The Fix
pip install celery==5.6.1
Based on closed celery/celery issue #6301 · PR/commit linked
Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.
@@ -8,6 +8,16 @@ This document contains change notes for bugfix & new features
an overview of what's new in Celery 5.6.
+.. _version-5.6.1:
+
+5.6.1
Option A — Upgrade to fixed release\npip install celery==5.6.1\nWhen NOT to use: This fix is not applicable if using Redis without ACL authentication.\n\n
Why This Fix Works in Production
- Trigger: * [x] I have included all related issues and possible duplicate issues in this issue
- Mechanism: The Redis Sentinel backend fails to authenticate due to missing username extraction from the sentinel URL
- Why the fix works: Adds support for Redis Sentinel ACL authentication (username + password) in SentinelBackend, addressing issues with authentication failures. (first fixed release: 5.6.1).
- If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.
Why This Breaks in Prod
- The Redis Sentinel backend fails to authenticate due to missing username extraction from the sentinel URL
- Production symptom (often without a traceback): * [x] I have included all related issues and possible duplicate issues in this issue
Proof / Evidence
- GitHub issue: #6301
- Fix PR: https://github.com/celery/celery/pull/10013
- First fixed release: 5.6.1
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.75
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.78
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“> Additionally, I am not sure how to provide both redis master and sentinel passwords if they differ (using the same at the moment) The…”
“The documentation also seems to be wrong on the sentinel list in broker_url; if i don’t pass the database number, it will try to interpret…”
“I've submitted a PR to address part of this issue: https://github.com/celery/celery/pull/10013 This fix adds proper ACL authentication support (username + password) to SentinelBackend by: -…”
“> > Additionally, I am not sure how to provide both redis master and sentinel passwords if they differ (using the same at the moment)…”
Failure Signature (Search String)
- * [x] I have included all related issues and possible duplicate issues in this issue
- or possible duplicates to this issue as requested by the checklist above.
Copy-friendly signature
Failure Signature
-----------------
* [x] I have included all related issues and possible duplicate issues in this issue
or possible duplicates to this issue as requested by the checklist above.
Error Message
Signature-only (no traceback captured)
Error Message
-------------
* [x] I have included all related issues and possible duplicate issues in this issue
or possible duplicates to this issue as requested by the checklist above.
What Broke
Authentication failures occur when connecting to Redis Sentinels with enabled authentication.
Why It Broke
The Redis Sentinel backend fails to authenticate due to missing username extraction from the sentinel URL
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.6.1
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/celery/celery/pull/10013
First fixed release: 5.6.1
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix is not applicable if using Redis without ACL authentication.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
- Pin production dependencies and upgrade only with a reproducible test that hits the failing path.
Version Compatibility Table
| Version | Status |
|---|---|
| 5.6.1 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.