guide/content/en/plugins/sanic-ext/health-monitor.md
The health monitor requires both sanic>=22.9 and sanic-ext>=22.9.
You can setup Sanic Extensions to monitor the health of your worker processes. This requires that you not be in single process mode.
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Out of the box, the health monitor is disabled. You will need to opt-in and enable the endpoint if you would like to use it.
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```python
app.config.HEALTH = True
app.config.HEALTH_ENDPOINT = True
```
The monitor sets up a new background process that will periodically receive acknowledgements of liveliness from each worker process. If a worker process misses a report too many times, then the monitor will restart that one worker.
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The health monitor will also enable a diagnostics endpoint that outputs the [worker state](../../guide/running/manager.md#worker-state). By default is id disabled.
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The diagnostics endpoint is not secured. If you are deploying it in a production environment, you should take steps to protect it with a proxy server if you are using one. If not, you may want to consider disabling this feature in production since it will leak details about your server state.
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```
$ curl http://localhost:8000/__health__
{
'Sanic-Main': {'pid': 99997},
'Sanic-Server-0-0': {
'server': True,
'state': 'ACKED',
'pid': 9999,
'start_at': datetime.datetime(2022, 10, 1, 0, 0, 0, 0, tzinfo=datetime.timezone.utc),
'starts': 2,
'restart_at': datetime.datetime(2022, 10, 1, 0, 0, 12, 861332, tzinfo=datetime.timezone.utc)
},
'Sanic-Reloader-0': {
'server': False,
'state': 'STARTED',
'pid': 99998,
'start_at': datetime.datetime(2022, 10, 1, 0, 0, 0, 0, tzinfo=datetime.timezone.utc),
'starts': 1
}
}
```
| Key | Type | Default | Description |
|---|---|---|---|
| HEALTH | bool | False | Whether to enable this extension. |
| HEALTH_ENDPOINT | bool | False | Whether to enable the diagnostics endpoint. |
| HEALTH_MAX_MISSES | int | 3 | The number of consecutive misses before a worker process is restarted. |
| HEALTH_MISSED_THRESHHOLD | int | 10 | The number of seconds the monitor checks for worker process health. |
| HEALTH_MONITOR | bool | True | Whether to enable the health monitor. |
| HEALTH_REPORT_INTERVAL | int | 5 | The number of seconds between reporting each acknowledgement of liveliness. |
| HEALTH_URI_TO_INFO | str | "" | The URI path of the diagnostics endpoint. |
| HEALTH_URL_PREFIX | str | "/__health__" | The URI prefix of the diagnostics blueprint. |