---
title: "Use the Alert Manager"
sidebar_label: "Alert Manager"
description: "Deploy the Alert Manager Marketplace app on a Barbara edge node and configure email + MQTT alerts for disk usage, service health, and external variables exposed over its REST API."
lastmod: "2026-09-29"
---

import VersionNotice from '@site/src/components/VersionNotice';
import { UpdateInProgressNotice } from '@site/src/components/VersionNotice';

<VersionNotice platformArticleVersion="v3.1.0" />
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## Overview

The **Alert Manager** is a Marketplace application that watches a Barbara edge node and triggers alerts when something goes wrong. It covers three channels of monitoring:

* **Service monitoring** — periodic health checks of selected workloads on the node, with retries before triggering an alert.
* **Telemetry monitoring** — every 60 seconds it compares the node's resource usage (notably disk) against user-defined warning and critical thresholds.
* **External variables** — a REST endpoint that lets your own apps push values to be evaluated against alarm rules.

Alerts are dispatched as **email** to a configurable recipient list, optionally over **MQTT** to a broker on the same node, with an optional **daily summary** email.

:::note[Looking for the platform alerts?]
The Alert Manager is independent of the notification rules in Barbara Panel. Notification rules watch your nodes from the platform and are configured per user; see [Alerts and notifications](/platform/alerts/overview/).
:::

## Add the Alert Manager to your Library

<a href="https://market.barbara.tech/application-detail/672351e3b9748be9ac94638c" target="_blank" class="app-info-link">
  <div class="app-info-box">
    <div class="app-corner-image">
      <img src={require('/img/MarketplaceLogo.png').default} alt="Marketplace badge" />
    </div>
    <div class="app-icon">
      <img src={require('/img/alarmmanager.png').default} alt="Alert Manager icon" />
    </div>
    <div class="app-details">
      <h3>Alert Manager</h3>
      <p>Watches services, telemetry, and external variables on an edge node and fires email or MQTT alerts when configured thresholds are breached.</p>
    </div>
  </div>
</a>

<div style={{ maxWidth: '900px', margin: '2em auto 2em auto', textAlign: 'center' }}>
  <img src={require('./img/alert_manager_marketplace.png').default} alt="Alert Manager in the Marketplace" className="shadow-img" />
  <figcaption style={{ fontSize: '0.9em', color: '#666', marginTop: '0.6em'}}>
    Alert Manager in the Marketplace
  </figcaption>
</div>

For the full Marketplace flow, see [Add a Marketplace app to your Library](/platform/apps-and-models/add-a-marketplace-app-to-your-library/).

## Deploy and configure disk monitoring

On the **Node Details** page of the target node, click **Add card → Application** and pick **Alert Manager** to launch the install wizard.

### App Secrets

The App Secrets carry the MQTT Broker credentials used when MQTT notifications are enabled. If you only want email alerts, leave the defaults — they are harmless when MQTT is off.

<div style={{ maxWidth: '900px', margin: '2em auto 2em auto', textAlign: 'center' }}>
  <img src={require('./img/app_secrets.png').default} alt="App Secrets in the install wizard" className="shadow-img" />
  <figcaption style={{ fontSize: '0.9em', color: '#666', marginTop: '0.6em'}}>
    App Secrets in the install wizard
  </figcaption>
</div>

### App Config — disk usage thresholds

Paste the following JSON in the App Config step to enable email alerts when disk usage crosses 75 % (warning) and 90 % (critical).

```json
{
  "alarmmanager": {
    "debugLevel": "info",
    "notification": {
      "email_enabled": true,
      "email_recipients": ["user@company.tech"],
      "mqtt_enabled": false,
      "summary_enabled": false,
      "summary_time_utc": "09:00"
    },
    "telemetry": {
      "disk_alarm_warning_threshold": 75,
      "disk_alarm_critical_threshold": 90
    },
    "services": []
  }
}
```

<div style={{ maxWidth: '900px', margin: '2em auto 2em auto', textAlign: 'center' }}>
  <img src={require('./img/app_config.png').default} alt="App Config in the install wizard" className="shadow-img" />
  <figcaption style={{ fontSize: '0.9em', color: '#666', marginTop: '0.6em'}}>
    App Config in the install wizard
  </figcaption>
</div>

Key fields:

| Field | Description |
| --- | --- |
| `notification.email_enabled` | Toggle email alerts on/off. |
| `notification.email_recipients` | List of email addresses to send alerts to. |
| `notification.mqtt_enabled` | Toggle MQTT alerts on/off (requires an MQTT broker on the node). |
| `telemetry.disk_alarm_warning_threshold` | Disk usage % that triggers a warning alert. |
| `telemetry.disk_alarm_critical_threshold` | Disk usage % that triggers a critical alert. |

Click **Send App**. Alerts now fire whenever disk usage crosses the thresholds.

