---
title: "Airflow DAGs with no failure alert | Metacenta"
description: "A failed job nobody hears about shows yesterday's numbers as today's. How we check whether an Airflow, Dagster or Prefect failure reaches a person."
url: "https://metacenta.com/rules/dag-no-failure-alert"
updated: "2026-10-14"
tokens: 586
---

Orchestration & reliability · rule dag-no-failure-alert

# Airflow DAGs with no failure alert

A Metacenta review checks this under the rule **A failure reaches a person**. Everything below applies whether or not you ever commission one.

## What this rule checks

This rule flags each job file where nothing would tell a person about a failure. A failure callback, `email_on_failure=True`, a Dagster run-failure sensor or a Slack, PagerDuty or Opsgenie operator all pass. A callback set to `None` does not.

## Why it matters

This failure costs the most and announces itself the least. The job stops, the tables stop moving, and every dashboard downstream shows yesterday's numbers as today's. Somebody finds out days later, when a figure looks wrong in a meeting.

## How to fix it

**Make every job failure reach a person.** Wire `on_failure_callback` to wherever the team is already paged. Set it in `default_args`, so every task in the DAG inherits it.

Before:

```python
default_args = {
    "owner": "finance-data",
    "retries": 3,
}
```

After:

```python
default_args = {
    "owner": "finance-data",
    "retries": 3,
    "on_failure_callback": notify_on_call_rota,
}
```

## When it is fine to leave

Alerting wired globally, through a cluster policy, `airflow_local_settings.py` or a monitor on scheduler metrics, covers every DAG without appearing in any of them. When no job we review alerts, each finding names that as the likely explanation.

## What we need to check it

The job files you name to us one at a time. When `email_on_failure` is set by an expression we do not evaluate, we report that we could not tell, never that nobody is told.

[Ask about a review](https://metacenta.com/enquire?src=rule-dag-no-failure-alert&via=md)

## Related pages

- [Airflow DAG owner: how to set it and what it does](https://metacenta.com/rules/dag-unowned)
- [Airflow DAGs with no retries](https://metacenta.com/rules/dag-no-retries)
- [Airflow catchup: what it does and how to control it](https://metacenta.com/rules/dag-catchup-unbounded)
- [Passwords and API keys hardcoded in DAG files](https://metacenta.com/rules/dag-credential-literal)
- [A sample review, as a client reads it](https://metacenta.com/sample)
- [All published rules](https://metacenta.com/rules)
- [How a review is assessed](https://metacenta.com/standard)