Celery Celery exit with non-zero code after Warm Shutdown

The Fix

pip install celery==5.3.6

Based on closed celery/celery issue #8540 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Jump to Verify Open PR/Commit

@@ -580,7 +580,7 @@ def autoscale(state, max=None, min=None):
     """Shutdown worker(s)."""
     logger.warning(msg)
-    raise WorkerShutdown(msg)
+    raise WorkerShutdown(0)

repro.py

from celery import Celery

app = Celery('tasks')

@app.task
def add(x, y):
    return x + y

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\npip install celery==5.3.6\nWhen NOT to use: This fix should not be applied if the worker's exit behavior is intentionally designed to return non-zero codes.\n\n

Why This Fix Works in Production

Trigger: We upgraded recently **celery** from **5.2.7** to **5.3.4** and something changed in the default behaviour of a celery worker when it receives a warm shutdown.
Mechanism: The worker raised a non-integer exit code during a warm shutdown after the upgrade
Why the fix works: Fixes the non-zero exit code issue when receiving a remote shutdown in Celery 5.3.x. (first fixed release: 5.3.6).

Production impact:

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

Shows up under Python 3.9 in real deployments (not just unit tests).
The worker raised a non-integer exit code during a warm shutdown after the upgrade
Production symptom (often without a traceback): We upgraded recently **celery** from **5.2.7** to **5.3.4** and something changed in the default behaviour of a celery worker when it receives a warm shutdown.

Proof / Evidence

GitHub issue: #8540
Fix PR: https://github.com/celery/celery/pull/8650
First fixed release: 5.3.6
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.72

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“The upcoming smoke tests will include a test for this issue: https://github.com/celery/celery/blob/ecd8994f771b679678dd087725e1fac9e72db1b3/t/smoke/tests/test_control.py#L9”

@Nusnus · 2023-12-06 · source

“If you can propose a fix, it would be great. we can discuss more on the PR.”

@auvipy · 2023-10-02 · source

“what is the content of requirements.txt? @cinesia”

@badziyoussef · 2023-10-13 · source

“> what is the content of requirements.txt? @cinesia Just the version of celery I want to install.”

@cinesia · 2023-10-14 · source

Failure Signature (Search String)

We upgraded recently **celery** from **5.2.7** to **5.3.4** and something changed in the default behaviour of a celery worker when it receives a warm shutdown.
The code it's the same and nothing changed except the package upgrade.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
We upgraded recently **celery** from **5.2.7** to **5.3.4** and something changed in the default behaviour of a celery worker when it receives a warm shutdown.
The code it's the same and nothing changed except the package upgrade.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
We upgraded recently **celery** from **5.2.7** to **5.3.4** and something changed in the default behaviour of a celery worker when it receives a warm shutdown.
The code it's the same and nothing changed except the package upgrade.

Minimal Reproduction

repro.py

from celery import Celery

app = Celery('tasks')

@app.task
def add(x, y):
    return x + y

Environment

Python: 3.9

What Broke

Workers exit with a non-zero code after receiving a shutdown command, causing deployment issues.

Why It Broke

The worker raised a non-integer exit code during a warm shutdown after the upgrade

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install celery==5.3.6

When NOT to use: This fix should not be applied if the worker's exit behavior is intentionally designed to return non-zero codes.

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/8650

First fixed release: 5.3.6

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

This fix should not be applied if the worker's exit behavior is intentionally designed to return non-zero codes.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

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
5.3.6	Fixed

Related Issues

No related fixes found.

Cluster: celery:configuration-error Celery hub Celery best practices All hubs All clusters

Related clusters: Data consistency Duplicates Duplicate processing

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.

Celery Celery exit with non-zero code after Warm Shutdown in Celery 5.3.x (Fix)