## Monitor a deployed service

Add an entry to the `services` array of the App Config to watch a workload on the node. The example below watches the Marketplace MQTT Broker (service name `mqttbbr`) and triggers an alert if its container goes down for more than 30 seconds and one retry:

```json
{
  "alarmmanager": {
    "debugLevel": "info",
    "notification": {
      "email_enabled": true,
      "email_recipients": ["user@company.tech"],
      "mqtt_enabled": true,
      "summary_enabled": true,
      "summary_time_utc": "16:50"
    },
    "telemetry": {
      "disk_alarm_warning_threshold": 40,
      "disk_alarm_critical_threshold": 90
    },
    "services": [
      {
        "enabled": true,
        "serviceName": "mqttbbr",
        "interval": 30,
        "retries": 1
      }
    ]
  }
}
```

| Field | Description |
| --- | --- |
| `enabled` | Toggle this service entry on/off. |
| `serviceName` | The container's service name as declared in its compose file. |
| `interval` | Seconds between health checks. |
| `retries` | Failed checks before the alert fires. |

:::tip[Find the service name]

Open the **Docker Compose Info** segment of any workload card on the Node Details page. The `serviceName` is the key under `services:` of the compose file.

:::

<div style={{ maxWidth: '500px', margin: '2em auto 2em auto', textAlign: 'center' }}>
  <img src={require('./img/mqttbbr_service.png').default} alt="Finding the mqttbbr service name in Docker Compose Info" className="shadow-img" />
  <figcaption style={{ fontSize: '0.9em', color: '#666', marginTop: '0.6em'}}>
    Finding the `mqttbbr` service name in Docker Compose Info
  </figcaption>
</div>

## Monitor external variables over REST

The Alert Manager exposes a REST endpoint at **`http://alarmmanager:5100/event`** on the node's [`barbaraServices` network](/developers/app-development-tutorial/step-09-network-management/). Any workload on the same node — your own or a Marketplace app — can POST evaluation requests to it.

The payload is a list of event objects:

```json
{
  "enabled": false,
  "name": "Low pressure",
  "deviceDisplayName": "machine_01",
  "displayName": "variable_01",
  "value": 20,
  "operation": "<",
  "threshold": 19,
  "retries": 3
}
```

Example Python client:

```python
import json
import requests

url = "http://alarmmanager:5100/event"

payload = json.dumps([
    {
        "enabled": True,
        "name": "Low pressure",
        "deviceDisplayName": "machine_00",
        "displayName": "variable_01",
        "value": 18,
        "operation": "<",
        "threshold": 19,
        "retries": 3,
    },
    {
        "enabled": False,
        "name": "Low pressure",
        "deviceDisplayName": "machine_01",
        "displayName": "variable_01",
        "value": 20,
        "operation": "<",
        "threshold": 19,
        "retries": 3,
    },
])

response = requests.post(url, headers={"Content-Type": "application/json"}, data=payload)
print(response.text)
```

See the app's Technical Notes on Marketplace for the full payload reference.

## Use with Marketplace industrial connectors

Every industrial connector in the Barbara Marketplace ships pre-integrated with the Alert Manager — you only need to add the alarm configuration to the connector's App Config to start receiving alerts on its variables.

:::note[See also...]

Browse the connector catalogue and read the per-connector Technical Notes at <a href="https://market.barbara.tech/category-detail/64afa020d8c2a5f80573b45f" target="_blank" rel="noopener noreferrer">Industrial Connectors in Barbara Marketplace</a>.

:::

## Daily summary email

The Alert Manager can send a once-a-day digest email with every event that occurred in the previous 24 hours. Enable it under `notification`:

| Field | Description |
| --- | --- |
| `notification.summary_enabled` | Enable the daily summary email. |
| `notification.summary_time_utc` | Time of day (UTC, `HH:MM`) when the summary is sent. |

Example:

```json
{
  "alarmmanager": {
    "debugLevel": "info",
    "notification": {
      "email_enabled": true,
      "email_recipients": ["user@company.tech"],
      "mqtt_enabled": false,
      "summary_enabled": true,
      "summary_time_utc": "09:00"
    },
    "telemetry": {
      "disk_alarm_warning_threshold": 75,
      "disk_alarm_critical_threshold": 90
    },
    "services": []
  }
}
```

## Summary

The Alert Manager is the catch-all alerting layer for a Barbara node: telemetry thresholds out of the box, service health checks with retries, and a REST endpoint that lets any app on the `barbaraServices` network push variables for evaluation. Email and MQTT cover the notification side, with an optional daily summary digest.