- Services failing to register on networks
- Deployment tools silently failing
Traefik is especially impacted because it relies heavily on the Docker API for service discovery.
Networking and DNS regressions
Docker 29.0.0 introduced DNS and network instability.
Docker 29.1.1 fixed some of the DNS issues — but not all of them.
Remaining issues include:
- Containers losing DNS after redeploy
- Services unable to resolve each other by name
- Overlay networks disconnecting
- Health checks failing intermittently
- Network attachments not applied during updates
These networking issues affect Redis and MySQL even though they do not use the Docker API.
How Each Service Is Affected
Traefik (most severely affected)
Traefik relies on the Docker API to discover containers and routes.
Under Docker 29.x:
- API queries fail (client too old)
- Traefik cannot track new containers
- Routes disappear after redeploy
- Reverse proxy returns 404 Not Found even when containers are healthy
This is why users experience complete outages after updating or redeploying services.
Redis
Redis itself is fine — the database has no dependency on Docker's API changes.
But Redis appears to break because:
- DNS between containers becomes unstable
- Apps cannot resolve the Redis hostname
- Network updates during redeploy aren’t applied
- Health checks fail, causing Redis to restart unnecessarily
Typical symptoms:
- “Cannot connect to Redis”
- Connection refused
- Host not found
Rolling back Docker fixes all of these immediately.
MySQL
Same story as Redis — MySQL itself isn’t incompatible.
But Docker’s regression causes:
- containers unable to find
mysqlby name - applications failing to connect after redeploy
- MySQL container being reattached to wrong network
- volume or mount inconsistencies after engine update
- intermittent “connection lost” errors
Users often mistake this for MySQL failure — it’s actually Docker networking.
Why Everything Works Again on Docker 28.2.2
Docker 28.2.2:
- supports older API versions
- provides stable networking and DNS
- does not break Traefik’s container discovery
- handles redeployments consistently
- maintains known-good behavior for Compose & Swarm
This is why rolling back instantly resolves Traefik, Redis, and MySQL issues.
Recommended Resolution
1. Do NOT use Docker 29.x for now
For all systems running Traefik, Redis, MySQL, or any interconnected services:
Stay on Docker Engine 28.2.2
Pin the version to prevent future upgrades
This is currently the safest and most stable version.
2. If you must use Docker 29.x
Isolate services that rely on older API versions:
- run Traefik (and/or Redis/MySQL) on a separate host,
- or inside a Docker-in-Docker (dinD) instance using Docker 28.x,
- or keep them on a dedicated node in a multi-node environment.
This prevents global breakage.
3. Wait for Traefik and others to release API-1.44 compatible updates
Once Traefik and other tools update their Docker API clients, Docker 29 will become usable again.
Until then, upgrading the engine will continue to break deployments.
Final Summary
| Component | Broken in Docker 29.x? | Why | Fixed by Downgrading to 28.2.2? |
|---|---|---|---|
| Traefik | Yes |
API version mismatch (client too old) | Yes |
| Redis |  Indirectly |
DNS & network instability | Yes |
| MySQL | Indirectly |
Network/DNS issues, improper container attachment | Yes |
| Docker 29.1.1 |  Not fully |
DNS partially fixed but API issues remain | — |
Conclusion for the Community
Docker 29.0.0–29.1.1 are not production-ready for environments that use Traefik, Redis, MySQL, or any services that rely on stable networking and Docker API functionality.
Use Docker 28.2.2 until third-party tools update their compatibility.
